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  Subjects -> ENGINEERING (Total: 1955 journals)
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ENGINEERING (1111 journals)            First | 4 5 6 7 8 9 10 11 | Last

Journal of Nanotechnology in Engineering and Medicine     Full-text available via subscription   (Followers: 5)
Journal of Natural Gas Science and Engineering     Hybrid Journal   (Followers: 3)
Journal of Near Infrared Spectroscopy     Full-text available via subscription   (Followers: 7)
Journal of Networks     Open Access   (Followers: 4)
Journal of Nonlinear Dynamics     Open Access  
Journal of Oceanography and Marine Science     Open Access   (Followers: 2)
Journal of Operations Management     Hybrid Journal   (Followers: 13)
Journal of Optics     Hybrid Journal   (Followers: 2)
Journal of Organizational Behavior     Hybrid Journal   (Followers: 20)
Journal of Petroleum Science Research     Open Access   (Followers: 1)
Journal of Phase Equilibria and Diffusion     Hybrid Journal  
Journal of Power Sources     Partially Free   (Followers: 22)
Journal of Pre-College Engineering Education Research     Open Access  
Journal of Pressure Vessel Technology     Full-text available via subscription   (Followers: 10)
Journal of Professional Issues in Engineering Education and Practice     Full-text available via subscription   (Followers: 6)
Journal of Quality and Reliability Engineering     Open Access  
Journal of Quality in Maintenance Engineering     Hybrid Journal   (Followers: 3)
Journal of Radiation Research and Applied Sciences     Open Access   (Followers: 1)
Journal of Rare Earths     Full-text available via subscription   (Followers: 2)
Journal of Real-Time Image Processing     Hybrid Journal   (Followers: 7)
Journal of Regional Science     Hybrid Journal   (Followers: 6)
Journal of Reinforced Plastics and Composites     Hybrid Journal   (Followers: 4)
Journal of Research of NIST     Open Access   (Followers: 1)
Journal of Rock Mechanics and Geotechnical Engineering     Open Access   (Followers: 2)
Journal of Russian Laser Research     Hybrid Journal  
Journal of Safety Engineering     Open Access   (Followers: 3)
Journal of Safety Research     Hybrid Journal   (Followers: 4)
Journal of Science and Technology     Open Access  
Journal of Science and Technology (Ghana)     Open Access   (Followers: 1)
Journal of Science and Technology Policy Management     Hybrid Journal   (Followers: 3)
Journal of Scientific Computing     Hybrid Journal   (Followers: 2)
Journal of Scientific Innovations for Development     Open Access   (Followers: 2)
Journal of Semiconductors     Full-text available via subscription   (Followers: 2)
Journal of Sensor Technology     Open Access   (Followers: 2)
Journal of Shanghai Jiaotong University (Science)     Hybrid Journal  
Journal of Sol-Gel Science and Technology     Hybrid Journal   (Followers: 2)
Journal of Solar Energy     Open Access   (Followers: 2)
Journal of Solar Energy Engineering     Full-text available via subscription   (Followers: 14)
Journal of Superconductivity and Novel Magnetism     Partially Free   (Followers: 1)
Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques     Hybrid Journal   (Followers: 1)
Journal of Surveying Engineering     Full-text available via subscription   (Followers: 7)
Journal of Technology Management & Innovation     Open Access   (Followers: 3)
Journal of Telecommunications Management     Full-text available via subscription   (Followers: 2)
Journal of Testing and Evaluation     Full-text available via subscription   (Followers: 9)
Journal of the Air & Waste Management Association     Hybrid Journal   (Followers: 3)
Journal of the Chinese Institute of Engineers     Hybrid Journal  
Journal of the Chinese Institute of Industrial Engineers     Hybrid Journal   (Followers: 1)
Journal of the Franklin Institute     Full-text available via subscription   (Followers: 2)
Journal of the Institution of Engineers (India ): Series D     Hybrid Journal  
Journal of the Institution of Engineers (India) : Series B     Hybrid Journal   (Followers: 1)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal  
Journal of the Institution of Engineers (India): Series A     Hybrid Journal  
Journal of the Institution of Engineers (India): Series C     Hybrid Journal   (Followers: 1)
Journal of the National Science Foundation of Sri Lanka     Open Access   (Followers: 1)
Journal of the University of Ruhuna     Open Access  
Journal of Thermal Science and Engineering Applications     Full-text available via subscription   (Followers: 2)
Journal of Thermal Stresses     Hybrid Journal   (Followers: 3)
Journal of Transplantation     Open Access   (Followers: 3)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 5)
Journal of Transportation Engineering     Full-text available via subscription   (Followers: 12)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 13)
Journal of Tribology     Full-text available via subscription   (Followers: 8)
Journal of Turbomachinery     Full-text available via subscription   (Followers: 6)
Journal of Turbulence     Hybrid Journal  
Journal of Unmanned Vehicle Systems     Full-text available via subscription   (Followers: 1)
Journal of Urban and Environmental Engineering     Open Access  
Journal of Urban Planning and Development     Full-text available via subscription   (Followers: 27)
Journal of Urban Regeneration and Renewal     Full-text available via subscription   (Followers: 10)
Journal of Vibration and Acoustics     Full-text available via subscription   (Followers: 21)
Journal of Visualization     Hybrid Journal   (Followers: 2)
Journal of Volcanology and Seismology     Hybrid Journal   (Followers: 1)
Journal of Wuhan University of Technology-Mater. Sci. Ed.     Hybrid Journal  
Journal of X-Ray Science and Technology     Hybrid Journal  
Journal of Zhejiang University SCIENCE A     Hybrid Journal  
Journal on Chain and Network Science     Full-text available via subscription   (Followers: 2)
Jurnal Teknologi     Open Access   (Followers: 1)
Karaelmas Science and Engineering Journal     Open Access  
Kleio     Full-text available via subscription   (Followers: 2)
Landscape and Ecological Engineering     Hybrid Journal   (Followers: 3)
Langmuir     Full-text available via subscription   (Followers: 35)
Leadership and Management in Engineering     Full-text available via subscription   (Followers: 10)
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Lighting Research and Technology     Hybrid Journal  
Logic and Analysis     Hybrid Journal  
Logica Universalis     Hybrid Journal  
Lubrication Science     Hybrid Journal  
Machines     Open Access  
Machining Science and Technology: An International Journal     Hybrid Journal   (Followers: 2)
Macromolecular Reaction Engineering     Hybrid Journal  
Magazine of Concrete Research     Hybrid Journal   (Followers: 4)
Magdeburger Journal zur Sicherheitsforschung     Open Access  
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 1)
Management and Production Engineering Review     Open Access  
Management Science and Engineering     Open Access   (Followers: 1)
Manufacturing Engineer     Hybrid Journal   (Followers: 4)
Manufacturing Research and Technology     Full-text available via subscription   (Followers: 5)
MATEC Web of Conferences     Open Access  
Matériaux & Techniques     Full-text available via subscription   (Followers: 1)
Mathematical Models and Methods in Applied Sciences     Hybrid Journal   (Followers: 2)
Mathematical Problems in Engineering     Open Access   (Followers: 3)

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Journal Cover Pest Management Science
   Journal TOC RSS feeds Export to Zotero [7 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1526-498X - ISSN (Online) 1526-4998
     Published by John Wiley and Sons Homepage  [1603 journals]   [SJR: 0.99]   [H-I: 64]
  • The push‐pull strategy for citrus psyllid control
    • Authors: Huaxue Yan; Jiwu Zeng, Guangyan Zhong
      Pages: n/a - n/a
      Abstract: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the only natural vector of “Candidatus Liberibacter asiaticus” that causes citrus Huanglongbing (HLB), a most destructive disease of citrus. Currently no remedial therapy exists for the disease and so effective control of ACP is very important in curbing the transmission of the disease. The push‐pull strategy should be thoroughly explored as an approach to ACP management. This mini‐review summarizes the current progress towards more effective repellent and attractant chemicals through investigating known repellent and attractive plants. Interactions between ACP and its host plants are also addressed, with emphasis on the possible involvement of the host biochemicals in attracting the insect. Potential ways to increase the effectiveness of the pull‐push strategy are briefly discussed. It is expected that the pull‐push strategy will be gradually developed following more extensive research.
      PubDate: 2014-09-25T02:00:47.963676-05:
      DOI: 10.1002/ps.3915
       
  • Natural enemy‐mediated indirect interactions among prey species:
           potential for enhancing biocontrol services in agro‐ecosystems
    • Authors: Anaïs Chailleux; Emily K. Mohl, Mickaël Teixeira Alves, Gerben J. Messelink, Nicolas Desneux
      Pages: n/a - n/a
      Abstract: Understanding how arthropod pests and their natural enemies interact in complex agro‐ecosystems is essential for pest management programs. Theory predicts that prey sharing a predator, such as a biological control agent, can indirectly reduce each other's density at equilibrium (apparent competition). From this premise, we (i) discuss the complexity of indirect interactions among pests in agro‐ecosystems and highlight the importance of natural enemy‐mediated indirect interactions other than apparent competition, (ii) outline factors that affect the nature of enemy‐mediated indirect interactions in the field, and (iii) identify the way to manipulate enemy‐mediated interactions for biological control. We argue that there is a need to increase the link between community ecology theory and biological control to develop better agro‐ecological methods of crop protection via conservation biological control. In conclusion we identify (i) interventions to be chosen depending on agroecosystems characteristics and (ii) several lines of research that will improve the potential for enemy‐mediated indirect interactions to be applied to biological control.
      PubDate: 2014-09-25T02:00:44.771447-05:
      DOI: 10.1002/ps.3916
       
  • Local and global inverse modeling strategies to estimate parameters for
           pesticide leaching from lysimeter studies
    • Authors: Gunnar M Kahl; Yury Sidorenko, Bernhard Gottesbüren
      Pages: n/a - n/a
      Abstract: Background As an option for higher tier leaching assessment of pesticides in Europe according to FOCUS, pesticide properties can be estimated from lysimeter studies by inversely fitting parameter values (DT50 and kom). The aim of the study was to identify adequate methods for inverse modelling. Results Model parameters for the PEARL model were estimated with different inverse optimization algorithms (Levenberg‐Marquardt, PD_MS2, SCEM). Optimization of crop factors and hydraulic properties was found to be an ill posed problem and all algorithms failed to identify reliable global minima for the hydrological parameters. All algorithms performed equally well in estimating pesticide sorption and degradation parameters. SCEM was in most cases the only algorithm that reliably calculated uncertainties. Conclusion The most reliable approach for finding the best parameter set in the stepwise approach of optimizing evapotranspiration, soil hydrology and pesticide parameters was to run only SCEM or a combined approach with more than one algorithm using the best fit of each step for further processing. PD_MS2 was well suitable for a quick parameter search. The linear parameter uncertainty intervals estimated by LM and PD_MS2 were usually larger than by the non‐linear method used by SCEM. With the suggested methods parameter optimization together with reliable estimation of uncertainties is possible also for relatively complex systems.
      PubDate: 2014-09-24T03:38:15.147528-05:
      DOI: 10.1002/ps.3914
       
  • Termite (Order Blattodea, Infraorder Isoptera) baiting 20 years after
           commercial release
    • Authors: Theodore A. Evans; Naeem Iqbala
      Pages: n/a - n/a
      Abstract: Termite baiting is now one of the two main management tools in developed countries after 20 years of commercial release. It has two main goals: to use small amounts of active ingredient and ‘colony elimination’, viz. death of all individuals in the colony. We consider how well baiting has been evaluated from 100 studies in the scientific literature. Studies have included 15 active ingredients, 23 termite species and 16 countries, yet most studies were of the chitin synthesis inhibitor hexaflumuron, Reticulitermes, and the USA. Baiting has mostly met its goals: typically about 0.5 gram of active ingredient was used; and colony elimination achieved, albeit rates varied from 0‐100%, and were sometimes supplemented with liquid insecticide. Baiting was most successful using chitin synthesis inhibitors against Reticulitermes and Coptotermes (Rhinotermitidae), in temperate locations, although colony elimination was usually inferred indirectly ‐ mostly by termite absence from baits ‐ and was often slow, from 25 to 450 days. Baiting has been less tested and less successful against higher termites in tropical locations, where they are most diverse and abundant. Future research may have to consider greater termite species diversity and other active ingredients to reduce control times to fulfil the potential of baiting.
      PubDate: 2014-09-22T02:05:24.277073-05:
      DOI: 10.1002/ps.3913
       
  • Characterization and inhibition studies of Helicoverpa armigera (Hubner)
           gut α‐amylase
    • Authors: Rimaljeet Kaur; Anil K Gupta, Gaurav K Taggar
      Pages: n/a - n/a
      Abstract: Background The survival of a devastating pest, Helicoverpa armigera, is mainly dependent on the availability of α‐amylase. Therefore, the characterization of H. armigera α‐amylase and targeting it with effective inhibitors could aid in reducing its damaging effects. Results H. armigera gut possessed four isozymes of α‐amylase. The molecular weight of major purified isozyme ranged from 79–81 kDa. The purified enzyme was identified to be α‐amylase on the basis of products formed from starch. The optimum pH and temperature were 10.0 and 50 °C, respectively. Activation energy was 5.7 kcal/mol. The enzyme showed high activity with starch and amylopectin whereas dextrins were the poor substrates. Km with starch, amylose and amylopectin was 0.45, 1.23 and 0.11 mg ml−1, respectively. ZnSO4, FeSO4, CuSO4, citric acid, oxalic acid and salicylic acid were the potent inhibitors. ZnSO4, salicylic acid and pigeonpea α‐amylase inhibitor (~21.0 kDa) acted primarily as competitive inhibitors, FeSO4 and citric acid displayed mainly anticompetitive behaviour while CuSO4 and oxalic acid behaved mainly as non‐competitive inhibitors. Conclusions The identification of effective ecofriendly inhibitors could help in managing H. armigera infestation.
      PubDate: 2014-09-19T03:40:47.321668-05:
      DOI: 10.1002/ps.3911
       
  • Novel control methods for insect pests: Development of a
           microencapsulation procedure for proteinaceous bio‐actives intended
           for oral delivery.
    • Authors: Elaine H Richards; Tim Wontner‐Smith, Hannah Bradish, M Paulina Dani, Jane V Cotterill
      Pages: n/a - n/a
      Abstract: Background The objective was to develop an environmentally favourable microcapsule suitable for delivery of proteinaceous bio‐active agents ('bio‐insecticides') to pest insects. Results Utilising feeding bio‐assays, we determined that microspheres made of alginate can be produced in a variety of sizes and are palatable and non‐toxic to larvae of the lepidopteran pest, Lacanobia oleracea. Dehydrated microspheres were also readily ingested by larvae. Using a novel feeding bio‐assay and alginate microspheres containing a fluorescent marker material (coumarin 7 encapsulated in styrene maleic anhydride beads), we determined that the microspheres successfully deliver the marker to the insect gut. Moreover, the alginate microspheres rapidly break down in the alkaline conditions of the insect gut and release their contents, the beads passing through the gut in 2 to 3 h. Using BSA as a test protein and western blotting, it was determined that alginate can successfully encapsulate protein, and that the microspheres can be stored in a CaCl2 solution for up to 24 days without extensive leakage. Importantly, it was also determined that alginate and the microsphere‐making procedure developed, do not inactivate rVPr1 (an insect immunosuppressive protein and potential bio‐insecticide). Conclusions An alginate‐based microsphere has potential to deliver the proteinaceous bio‐active, rVPr1, to pest insects.
      PubDate: 2014-09-18T10:43:05.328947-05:
      DOI: 10.1002/ps.3912
       
  • Molecular assessment of predation by hoverflies (Diptera: Syrphidae) in
           Mediterranean lettuce crops.
    • Authors: Priscila Gomez‐Polo; Oscar Alomar, Cristina Castañé, Jonathan G. Lundgren, Josep Piñol, Nuria Agustí
      Pages: n/a - n/a
      Abstract: Background Hoverflies (Diptera: Syrphidae) are generalist predators of a great variety of pests. Nasonovia ribisnigri (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae) are two common pests in Mediterranean lettuce crops, where they occur alongside alternative prey (e.g., Collembola). A semi‐field experiment was conducted in an experimental lettuce plot where hoverfly predation on N. ribisnigri, F. occidentalis and Collembola was studied by conventional and qPCR using specific primers, as well as by Next Generation Sequencing (NGS) in order to reveal other potential trophic interactions. Results Trophic linkages between hoverflies and N. ribisnigri were the strongest both in spring and summer. Frankliniella occidentalis and Collembolans were also detected in both seasons but with less frequency. qPCR detected a higher frequency of consumption than conventional PCR when both tests were run at optimal conditions. NGS analyses showed intraguild predation (IGP) on other hoverflies species, as well as on anthocorids, spiders and even aphid parasitoids. Conclusions Conventional and qPCR provided important insights into Mediterranean hoverfly species predation on target pest and non‐pest prey. NGS gave a complementary approach revealing a broader diet of these predators within the studied ecosystem.
      PubDate: 2014-09-18T10:42:40.741529-05:
      DOI: 10.1002/ps.3910
       
  • Construction of immobilized‐AChE column and its application in
           screening insecticidal constituents from Magnolia officinalis
    • Authors: Yong‐Hao Ye; Cong Li, Jun Yang, Liang Ma, Yu Xiao, Jun Hu, Nasir Ahmed Rajput, Cong‐Fen Gao, Ying‐Ying Zhang, Ming‐Hua Wang
      Pages: n/a - n/a
      Abstract: Background Application of matrix‐immobilized target enzyme for screening inhibitors is widely used in drug development, however there are few studies in insecticide discovery. In this paper, an economical and effective immobilized‐AChE column was prepared using sol–gel embedding method, which was further combined with HPLC for screening the AChE inhibitors and insecticidal compounds from complex natural products. Results AChE inhibitory constituents, magnolol (1) and honokiol (2), were isolated from the ethanol extract of Magnolia officinalis with the IC50 values of 0.069 and 0.057 mM, respectively. In vivo bioassay indicated 1 and 2 showed insecticidal activity against Nilaparvata lugens with the LC50 values of 0.324 and 0.137 mM comparable to that of commonly used insecticide chlorpyrifos (0.233 mM). Moreover, molecular docking was carried out against the homology model of N. lugens AChE. The complexes showed that 1 and 2 placed themselves nicely into the active site of the enzyme and exhibit interaction energy which was in accordance with our activity profile data. Conclusion These results demonstrated that 1 and 2 had great applied potential to be developed as natural insecticides, and immobilized‐AChE column is very useful as rapid screening tool for the target enzymes towards potent inhibitors.
      PubDate: 2014-09-16T12:00:49.836996-05:
      DOI: 10.1002/ps.3908
       
  • Prospects for the use of biological control agents against Anoplophora in
           Europe
    • Authors: Thomas Brabbs; Debbie Collins, Franck Hérard, Matteo Maspero, Dominic Eyre
      Pages: n/a - n/a
      Abstract: This review summarises the literature on the biological control of Anoplophora spp. (Coleoptera: Cerambycidae) and discusses its potential for use in Europe. Entomopathogenic fungi: Beauveria brongniartii Petch (Hypocreales: Cordycipitaceae) has already been developed into a commercial product in Japan and fungal infection results in high mortality rates. Parasitic nematodes: Steinernema feltiae Filipjev (Rhabditida: Steinernematidae) and Steinernema carpocapsae Weiser have potential for use as biopesticides as an alternative to chemical treatments. Parasitoids: A parasitoid of Anoplophora chinensis Forster, Aprostocetus anoplophorae Delvare (Hymenoptera: Eulophidae), was discovered in Italy in 2002 and has been shown to be capable of parasitizing up to 72% of A. chinensis eggs. Some native European parasitoid species (e.g. Spathius erythrocephalus) also have potential to be used as biological control agents. Predators: Two woodpecker (Piciformis: Picidae) species that are native to Europe, Dendrocopos major Beicki and Picus canus Gmelin have been shown to be effective at controlling Anoplophora glabripennis Motschulsky in Chinese forests. The removal and destruction of infested and potentially infested trees is the main eradication strategy for Anoplophora sp. in Europe, but biological control agents could be used in the future to complement other management strategies, especially in locations where eradication is no longer possible.
      PubDate: 2014-09-12T05:40:45.68928-05:0
      DOI: 10.1002/ps.3907
       
  • Sensitivity to cymoxanil in Italian populations of Plasmopara viticola
           oospores
    • Authors: Silvia L. Toffolatti; Giovanni Venturini, Paola Campia, Lorenzo Cirio, Diego Bellotto, Annamaria Vercesi
      Pages: n/a - n/a
      Abstract: Background The level of sensibility towards cymoxanil was quantified by oospore germination assays in 28 populations of Plasmopara viticola (Berk. et Curt.) Berlese and De Toni sampled from different Italian regions from 2009 until 2012. Results The populations showed good sensitivity levels, with EC50 values often lower than 10 mg/L of active ingredient and percentages of resistant individuals lower than 16 %. Only three populations, sampled at the end of grapevine growing season 2012, were characterized by high resistance levels. Field trials carried out in two of these vineyards showed that at the beginning of grapevine growing season 2013, the EC50 values of P. viticola populations as measured in the sporangial assay were higher than those observed with oospores. At the end of the season, in plots where cymoxanil was not applied, the populations fully reverted to sensitivity, while the EC50 values remained high where 3 to 6 applications were performed. Conclusion Oospore germination assays provide valuable information on the sensitivity of populations in vineyards also at the quantitative level. The results obtained during grapevine growing season confirm those obtained on the oospores and that cymoxanil resistance is unstable, indirectly suggesting that the application of the fungicide according to anti‐resistance strategies can lead to a good disease control.
      PubDate: 2014-09-12T04:16:34.597711-05:
      DOI: 10.1002/ps.3906
       
  • First report of Bemisia tabaci Mediterranean (Q biotype) species in Brazil
    • Authors: Leonardo da Fonseca Barbosa; Valdir Atsushi Yuki, Julio Massaharu Marubayashi, Bruno Rossitto De Marchi, Fernando Luis Perini, Marcelo Agenor Pavan, Danielle Ribeiro de Barros, Murad Ghanim, Enrique Moriones, Jesus Navas‐Castillo, Renate Krause Sakate
      Pages: n/a - n/a
      Abstract: Background The Whitefly Bemisia tabaci is a major cosmopolitan pest and comprises a complex of more than 35 cryptic species that cause serious damage to agricultural crops worldwide. In this study, the Mediterranean species of B. tabaci, formerly known as Q biotype, was identified for the first time in Brazil. Results Adult B. tabaci were collected from different localities and hosts from Rio Grande do Sul, the southernmost state of the country that borders to Uruguay and Argentina. Partial sequencing of the mitochondrial cytochrome oxidase I (mtCOI) gene indicated that B. tabaci MED species appears to be restricted to the Provincia of Barra do Quaraí, infesting Capsicum annuum cultivated in greenhouses and Ipomoea batatas in open fields. The partial mtCOI sequences obtained shared 100% nucleotide identity with reference sequences for the Q biotype reported from Uruguay. The secondary endosymbionts Hamiltonella and Cardinium were detected by PCR in the new identified MED species from Brazil, similar to the Q biotype from Uruguay. Conclusion Our results indicate the presence of the MED species in Brazil. The close monitoring of this new identified species in the Southern region of Brazil is essential to avoid its geographical expansion to more important agricultural areas in the country.
      PubDate: 2014-09-12T04:13:17.590039-05:
      DOI: 10.1002/ps.3909
       
  • Enhanced repellency of binary mixtures of Calophyllum inophyllum nut oil
           fatty acids or their esters and three terpenoids to Stomoxys calcitrans
    • Authors: Tran Trung Hieu; Won Sil Choi, Soon‐Il Kim, Mo Wang, Young‐Joon Ahn
      Pages: n/a - n/a
      Abstract: Background An assessment was made of the repellency to female stable flies of tamanu nut oil fatty acids or their esters alone (each 0.5 mg cm−2) or in combination with cuminyl alcohol, cuminaldehyde and α‐phellandrene (each 0.25 mg cm−2) using an exposed human hand bioassay. Results were compared with those of synthetic repellent deet (0.25 mg cm−2). Results Based upon protection time (PT) (time to first bite of stable fly), oleic acid, linoleic acid, methyl oleate or methyl linoleate synergized the repellency of each monoterpenoid and deet. For example, the binary mixture of oleic acid and cuminyl alcohol (PT, 2.05 h) resulted in significantly greater repellency than either oleic acid (0.55 h), cuminyl alcohol (0.70 h) or deet alone (1.50 h). The binary mixtures of oleic acid and cuminyl alcohol or deet (PT, 2.10 h) did not differ significantly in repellency. Structure–activity relationship indicates that degrees of saturation, side chain length and functional group of fatty acids appear to play a role in determining the fatty acid repellency to stable flies. Conclusion Mixtures formulated from fatty acid and monoterpenoid described could be useful as potential repellents for protecting humans and possibly domestic animals from bites caused by stable fly.
      PubDate: 2014-09-10T03:59:10.938085-05:
      DOI: 10.1002/ps.3904
       
  • Eradication of Tephritid Fruit Fly Pest Populations: Outcomes and
           Prospects
    • Authors: D. M. Suckling; J. M. Kean, L. D. Stringer, C. Cáceres‐Barrios, J. Hendrichs, J. Reyes‐Flores, B. Dominiak
      Pages: n/a - n/a
      Abstract: Background The number of insect eradication programs is rising in response to globalisation. A database of arthropod and plant pathogen eradications covers 1050 incursion responses, with 928 eradication programs on 299 pest and disease taxa in 104 countries (b3.net.nz/gerda). Methods A subset of the database was assembled with 211 eradication or response programs against 17 species of fruit flies (Tephritidae) in 31 countries, in order to investigate factors affecting the outcome. Results The failure rate for fruit fly eradication programs was about 7%, with 0% for Ceratitis capitata (n = 85 programs), and 0% for two Anastrepha species (n = 12 programs), but 12% for 13 Bactrocera species (n = 108 programs). A number of intended eradication programs against long‐established populations were not initiated because of cost and other considerations, or evolved during the planning phase into suppression programs. Cost was dependent on area, ranged from USD 0.1‐240 million, and averaged ~12 million (normalised to USD in 2012). In addition to the routine use of surveillance networks, quarantine and fruit destruction, the key tactics used in eradication programs were male annihilation, protein bait sprays (which can attract both sexes), fruit destruction and the sterile insect technique. Conclusions Eradication success generally required the combination of several tactics applied on an area‐wide basis. Because the likelihood of eradication declines with an increase in the area infested, it pays to invest in effective surveillance networks that allow early detection and delimitation while invading populations are small, thereby greatly favouring eradication success.
      PubDate: 2014-09-10T03:30:41.570511-05:
      DOI: 10.1002/ps.3905
       
  • RNA interference of P450 CYP6CM1 gene has different efficacy in B and Q
           biotypes of Bemisia tabaci
    • Authors: Jingjing Li; Xiaomin Li, Rune Bai, Yan Shi, Qingbo Tang, Shiheng An, Qisheng Song, Fengming Yan
      Pages: n/a - n/a
      Abstract: Background Cytochrome P450 monooxygenses have been proven to be associated with high resistance in Bemisia tabaci B (Middle East‐Minor Asia 1 genetic group) and Q (Mediterranean genetic group) biotypes to neonicotinoid class of insecticides. In this study, the RNA interference (RNAi) effects on P450 CYP6CM1 gene expression, mortality, and pesticide‐detoxifying ability between B. tabaci B and Q biotypes were compared in an attempt to provide basis for potential RNAi application in management of this pest. Rsults Double‐stranded RNAs (dsRNA) of P450 CYP6CM1 genes corresponding to the B and Q biotypes were synthesized using specific primers and introduced into the insect body of B. tabaci adults through membrane feeding. The results showed that dsRNA significantly silenced the target genes in B. tabaci with dsRNA concentrations or treatment time, and silencing was more effectively in B biotype than in Q biotype. Feeding dsRNA led to the high mortality in both biotypes, with higher mortality in biotype B (up to 85.88%) than in biotype Q (up to 56.40%). In addition, ability in detoxifying imidacloprid and nicotine was inhibited in dsRNA‐treated adults of both biotypes, more efficiently in biotype B than in biotype Q. Conclusion RNA interference of P450 CYP6CM1 gene decreased gene expression, increased mortality, inhibited ability to detoxify a pesticide or a plant secondary metabolite in both biotypes of B. tabaci, with better efficacy in biotype B than in biotype Q.
      PubDate: 2014-09-08T07:11:31.895312-05:
      DOI: 10.1002/ps.3903
       
  • Model based determination of the influence of textile fabric on bioassay
           analysis and the effectiveness of a textile slow‐release system of
           DEET in mosquito control
    • Authors: Benny Malengier; Tineke Goessens, Flora F. Mafo, Mike De Vrieze, Lieva Van Langenhove, Samuel Wanji, Frederic Lynen
      Pages: n/a - n/a
      Abstract: Background Determining how effective a product is to repel mosquitoes or other flying insects is a difficult task. One approach is using a bioassay with textile fabric. We investigated the role of the textile substrate in the bioassay with a numerical model, and compared with known results for DEET. We next apply the model to determine the effectiveness of textile slow‐release formulations based on coatings, and compare this with a field study in the Cameroon. Slow‐release formulations are difficult to evaluate with standard tests as the compound needs a build up time not present in these tests. Results We found excellent correspondence between the model and the known DEET results without matching parameters. Slow release approaches are deemed possible but have several drawbacks. Modeling can help in identifying optimal use conditions. The field test with a slow release system performed better than the model anticipated with initially more than 90% repellency. DEET coated textile was considered not marketable however. Conclusion We advise that bioassays also characterize more detailed the type of textile fabric used so as to allow drawing conclusions with textile modeling. Concerning coated textile slow release systems, more research is needed. We nevertheless advise usage mainly at entrance points, eg as scrims.
      PubDate: 2014-09-08T07:11:29.860522-05:
      DOI: 10.1002/ps.3902
       
  • Susceptibility to Bt proteins is not required for Agrotis ipsilon aversion
           to Bt maize
    • Authors: Rachel R. Binning; Joel Coats, Xiaoxiao Kong, Richard L. Hellmich
      Pages: n/a - n/a
      Abstract: Background Although Bacillus thuringiensis (Bt) maize has been widely adopted in diverse regions around the world, relatively little is known about the susceptibility and behavioral response of certain insect pests to Bt maize in countries where this maize is not currently cultivated. These are important factors to consider as management plans are developed. These factors were investigated for Agrotis ipsilon, a global pest of maize, with Cry1F and Cry34Ab1/Cry35Ab1 maize. Results Agrotis ipsilon demonstrated an initial, post‐ingestive aversive response to Cry1F maize. Development and mortality were also affected – survival on Cry1F maize tissue was 40% and weight gain of survivors of Cry1F exposure was significantly reduced. A post‐ingestive aversive response was also seen for Cry34Ab1/Cry35Ab1 maize, however longer‐term feeding, weight gain, and survival were not affected. Conclusion Agrotis ipsilon showed aversion to both Bt treatments. Aversion to Cry34Ab1/Cry35Ab1 maize was unexpected because these proteins have no known insecticidal effect against Lepidoptera, however results confirm that this aversion was temporary and did not affect growth or development. The Cry1F results suggest A. ipsilon will abandon Cry1F maize in the field before any selection for resistance. These data support the use of refuge to delay Cry1F resistance development in A. ipsilon populations.
      PubDate: 2014-09-04T03:35:45.148243-05:
      DOI: 10.1002/ps.3901
       
  • Fitness costs of reproductive capacity and ovarian development in a Bt
           resistant strain of the cotton bollworm, Helicoverpa armigera
           (Hübner) (Lepidoptera: Noctuidae)
    • Authors: Wanna Zhang; Long Ma, Feng Zhong, Yanan Wang, Yuyuan Guo, Yanhui Lu, Gemei Liang
      Pages: n/a - n/a
      Abstract: Background The cotton bollworm Helicoverpa armigera has developed resistance to the insecticidal Cry1Ac toxins produced by Bacillus thuringiensis (Bt) in China. To better understand fitness cost associated to resistance evolution, the reproductive capacities and ovarian development were examined in four strains of H. armigera: a Cry1Ac‐susceptible (96S), a Cry1Ac‐resistant fed on an artificial diet with Cry1Ac toxin for 135 generations (BtR), and two strains derived from BtR: a strain grown without Cry1Ac selection for 38 generations (CK1), and a strain grown for one generation without Cry1Ac selection (CK2). Results 96S and CK1 had similar reproductive capacity and Cry1Ac susceptibility. Comparing to 96S and CK1, the fecundity and hatching rate of CK2 decreased more than 30% and 50%, respectively. Moreover, the number of eggs laid by BtR was significantly lower than that by 96S and CK1, but higher than that by CK2. In accordant with the differences of reproductive capacity, ovarian development in CK2 and BtR was significantly delayed. Conclusion These results indicated that there was a fitness cost in the reproductive physiology in the resistant strains. Reversion to susceptibility to the Bt Cry‐toxin in resistant CK1 strain was associated with an increase in reproductive capacity.
      PubDate: 2014-09-03T06:06:16.771038-05:
      DOI: 10.1002/ps.3900
       
  • Design, Synthesis and Herbicidal Activity of Novel
           Quinaoline‐2,4‐diones as 4‐Hydroxyphenylpyruvate
           Dioxygenase Inhibitors
    • Authors: Da‐Wei Wang; Hong‐Yan Lin, Run‐Jie Cao, Ze‐Zhong Ming, Tao Chen, Ge‐Fei Hao, Wen‐Chao Yang, Guang‐Fu Yang
      Pages: n/a - n/a
      Abstract: Backgound 4‐Hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27, HPPD) has been identified as one of the most promising target sites for herbicide discovery. To discover novel HPPD inhibitors with high herbicidal activity and improved crop selectivity, a series of novel triketone‐containing quinazoline‐2,4‐dione derivatives possessing a variety of substituents at the N‐1 position of the quinazoline‐2,4‐dione ring were designed and synthesized. Results The results of in vitro tests and greenhouse experiments indicated that some analogues showed good HPPD inhibitory activity, with promising broad spectrum herbicidal activity at the rate of 150 g ai/ha. Most surprisingly, compound 11h, 1‐ethyl‐6‐(2‐hydroxy‐6‐oxocyclohex‐1‐enecarbonyl)‐3‐(o‐tolyl)quinazoline‐2,4(1H,3H)‐dione, showed the highest HPPD inhibition activity with a Ki value of 0.005 μM, about 2 times more potent than mesotrione (Ki = 0.013 μM). Further greenhouse experiments indicated that compounds 11d and 11h displayed strong and broad‐spectrum post‐emergent herbicidal activity even at a dosage as low as 37.5 g ai/ha, which was superior to mesotrione. More importantly, compounds 11d and 11h were safe for maize at the rate of 150 g ai/ha, and compound 11d was safe for wheat as well. Conclusion The present work indicated that the triketone‐containing quinazoline‐2,4‐dione motif could be a potential lead structure for further development of novel herbicides.
      PubDate: 2014-09-03T06:06:14.31359-05:0
      DOI: 10.1002/ps.3894
       
  • Mosquitocidal Carbamates With Low Toxicity to Agricultural Pests: An
           Advantageous Property For Insecticide Resistance Management
    • Authors: Daniel R. Swale; Paul R. Carlier, Joshua A. Hartsel, Ming Ma, Jeffrey R. Bloomquist
      Pages: n/a - n/a
      Abstract: Background Insecticide resistance in the malaria mosquito, Anopheles gambiae, is well documented and widespread agricultural use of pyrethroids may exacerbate development of resistance when pyrethroids are used in vector control. We have developed carbamate anticholinesterases that possess a high degree of An. gambiae:human selectivity for enzyme inhibition. The purpose of this study was to assess the spectrum of activity of these carbamates against other mosquitoes and agricultural pests. Results Experimental carbamates were potent inhibitors of mosquito acetylcholinesterases, with IC50 values in the nanomolar range. Similar potencies were observed for Musca domestica and Drosophila melanogaster enzymes. Although meta‐substituted carbamates were potent inhibitors, two ortho‐substituted carbamates displayed poor enzyme inhibition (IC50 ≥ 10−6 M) in honey bee (Apis mellifera), Asian citrus psyllid (Diaphorina citri), and lepidopteran agricultural pests (Plutella xylostella and Ostrinia nubilalis). Enzyme inhibition results were confirmed by toxicity studies in caterpillars, where the new carbamates were 2‐ to 3‐fold less toxic than propoxur and up to 10‐fold less active than bendiocarb, indicating little utility of these compounds for crop protection. Conclusion The experimental carbamates were broadly active against mosquito species but not agricultural pests, which should mitigate selection for mosquito insecticide resistance by reducing agricultural uses of these compounds.
      PubDate: 2014-09-03T06:05:40.965703-05:
      DOI: 10.1002/ps.3899
       
  • Mating disruption of Coleophora deauratella (Lepidoptera: Coleophoridae)
           using laminate flakes in red clover seed production fields
    • Authors: Boyd A. Mori; Maya L. Evenden
      Pages: n/a - n/a
      Abstract: Background The red clover casebearer, Coleophora deauratella, is a significant pest in red clover (Trifolium pratense) seed production regions throughout the world. The internal feeding nature of C. deauratella larvae makes infestations difficult to control with insecticide. We test the ability of Hercon Disrupt Micro‐Flakes® releasing the complete pheromone blend of C. deauratella to disrupt communication and mating in red clover seed production fields. Results Initial small‐plot (0.25 ha) trials found a significant reduction (93.6 ± 2.9%) of male C. deauratella captured in pheromone‐treated plots compared to untreated controls. Subsequent large‐plot (5 ha) mating disruption trials found a significant reduction (72.3 ± 5.7 %) in male C. deauratella captured in pheromone‐treated plots compared to untreated control plots over the growing season. Furthermore, larval numbers were significantly reduced and seed yield was increased in pheromone‐treated plots compared to untreated control plots. In a concurrent small‐plot (0.0625 ha) trial with various flake densities, disruption increased with pheromone flake density and the resulting graphical disruption profiles matched the theoretical predictions of mating disruption by competitive attraction. Conclusion Pheromone‐mediated mating disruption with laminate flakes has the potential to suppress C. deauratella populations and may help reduce damage even at high pest densities.
      PubDate: 2014-09-02T03:07:37.555532-05:
      DOI: 10.1002/ps.3898
       
  • Utilizing Next‐Generation Sequencing to Study Homeologous
           Polymorphisms and Herbicide Resistance Endowing Mutations in Poa annua
           Acetolactate Synthase Genes
    • Authors: Shu Chen; J. Scott McElroy, Michael L Flessner, Fenny Dane
      Pages: n/a - n/a
      Abstract: Background Detection of single nucleotide polymorphisms (SNPs) related to herbicide resistance in non‐model polyploid weed species is fraught with difficulty due to the gene duplication and lack of reference sequences. Our research seeks to overcome these obstacles by Illumina HiSeq read mapping, SNP calling and allele frequency determinations. Our focus is on the acetolactate synthase (ALS) gene, the target site of ALS inhibiting herbicides, in Poa annua, an allotetraploid weed species originated from two diploid parents, P. supina and P. infirma. Results ALS contigs with complete coding regions of P. supina, P. infirma, and P. annua were assembled and compared with ALS genes from other plant species. The ALS infirma‐homeolog of P. annua showed higher levels of nucleotide sequence variability than the supina‐homeolog. Comparisons of read mappings of P. annua and a simulated P. supina × P. infirma hybrid showed high resemblance. Two homeolog‐specific primer pairs were designed, and used to amplify a 1860 bp region that covers all resistance‐conferring codons in the ALS gene. Four P. annua populations, GN, RB, GW and LG, showed high resistance to two ALS inhibitors, bispyribac‐sodium and foramsulfuron, and two populations, HD and RS, showed lower resistance in the rate response trial. Mutations conferring Trp‐574‐Leu substitution were observed in the infirma‐homeolog of GN and RB, and supina‐homeolog of GW and LG, but no resistance conferring mutation was observed in the two populations of lower resistance, HD and RS. Conclusion In this study we have demonstrated the use of NGS data to study homeologous polymorphisms, parentage and herbicide resistance in an allotetraploid weed species, P. annua. Complete coding sequences of ALS gene were assembled for P. infirma, P. supina, infirma‐homeolog and supina‐homeolog in P. annua. A pipeline consisted of read mapping, SNP calling and allele frequency calculation was developed to study the parentage of P. annua, which provided a new perspective to look at this topic besides the views of morphology, karyotype and phylogeny. Our two homeolog‐specific primer pairs can be utilized in future research to separate the homeologs of ALS gene in P. annua and cover all the codons that have been reported to confer herbicide resistance.
      PubDate: 2014-09-02T03:05:22.414882-05:
      DOI: 10.1002/ps.3897
       
  • Methiozolin Sorption and Mobility in Sand‐Based Root‐Zones
    • Authors: Michael Luke Flessner; Glenn R Wehtje, Joseph Scott McElroy, Julie A Howe
      Pages: n/a - n/a
      Abstract: Background Methiozolin is a herbicide currently used for annual bluegrass control in golf course putting greens. Previous research indicates that maximum weed control efficacy requires root exposure; however, soil sorption and mobility of methiozolin has not been established. Research was conducted to investigate soil sorption and subsequent desorption by dilution of methiozolin, as well as soil mobility using batch equilibrium experiments and thin‐layer chromatography in nine root‐zones. Evaluations focused on sand‐based systems typical of many golf course putting greens. Results Sorption coefficients (Kd values) ranged from 0.4 to 29.4 mL g−1 and averaged 13.8 mL g−1. Sorption was most influenced by organic matter content; conversely, soil pH had a negligible effect. Methiozolin desorption did not occur with 0.01 M CaCl2 dilution. Methiozolin mobility was low; retardation factors (Rf values) were 
      PubDate: 2014-09-01T03:56:14.640149-05:
      DOI: 10.1002/ps.3896
       
  • Identification of species and geographical strains of Sitophilus oryzae
           and Sitophilus zeamais using VIS/NIR hyperspectral imaging technique
    • Authors: Yang Cao; Chaojie Zhang, Quansheng Chen, Yanyu Li, Shuai Qi, Lin Tian, YongLin Ren
      Pages: n/a - n/a
      Abstract: Background Identifying stored‐product insects is essential for granary management. Automated, computer‐based classification methods are rapidly developing in many areas. A hyperspectral imaging technique could potentially be developed to identify stored‐product insect species and geographical strains. This study tested and adapted the technique using four geographical strains of each of two insect species, the rice weevil and maize weevil to collect and analyze the resultant hyperspectral data. Results Three characteristic images that corresponded to the dominant wavelengths, 505, 659 and 955 nm were selected by multivariate image analysis. Each image was processed and 22 morphological and textural features from regions of interest were extracted as the inputs for an identification model. We found the back propagation neural network model to be the superior method for distinguishing between the insect species and geographical strains. The overall recognition rates of the classification model for insect species were 100% and 98.13% for the calibration and prediction sets respectively, while the rates of the model for geographical strains were 94.17% and 86.88% respectively. Conclusion This study demonstrated that hyperspectral imaging, together with the appropriate recognition method, could provide a potential instrument for identifying insects and could become a useful tool for identification of Sitophilus oryzae and Sitophilus zeamais to aid in the management of stored‐product insects.
      PubDate: 2014-08-29T04:40:11.250973-05:
      DOI: 10.1002/ps.3893
       
  • Dissipation behaviour, processing factors and risk assessment for
           metalaxyl in greenhouse‐grown cucumber
    • Authors: Mohammad Kazem Ramezani; Dariush Shahriari
      Pages: n/a - n/a
      Abstract: BACKGROUND Cucumber is widely cultivated in Iran, and the application of systemic and protective fungicides is the main choice of disease treatment, particularly in greenhouse‐grown systems. In this research, cucumber fruits were harvested at 1 h to 25 days after the last application to determine the residue and dissipation behaviour of metalaxyl. The effects of peeling and storage (at 3 °C for 4 days) on metalaxyl residue reduction were also assessed. Samples were extracted by the QuEChERS procedure then analysed using liquid chromatography–tandem mass spectrometry. RESULTS The dissipation of metalaxyl residues approximately fitted a first‐order kinetic model, obtaining half‐life values of 2.2 and 3.8 days and preharvest interval values of 5.2 and 12.5 days at the recommended dose (2 kg ha−1) and double (4 kg ha−1) dose respectively. The processing factor values for peeling and storage were 0.50 and 0.93 respectively, showing that storage had little effect on residue reduction compared with peeling. CONCLUSION The higher content of metalaxyl residues in flesh showed its penetration from the skin into the flesh. The results provided more understanding of fungicide distribution as well as the effective role of peeling in reducing residues in cucumber fruits. © 2014 Society of Chemical Industry
      PubDate: 2014-08-28T07:11:49.283329-05:
      DOI: 10.1002/ps.3859
       
  • Effect of insecticide treated potato plants on aphid behavior and Potato
           Virus Y acquisition.
    • Authors: Sébastien Boquel; Jianhua Zhang, Claudia Goyer, Marie‐Andrée Giguère, Catherine Clark, Yvan Pelletier
      Pages: n/a - n/a
      Abstract: Background The objective was to assess the effect of two contact insecticides, lambda‐cyhalothrin and flonicamid, and three systemic insecticides, pymetrozine, dimethoate and imidacloprid on the behavior and Potato virus Y acquisition of three aphid species, Macrosiphum euphorbiae (Thomas), Rhopalosiphum padi L. and Aphis fabae (Scopoli). Results One to four days after application, contact insecticides strongly modified aphid behavior and intoxicated them. Dimethoate sprayed on potato plants did not change the behavior of the three tested aphid species while imidacloprid slightly reduced the probing behavior of M. euphorbiae and intoxicated several R. padi. The residual effect of the insecticides (10 to 21 days after application) was almost nonexistent. No intoxication was found and only slight changes in the behavior of R. padi and A. fabae were observed. The acquisition of PVY by R. padi was reduced on lambda‐cyhalothrin and dimethoate treated plants that were sprayed a few days before the test. Conclusion One systemic and two contact insecticides were effective at intoxicating aphids and reducing probing behavior soon after application. Some insecticides might sporadically reduce the spread of PVY either by modifying the behavior or reducing PVY acquisition but their action is likely limited to a short period of time after application.
      PubDate: 2014-08-27T03:11:19.698698-05:
      DOI: 10.1002/ps.3892
       
  • Tetraoxanes as a New Class of Efficient Herbicides Comparable to
           Commercial Products
    • Authors: Raphael C. Cusati; Luiz C. A. Barbosa, Célia R. A. Maltha, Antônio J. Demuner, Alberto Oliveros‐Bastidas, Antônio A. Silva
      Pages: n/a - n/a
      Abstract: Background Several 1,2,4,5‐tetraoxanes were synthesized and their herbicidal activity was tested against weed and compared to commercial herbicides glyphosate and imazethapyr. Results The compounds were prepared by reacting carbonyl compounds with hydrogen peroxide under acid catalysis affording 1,1‐dihydroperoxides (36‐91%) that were further converted into 1,2,4,5‐tetraoxanes (10‐52%) under similar reaction conditions. All products were evaluated against Sorghum bicolor and Cucumis sativus at 0.0125 mM to 1.0 mM and several tetraoxanes caused >70% inhibition on the growth of roots and aerial parts. The most active products were evaluated against the weeds Sorghum arundinaceum, Euphorbia heterophylla, Brachiaria brizantha and Bidens pilosa. Some compounds were highly effective (>80% inhibition at 1.0 mM) against the weeds, showing activity comparable to that of glyphosate or imazethapyr. Also, compound 36 was selective, being inactive against dicotyledonous while inhibiting the roots and aerial parts of monocotyledonous by 92.9‐97.5%, comparable to the effect of glyphosate. Conclusions Tetraoxanes constitute in a new class of effective herbicides with great potential for commercial development.
      PubDate: 2014-08-26T05:23:12.326027-05:
      DOI: 10.1002/ps.3891
       
  • Nematicidal activity of furanocoumarins from parsley against Meloidogyne
           spp.
    • Authors: Pierluigi Caboni; Marco Saba, Chrisostomos Oplos, Nadhem Aissani, Andrea Maxia, Urania Menkissoglu‐Spiroudi, Laura Casu, Nikoletta Ntalli
      Pages: n/a - n/a
      Abstract: Background This report describes activity against Meloidogyne spp. and chemical characterisation of the essential oil and methanol extract of Petroselinum crispum aerial parts. This study was based on the hypothesis that P. crispum could be used as an intercrop and soil amendment in tomato culture for nematode control. Results The methanol extract and the essential oil exhibited significant nematicidal activity against M. incognita, M. hapla and M. arenaria, with the first being the most sensitive species, with EC50/72h of 140 ± 15 and 795 ± 125 mg L−1for the extract and oil, respectively. The most abundant furanocoumarin compounds in the methanolic extract were xanthotoxin, psoralen, bergapten and oxypeucedanin; levels ranged from 1.77 to 46.04 mg kg−1 wet weight. The EC50/24h values of xanthotoxol, psoralen and xanthotoxin against M. incognita were 68 ± 33, 147 ± 88 and 200 ± 21 mg L−1, respectively. Addition of fresh parsley paste to soil reduced the number of M. incognita females and plant galls on tomato roots; EC50 values were 24.79 and 28.07 mg g−1, respectively. Moreover, parsley paste enhanced tomato growth in a dose‐response manner. Conclusions Parsley exhibits promising nematicidal activity as an organic amendment and as a source of nematotoxic furanocoumarins.
      PubDate: 2014-08-26T05:22:26.174923-05:
      DOI: 10.1002/ps.3890
       
  • MOBILITY AND EFFICACY OF ABAMECTIN AND IMIDACLOPRID AGAINST Rhynchophorus
           ferrugineus IN Phoenix canariensis BY DIFFERENT APPLICATION METHODS
    • Authors: Ó. Dembilio; J.M Riba, M. Gamón, J.A. Jacas
      Pages: n/a - n/a
      Abstract: Background Rhynchophorus ferrugineus is the most destructive pest of palms. As detection of early infestation stages is difficult, preventive measures, mostly chemical control, are crucial. Stipe injection of insecticides has developed fast as a suitable technique. However, pesticide movement within palms and palm reaction to wounding remains controversial. We used abamectin and imidacloprid applied by crown spray, stipe and frond injections to disentangle how these pesticides move within P. canariensis and how tissues wounded by injection heal. Furthermore, we established their lethal doses to larvae of R. ferrugineus. Results Maximum residues of imidacloprid (0.1 mg kg−1) were detected in crown and frond samples for up to 2 months after stipe injection whereas maximum residues of abamectin were found in frond tip samples (0.5 mg a.s. kg−1) 5 months after stipe injection. Based on the LCs calculated, these doses could satisfactorily protect palms for up to 3 months after treatment. No significant wound damage was observed 2 years after injection. Conclusion Stipe injection, irrespective of the active substance considered, resulted in better distribution and higher persistence compared with frond injection and, especially, crown spray. As a consequence, our results point at stipe injection as a good alternative to control R. ferrugineus.
      PubDate: 2014-08-25T05:33:13.297953-05:
      DOI: 10.1002/ps.3889
       
  • Bird‐repellents effects on bait efficacy for control of invasive
           mammal pests
    • Authors: Phil Cowan; Sam Brown, Guy Forrester, Lynn Booth, Michelle Crowell
      Pages: n/a - n/a
      Abstract: Background Repellents to reduce crop damage from birds and mammals have been investigated extensively but their efficacy in reducing risk to non‐target birds in aerial poisoning operations for control of mammal pests is less known. We assessed the impact on bait acceptability, palatability and kill efficacy for captive wild rats (Rattus rattus L.) and possums (Trichosurus vulpecula Kerr) of adding bird repellents (anthraquinone and d‐pulegone) to baits used for their control in food choice trials. Results For possums, anthraquinone at 0.25% reduced acceptability and palatability but not the efficacy of poison baits, whereas d‐pulegone at 0.17% had no significant effects. Rats showed little response to d‐pulegone, but developed a marked aversion to prefeed baits containing anthraquinone at both 0.1 and 0.25%, such that almost no exposed rats ate poison baits and mortality was reduced significantly. The aversion induced by anthraquinone was generalised to the bait as anthraquinone‐exposed rats did not eat bait with only d‐pulegone. Conclusion Anthraquinone is not suitable for inclusion in bait for rat control at the concentrations tested, and also presents some risk to efficacy for possum control. D‐pulegone would be suitable for inclusion in bait for possums and rats but problems related to its volatility in bait manufacture and storage would need to be overcome. Further studies should focus on an alternative secondary repellent, or establishing the maximum anthraquinone concentration that does not reduce efficacy for rats and testing whether or not that concentration is sufficient to reliably repel native birds from baits.
      PubDate: 2014-08-21T04:31:49.020158-05:
      DOI: 10.1002/ps.3887
       
  • Absorption, translocation and metabolism of bispyribac‐sodium on
           rice seedlings under cold stress
    • Authors: Luiz Fernando D Martini; Nilda R Burgos, José Alberto Noldin, Luis Antonio Avila, Reiofeli A Salas
      Pages: n/a - n/a
      Abstract: Background Rice production is highly affected by weed competition. The efficacy of chemical weed control and crop safety is a function of absorption, translocation and metabolism of herbicides. This study investigates the effect of cold stress 22/16C (day/night) on absorption, translocation and metabolism of 14C‐bispyribac‐sodium on rice seedlings. Results Maximum 14C‐bispyribac‐sodium absorption occurred at 24 HAT and was stimulated by the warm 30/22C (day/night) temperature. A large amount of total absorbed herbicide was retained in the treated leaf, indicating that bispyribac‐sodium had minimal translocation to other plant parts. Piperonyl‐butoxide, a P450 inhibitor, plus herbicide, caused greater injury than the herbicide alone. In addition, injury on rice plants was enhanced by exposure to cold, emphasizing the negative effect on herbicide metabolism. In the Thin Layer Chromatography metabolism experiment, cold‐grown plants had higher injury and retained more of the parent herbicide than plants grown at a warm temperature. Conclusion Cold stress reduces bispyribac‐sodium absorption and metabolism in rice, but has no effect on translocation.
      PubDate: 2014-08-20T05:21:35.466055-05:
      DOI: 10.1002/ps.3882
       
  • Baseline‐sensitivity of maize borers in India to the Bacillus
           thuringiensis insecticidal proteins Cry1A.105 and Cry2Ab2
    • Authors: S. K. Jalali, Lalitha Y; Rakshit Ojha, Pradyumn Kumar, Suby S. B, Reema Sharma, Rupa Nair, C.Ravi K, S.P. Kamath, S.Mohan K.
      Pages: n/a - n/a
      Abstract: Background Among the major pests of maize in India are two stem borers, Chilo partellus (Swinhoe) and Sesamia inferens (Walker) and an earworm, Helicoverpa armigera (Hübner). As a pest control strategy, transgenic Bacillus thuringiensis (Bt) maize hybrids are undergoing regulatory trials in India. We have determined the sensitivity of the target lepidopterans to the insecticidal Bt proteins expressed in Bt‐maize as this determines product efficacy and the resistance management strategy to be adopted. Maize hybrids with event MON89034 express two insecticidal Bt proteins, Cry1A.105 and Cry2Ab2. Results Sensitivity profiles of 53 populations of C. partellus, 21 of S. inferens and 21 of H. armigera, collected between 2008 and 2013 from maize growing areas in India, to Cry1A.105 and Cry2Ab2 proteins were generated through dose‐response assays. Cry1A.105 protein was the most effective to neonates of C. partellus (mean MIC90 range 0.30 ‐ 1.0 µg mL−1) and H. armigera (mean MIC90 range 0.71 ‐ 8.22 µg mL−1), whereas, Cry2Ab2 (mean MIC90 range 0.65 ‐ 1.70 µg mL−1) was the most effective to S. inferens. Conclusion Populations of C. partellus, S. inferens and H. armigera, were susceptible to the Bt proteins Cry1A.105 and Cry2Ab2. The Bt‐sensitivity data will serve as pre‐commercialization benchmarks for resistance monitoring purposes.
      PubDate: 2014-08-20T05:19:42.308123-05:
      DOI: 10.1002/ps.3888
       
  • Cyantraniliprole: A valuable tool for Frankliniella occidentalis
           (Pergande) management
    • Authors: Pablo Bielza; Juan Guillén
      Pages: n/a - n/a
      Abstract: Background Frankliniella occidentalis is a worldwide economically important pest. Scarcity of effective products and cross‐resistance issues make resistance to existing insecticides a recurring problem that requires the development of new control tools, such as incorporating novel compounds. Lethal effects of cyantraniliprole on adults and larvae from field and insecticide‐resistant populations were evaluated. In addition, the sublethal effects on biological features such as fecundity, fertility, feeding, oviposition and mating were studied. Results Results obtained for larvae produced LC50 values from 33.4 to 109.2 mg L−1, with a low natural variability (3.3‐fold) and a LC50 composite value of 52.2 mg L−1. The susceptibility for adults was 23‐fold lower than for larvae. No evidence of cross‐resistance between cyantraniliprole and established insecticides used against thrips was evident. Relevant sublethal effects of cyantraniliprole were demonstrated including reduced fecundity, fertility, feeding, oviposition and mating success. Conclusion Low variation in susceptibility across contemporary populations of F. occidentalis and a lack of cross‐resistance to other insecticides indicates cyantraniliprole as a potential candidate in rotation programs within an insecticide resistance management strategy. The combined sub‐lethal effect on reproduction will have an important impact in population reduction. Available data indicate that cyantraniliprole is likely to be a valuable tool for managing thrips populations.
      PubDate: 2014-08-19T04:13:23.026991-05:
      DOI: 10.1002/ps.3886
       
  • Cross‐resistance and baseline susceptibility of Mediterranean
           strains of Bemisia tabaci to cyantraniliprole
    • Authors: Carolina Grávalos; Esther Fernández, Ana Belando, Inmaculada Moreno, Caridad Ros, Pablo Bielza
      Pages: n/a - n/a
      Abstract: Background The whitefly Bemisia tabaci Gennadius is a severe pest in many field and greenhouse crops worldwide, and has developed resistance to insecticides from most chemical classes. The ease with which this pest develops resistance makes it essential to incorporate new compounds with different modes of action and no cross‐resistance with those previously used into insecticide resistance management strategies. To that end, the systemic effect of the new diamide cyantraniliprole was tested with multi‐resistant, selected and field populations of Q‐biotype B. tabaci from the Mediterranean area. Results Bioassays with multi‐resistant and laboratory selected populations indicated no cross‐resistance to cyantraniliprole in the B. tabaci strains exhibiting resistance to other insecticides. The LC50 values for nymphs from fourteen field populations varied between 0.011 mg litre−1 and 0.116, a 10.5‐fold natural variability. The LC50 values for adults from three strains ranged from 0.060 to 0.096 mg litre−1. Conclusion These baseline data will be helpful for monitoring future potential shifts in susceptibility to cyantraniliprole in Mediterranean whitefly populations within an IRM program. Cyantraniliprole may play an important role in mitigating insecticide resistance in B. tabaci because of its high efficacy and its lack of cross‐resistance to other insecticides, even in multi‐resistant Q‐biotype populations collected from a highly problematic insecticide‐resistance area.
      PubDate: 2014-08-19T04:13:20.655963-05:
      DOI: 10.1002/ps.3885
       
  • Identification and characterization of multiple glutathione
           S‐transferase genes from the diamondback moth, Plutella xylostella
    • Authors: Xi'en Chen; Ya‐lin Zhang
      Pages: n/a - n/a
      Abstract: Background The diamondback moth (DBM), Plutella xylostella, is one of the most harmful insect pests on crucifer crops worldwide. In this study, 19 cDNA encoding glutathione S‐transferases (GSTs) were identified from the genomic and transcriptomic database for DBM (KONAGAbase) and further characterized. Results Phylogenetic analysis showed that 19 GSTs were classified into six different cytosolic classes, including 4 in delta, 6 in epsilon, 3 in omega, 2 in sigma, 1 in theta, and 1 in zeta. Two GSTs were unclassified. RT‐PCR analysis revealed most GSTs genes were expressed in all developmental stages with relatively higher expression in the larval stages. Six DBM GSTs were expressed at the highest levels in the midgut tissue. Twelve purified recombinant GSTs showed varied enzymatic properties toward CDNB and GSH, whereas rPxGSTo2, rPxGSTz1, and rPxGSTu2 had no activity. Real‐time quantitative PCR revealed that expression levels of 19 DBM GSTs genes were varied and changed after exposure to acephate, indoxacarb, beta‐cypermethrin, and spinosad. PxGSTd3 was significantly overexpressed while PxGSTe3 and PxGSTs2 were significantly down‐regulated by all four insecticide exposures. Conclusion The changes in DBM GSTs gene expression levels exposed to different insecticides indicate they may play individual roles in tolerance to insecticides and xenobiotics.
      PubDate: 2014-08-15T05:59:24.465718-05:
      DOI: 10.1002/ps.3884
       
  • Dealing with transgene flow of crop protection traits from crops to their
           relatives
    • Authors: Jonathan Gressel
      Pages: n/a - n/a
      Abstract: Genes regularly move within species, to/from crops, as well as to their con‐ specific progenitors, feral and weedy forms (‘vertical’ gene flow). Genes occasionally move to/from crops and their distantly related, hardly sexually interbreeding relatives, within a genus or among closely related genera (diagonal gene flow). Regulators have singled out transgene flow as an issue, yet non‐transgenic herbicide resistance traits pose equal problems, which cannot be mitigated. The risks are quite different from genes flowing to natural (wild) ecosystems versus ruderal and agroecosystems. Transgenic herbicide resistance poses a major risk if introgressed into weedy relatives; disease and insect resistance less so. Technologies have been proposed to contain genes within crops (chloroplast transformation, male sterility) that imperfectly prevent gene flow by pollen to the wild. Containment does not prevent related weeds from pollinating crops. Repeated backcrossing with weeds as pollen parents results in gene establishment in the weeds. Transgenic mitigation relies on coupling crop protection traits in a tandem construct with traits that lower the fitness of the related weeds. Mitigation traits can be morphological (dwarfing, no seed shatter) or chemical (sensitivity to a chemical used later in a rotation). Tandem mitigation traits are genetically linked and will move together. Mitigation traits can also be spread by inserting them in multicopy transposons which disperse faster than the crop protection genes in related weeds. Thus, there are gene flow risks mainly to weeds from some crop protection traits; risks that can and should be dealt with. © 2014 Society of Chemical Industry
      PubDate: 2014-08-15T05:36:04.894193-05:
      DOI: 10.1002/ps.3850
       
  • Resmethrin, the First Modern Pyrethroid Insecticide
    • Authors: David M. Soderlund
      Pages: n/a - n/a
      Abstract: The discovery of resmethrin almost five decades ago was the seminal event in the development of pyrethroid insecticides as important pest management tools whose value endures today. This brief review considers the development of pyrethroids from the perspective of the discovery of resmethrin. I describe the pathway to the discovery of resmethrin and the unique properties that differentiated it from the pyrethrins and earlier synthetic pyrethroids. I also summarize information on metabolic fate and mechanisms of selective toxicity, first elucidated with resmethrin, that have shaped our understanding of pyrethroid toxicology since that time. Finally, I review the discovery pathway that led from resmethrin to the development of the first photostable, agriculturally useful pyrethroids that established the importance of this insecticide class.
      PubDate: 2014-08-14T03:20:37.824077-05:
      DOI: 10.1002/ps.3881
       
  • Identification of putative kdr mutations in the tropical bed bug, Cimex
           hemipterus (Hemiptera: Cimicidae).
    • Authors: Kai Dang; Cheryl S. Toi, David G. Lilly, Chow‐Yang Lee, Richard Naylor, Apiwat Tawatsin, Usavadee Thavara, Wenun Bu, Stephen L. Doggett
      Pages: n/a - n/a
      Abstract: Background Bed bugs (both Cimex hemipterus [F.] and Cimex lectularius L.) worldwide are highly resistant to the pyrethroids. An important resistance mechanism known as ‘knockdown resistance’ (kdr) is caused by genetic point mutations on the voltage‐gated sodium channel (VGSC) gene. Previous studies have identified two point mutations (V419L and L925I) on the VGSC gene in C. lectularius that are responsible for kdr‐type resistance. However, the kdr mutations in C. hemipterus have not been investigated. Results Four novel mutations, L899V (leucine to valine), M918I (methionine to isoleucine), D953G (aspartic acid to glycine) and L1014F (leucine to phenylalanine), were identified in the domain II region of the C. hemipterus VGSC gene. This region has been widely investigated for the study of ‘kdr’‐type resistance to the pyrethroids in other insect pests. The V419L and L925I kdr mutations as previously identified in C. lectularius, were not detected in C. hemipterus. Conclusion M918I and L1014F were considered probable kdr mutations and may play essential roles in kdr‐type resistance to pyrethroids in C. hemipterus. Further studies are in process to determinate the non‐kdr type resistance mechanisms in C. hemipterus in our laboratory.
      PubDate: 2014-08-14T03:20:35.818616-05:
      DOI: 10.1002/ps.3880
       
  • Concerted action of target‐site mutations and high EPSPS activity in
           glyphosate‐resistant junglerice (Echinochloa colona) from California
           
    • Authors: Rocío Alarcón‐Reverte; Alejandro García, Susan B. Watson, Ibrahim Abdallah, Sebastián Sabaté, María J. Hernández, Franck E. Dayan, Albert Fischer
      Pages: n/a - n/a
      Abstract: Background Echinochloa colona is an annual weed affecting field crops and orchards in California. An E. colona population carrying a mutation in the EPSPS gene endowing resistance to glyphosate, the most widely used non‐selective herbicide, was recently identified in the Northern Sacramento Valley of California. Plants from this population, from a suspected glyphosate‐resistant (GR) population, and from one susceptible (S) population collected in the Northern Sacramento Valley of California were used to generate three GR and one S selfed lines to study possible mechanisms involved in glyphosate resistance. Results Based on the amount of glyphosate required to kill 50% of the plants (LD50), GR lines were 4‐ to 9‐fold more resistant than S plants and accumulated less shikimate after glyphosate treatment. GR and S lines did not differ in glyphosate absorption, translocation or metabolism. A different target site mutation was found in each of two of the GR lines corresponding to Pro106Thr and Pro106Ser substitutions; the mutations were found in different homoeologous EPSPS genes. No mutation was found in the third GR line, which exhibited 1.4‐fold higher basal EPSPS activity and a 5‐fold greater LD50 than S plants. Quantitative RT‐PCR revealed that GR lines had similar or lower EPSPS expression than S plants. Conclusion We demonstrate that individuals with different glyphosate resistance mechanisms can coexist in the same population, individuals from different populations may carry different resistance mechanisms, and different mechanisms can act in concert within single E. colona plants. However, other plant factors or resistance mechanisms appear to modulate plant expression of EPSPS sensitivity to glyphosate.
      PubDate: 2014-08-13T01:06:41.453335-05:
      DOI: 10.1002/ps.3878
       
  • Transportation Behavior of fluopicolide and its control effect against
           Phytophthora capsici in greenhouse tomatoes after soil application
    • Authors: Lili Jiang; Hongyan Wang, Hui Xu, Kang Qiao, Xiaoming Xia, Kaiyun Wang
      Pages: n/a - n/a
      Abstract: Background Fluopicolide, a novel benzamide fungicide, was registered for control of oomycete pathogens, of which P. capsici is included. In this study, fluopicolide (5% SC) was applied in soil at the rate of 1.5, 3 and 6 L ha−1 (which is normal, double and quadruple dosage respectively) to investigate its transportation behavior and control efficiency on tomato blight as a soil treatment agent. Results The results showed that, soil treated fluopicolide could be absorbed by tomato roots and then transplanted to stems and leaves. It could exist in tomato roots for more than 30 days, and in leaves and stems until the 20th day. The decline discipline of fluopicolide in soil was in accordance with the first order dynamic equation, with half‐lives (t1/2) 5.33, 4.75 and 5.42 d for the ND, DD and QD treatment respectively. The control efficiencies of soil treated fluopicolide were better than spraying applied one, and the inhibition ratios were 93.02%, 97.67% and 100% on the 21st day for the ND, DD and QD treatment respectively. Conclusion Soil application of fluopicolide could control P. capsici in greenhouse tomatoes with high efficiency and long persistence.
      PubDate: 2014-08-12T03:42:54.52326-05:0
      DOI: 10.1002/ps.3879
       
  • Data worth and prediction uncertainty for pesticide transport and fate
           models in Nebraska and Maryland, USA
    • Authors: Bernard T Nolan; Robert W Malone, John E Doherty, Jack E Barbash, Liwang Ma, Dale L Shaner
      Pages: n/a - n/a
      Abstract: Background Complex environmental models frequently are extrapolated to overcome data limitations in space and time, but quantifying data worth to such models is rarely attempted. We determined which field observations most informed the parameters of agricultural systems models applied to field sites in Nebraska (NE) and Maryland (MD), and we identified parameters and observations that most influenced prediction uncertainty. Results The standard error of regression of the calibrated models was about the same at both NE (0.59) and MD (0.58), and overall reductions in prediction uncertainties of metolachlor and metolachlor ethane sulfonic acid concentrations were 98.0 and 98.6 %, respectively. Observation data groups reduced the prediction uncertainty by 55–90 % at NE and 28–96 % at MD. Soil hydraulic parameters were well informed by the observed data at both sites, but pesticide and macropore properties had comparatively larger contributions after model calibration. Conclusions Although the observed data were sparse, they substantially reduced prediction uncertainty in unsampled regions of pesticide breakthrough curves. Nitrate evidently functioned as a surrogate for soil hydraulic data in well‐drained loam soils conducive to conservative transport of nitrogen. Pesticide properties and macropore parameters could most benefit from improved characterization to further reduce model misfit and prediction uncertainty.
      PubDate: 2014-08-06T07:38:34.263931-05:
      DOI: 10.1002/ps.3875
       
  • Efficacy of thiamethoxam and fipronil, applied alone and in combination,
           to control Limonius californicus and Hypnoidus bicolor (Coleoptera:
           Elateridae)
    • Authors: Anuar Morales‐Rodriguez; Kevin W. Wanner
      Pages: n/a - n/a
      Abstract: Background Wireworms, the larval stage of click beetles (Family Elateridae), are significant soil pests of wheat and barley crops in the Pacific Northwest. At present, few pest management alternatives exist. For several decades, wireworms were effectively controlled by first generation insecticides applied to the soil or as seed treatments. Currently used neonicotinoid insecticides protect crop seeds and germinating seedlings by temporary toxicity but limited mortality. As a result, field populations may increase, reaching levels too high for crop protection. In this study we investigated the combination of two insecticides to achieve crop protection as well as insect mortality in wheat fields. Results Laboratory bioassays using wheat seed treated with fipronil at 1.0 and 5.0 grams AI 100 kg−1 of seed resulted in 72‐90% mortality of two wireworm species, Limonius californicus and Hypnoidus bicolor. At a rate of 39 g AI 100 kg−1 kg of seed, eight times higher than the high rate of fipronil, thiamethoxam caused only 10‐31% larval mortality in the bioassays, but did protect developing wheat stands from damage in field trials. Field plots planted with wheat seed treated with both 5.0 g AI of fipronil and 39.0 g AI of thiamethoxam 100 kg−1 of seed had 83% fewer wireworms the following year compared to untreated check plots. No reduction in population was observed in plots treated with 39.0 g of thiamethoxam alone. Conclusions Fipronil and thiamethoxam can be combined as a seed treatment to protect wheat crops from wireworm damage and reduce larval populations in the field.
      PubDate: 2014-08-06T07:37:19.940157-05:
      DOI: 10.1002/ps.3877
       
  • Establishment of multiple pesticide biodegradation capacities from
           pesticide‐primed materials in on‐farm biopurification system
           microcosms treating complex pesticide‐contaminated waste water
    • Authors: Kristel Sniegowski; Dirk Springael
      Pages: n/a - n/a
      Abstract: Background “On farm” biopurification systems (BPS) treat pesticide containing waste water at farms by biodegradation and sorption processes. The inclusion of pesticide‐primed material carrying a pesticide degrading microbial community is beneficial to improve biodegradation but no data exist for treating wastewater containing multiple pesticides as often occurs at farms. In a microcosm setup, it was examined whether multiple pesticides degradation activities could be simultaneously established in the matrix of a BPS, by simultaneous inclusion of different appropriate pesticide‐primed materials. The microcosms were fed with a mixture of pesticides including the fungicide metalaxyl and the herbicides bentazon, isoproturon, linuron and metamitron and pesticide degrading activities were monitored in time. Results The strategy immediately provided the microcosms with a multiple pesticide degradation/mineralization capacity that improved during feeding of the pesticide mixture. Not only the degradation of the parent compound improved but also this of produced metabolites and compound mineralization. The time to achieve maximum degradation/mineralization capacity depended on the pesticide degradation capacity of the pesticide primed materials. Conclusions Our data show that the addition of pesticide‐primed materials into the matrix of a BPS as an approach to improve biodegradation, can be extended towards the treatment of pesticide mixtures.
      PubDate: 2014-08-05T02:10:35.462975-05:
      DOI: 10.1002/ps.3876
       
  • Intensive cropping systems select for greater seed dormancy and increased
           herbicide resistance levels in Lolium rigidum (annual ryegrass)
    • Authors: Mechelle J. Owen; Danica E. Goggin, Stephen B. Powles
      Pages: n/a - n/a
      Abstract: Background Lolium rigidum (annual ryegrass) is a widespread annual crop weed which has evolved high levels of resistance to selective herbicides. Anecdotal evidence suggests that intensive cropping also leads to higher seed dormancy in L. rigidum. This was quantified by measuring dormancy levels in L. rigidum populations collected from paired sites (one with nil to low cropping intensity, the other intensively cropped) located throughout the Western Australian grain belt. Results Populations from non‐cropped fields or those with low cropping intensity showed higher and faster germination than populations from fields with a medium‐ or high‐intensity cropping regime. Resistance to selective herbicides was also higher in the medium‐ and high‐intensity cropping fields than in the low‐intensity cropping fields. Conclusion High‐intensity cropping systems are likely to impose greater selection pressures for seed dormancy and selective herbicide resistance, because late‐emerging seedlings avoid pre‐planting weed control practices (tillage and non‐selective herbicide application) but are exposed to selective in‐crop herbicides.
      PubDate: 2014-08-01T04:05:22.303242-05:
      DOI: 10.1002/ps.3874
       
  • Mating competitiveness and life table comparisons between transgenic and
           Indian wild type Aedes aegypti L.
    • Authors: Prabhakargouda B Patil; Niranjan B P Reddy, Kevin Gorman, Seshu Reddy V K, Shirish R Barwale, Usha B Zehr, Derric Nimmo, Neil Naish, Luke Alphey
      Pages: n/a - n/a
      Abstract: Background OX513A is a genetically‐engineered strain of Ae. aegypti carrying a repressible, dominant inherited transgene that confers lethality in immature heterozygous progeny. Released male OX513A adults have proven effective for the localised suppression of wild Ae. aegypti, highlighting its potential in vector control. Mating and life table assessments were used to compare OX513A with reared Ae. aegypti strains collected from New Delhi and Aurangabad regions in India. Results Mating proportions of New Delhi females versus males of OX513A or New Delhi strains were 0.52 and 0.48 respectively, indicating no discrimination by females against either strain, and males of both strains were equally competitive. Developmental time from first instar to adult emergence was significantly longer for OX513A (10.7 ± 0.04 days) than for New Delhi (9.4 ± 0.04 days) and Aurangabad strains (9.1 ± 0.04 days). Differences in mean longevities, female reproductive parameters and population growth parameters between the strains were non‐significant. Conclusions Present laboratory study demonstrates that, only minor life table variations of limited biological relevance exist between OX513A and Indian Ae. aegypti populations, and males were equally potential for mating competitiveness. Thus results support OX513A strain as a suitable candidate for continued evaluation towards sustainable management of Ae. aegypti populations in India.
      PubDate: 2014-07-31T03:54:20.897985-05:
      DOI: 10.1002/ps.3873
       
  • Effect of insecticidal fusion proteins containing spider toxins targeting
           sodium and calcium ion channels on pyrethroid‐resistant strains of
           peach‐potato aphid (Myzus persicae)
    • Authors: Sheng Yang; Elaine Fitches, Prashant Pyati, John A. Gatehouse
      Pages: n/a - n/a
      Abstract: Background The recombinant fusion proteins Pl1a/GNA and Hv1a/GNA contain the spider venom peptides δ‐amaurobitoxin‐PI1a or ω‐hexatoxin‐Hv1a respectively, linked to snowdrop lectin (GNA). Pl1a targets receptor site 4 of insect voltage‐gated sodium channels (NaCh) while Hv1a targets voltage‐gated calcium channels. Insecticide‐resistant strains of peach‐potato aphid (Myzus persicae) contain mutations in NaCh. The pyrethroid‐resistant "kdr" (794J) and "super‐kdr" (UKO) strains contain mutations at residues L1014 and M918 in the channel α‐subunit respectively, while the "kdr + super‐kdr" strain (4824J), insensitive to pyrethroids, contains mutations at both L1014 and M918. Results Pl1a/GNA and Hv1a/GNA fusion proteins have estimated LC50 values of 0.35 and 0.19 mg ml−1 when fed to wild‐type M. persicae. For insecticide‐resistant aphids, LC50 for the Pl1a/GNA fusion protein increased by 2‐ to 6‐fold, correlating with pyrethroid resistance (wild‐type < kdr < super‐kdr < kdr + super‐kdr strains). In contrast, LC50 for the Hv1a/GNA fusion protein showed limited correlation with pyrethroid resistance. Conclusion Mutations in the sodium channel in pyrethroid‐resistant aphids also protect against a fusion protein containing a sodium channel‐specific toxin, despite differences in ligand‐channel interactions, but do not confer resistance to a fusion protein targeting calcium channels. The use of fusion proteins with differing targets could play a role in managing pesticide resistance.
      PubDate: 2014-07-31T03:45:19.438895-05:
      DOI: 10.1002/ps.3872
       
  • Metabolism of agrochemicals and related environmental chemicals based on
           cytochrome P450s in mammals and plants
    • Authors: Hideo Ohkawa; Hideyuki Inui
      Pages: n/a - n/a
      Abstract: A yeast gene expression system originally established for mammalian cytochrome P450 monooxygenase cDNAs was applied to functional analysis of a number of mammalian and plant P450 species including 11 human P450 species (CYP1A1, CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP2D6, CYP2E1 and CYP3A4). The human P450 species CYP1A1, CYP1A2, CYP2B6, CYP2C18 and CYP2C19 were identified as P450 species metabolizing various agrochemicals and environmental chemicals. CYP2C9 and CYP2E1 specifically metabolized sulfonylurea herbicides and halogenated hydrocarbons, respectively. Plant P450 species metabolizing phenylurea and sulfonylurea herbicides were also identified mainly as CYP71 family, although CYP76B1, CYP81B1 and CYP81B2 metabolized phenylurea herbicides. The transgenic plants expressing these mammalian and plant P450 species were applied to herbicide tolerance as well as phytoremediation of agrochemical and environmental chemical residues. The combined use of CYP1A1, CYP2B6 and CYP2C19 belonging to 2 families and 3 subfamilies covered a wide variety of herbicide tolerance and phytoremediation of these residues. The use of 2,4‐D and bromoxynil induced CYP71AH11 in tobacco seemed to enhance herbicide tolerance and selectivity.
      PubDate: 2014-07-31T02:14:40.571498-05:
      DOI: 10.1002/ps.3871
       
  • Neonicotinoids and bumble bees (Bombus terrestris): Effects on nectar
           consumption in individual workers
    • Authors: Helen M. Thompson; Selwyn Wilkins, Sarah Harkin, Sarah Milner, Keith F A Walters
      Pages: n/a - n/a
      Abstract: Background The objective of this study was to quantify whether the presence of three different neonicotinoid insecticides in sucrose solution: imidacloprid, thiamethoxam or clothianidin results in anti‐feedant effects in individual worker bumble bees (Bombus terrestris) and, if so, whether this effect is reversible if bees are subsequently offered untreated feed. Results Bees exposed to imidacloprid displayed a significant dose‐dependent reduction in consumption at 10 and 100 µg/L which was reversed when untreated feed was offered. No consistent avoidance/antifeedant response to nectar substitute with thiamethoxam was detected at the more field realistic dose rates of 1 and 10 µg/L, and exposure to the very high 100 µg/L dose rate was followed by 100% mortality of experimental insects. At 1 µg clothianidin /L no reduction in food intake was recorded, at 10 µg clothianidin /L reduced consumption was noted and 100% mortality occurred when bees were exposed to rates of 100 µg clothianidin /L. Conclusion This study provides evidence of a direct anti‐feedant effect of imidacloprid and clothianidin in individual bumble bees but highlights that this may be a compound specific effect.
      PubDate: 2014-07-30T03:10:25.857145-05:
      DOI: 10.1002/ps.3868
       
  • Transgenic cry1C or cry2A Rice had no Adverse Impacts on Life‐table
           Parameters and Population Dynamics of the Brown Planthopper, Nilaparvata
           lugens (Hemiptera: Delphacidae)
    • Authors: Zeng‐Bing Lu; Yu‐E Liu, Nai‐Shun Han, Jun‐Ce Tian, Yu‐Fa Peng, Cui Hu, Yu‐Yuan Guo, Gong‐Yin Ye
      Pages: n/a - n/a
      Abstract: Background Transgenic rice producing the insecticidal protein from Bacillus thuringiensis Berliner (Bt) is protected from damage by lepidopteran insect pests. However, one of the main concerns about Bt rice is their potential impacts on non‐target herbivores. In the current study, ecological impacts of two Bt rice lines, T1C‐19 expressing Cry1C protein and T2A‐1 expressing Cry2A protein, on the non‐target herbivore brown planthopper (BPH), Nilaparvata lugens (Stål), were evaluated under laboratory and field conditions. The purpose was to verify whether these Bt rice lines could affect the performance of BPH at individual and population scales. Results Laboratory results showed that most of the fitness parameters (development duration, survival rate, fecundity, fertility, amount of honeydew excreted) of BPH were not significantly affected by two tested Bt rice lines, although the development duration of 4th instar nymphs fed on T1C‐19 was distinctly longer compared with that on T2A‐1 and non‐Bt rice plants. Five life‐table parameters did not significantly differ among rice types. Two‐year field trials also revealed no significant difference in population dynamics of BPH among rice types. Conclusion It is inferred that our tested Bt rice lines will unlikely affect the population growth of BPH as released to farmers in future.
      PubDate: 2014-07-28T05:43:32.536934-05:
      DOI: 10.1002/ps.3866
       
  • Characterization of heteroplasmic status at codon 143 of Botrytis cinerea
           cytochrome b gene using semi‐quantitative AS‐PCR assay
    • Authors: Maki Hashimoto; Yoshinao Aoki, Seiya Saito, Shunji Suzuki
      Pages: n/a - n/a
      Abstract: Background An in‐depth understanding of QoI‐fungicide‐resistant B. cinerea isolates in a vineyard is expected to contribute to the development of an optimum disease management program for the control of grape grey mould. Results We characterized the resistance and structure of cytochrome b gene in B. cinerea collected from a Japanese vineyard. The semi‐quantitative AS‐PCR assay developed in the present study was able to distinguish heteroplasmic status from homoplasmic status at codon 143 of cytochrome b gene in QoI‐fungicide‐resistant B. cinerea from vineyards in Japan. With this assay, we demonstrated that the repeated introduction of QoI fungicide selection pressure increased the ratio of G143A‐mutated cytochrome b genes in B. cinerea isolates. Conclusion We propose that the semi‐quantitative AS‐PCR assay is a reliable tool for the detection of QoI fungicide‐resistant and the evaluation of homoplasmic/heteroplasmic status at codon 143 of cytochrome b gene in B. cinerea isolates.
      PubDate: 2014-07-26T04:36:00.972396-05:
      DOI: 10.1002/ps.3867
       
  • Expanding the SAR of Sulfoxaflor: the Synthesis and Biological Activity of
           N‐Heterocyclic Sulfoximines
    • Authors: Benjamin M. Nugent; Ann M. Buysse, Michael R. Loso, Jon M. Babcock, Timothy C. Johnson, M. Paige Oliver, Timothy P. Martin, Matthias S. Ober, Nneka Breaux, Andrew Robinson, Yelena Adelfinskaya
      Pages: n/a - n/a
      Abstract: Background Sulfoxaflor, a new insect control agent developed by Dow AgroSciences, exhibits broad spectrum control of many sap‐feeding insect pests, including aphids, whiteflies, leafhoppers, planthoppers, and lygus bugs. During the development of sulfoxaflor, SAR exploration of the sulfoximine functional group revealed the nature of the sulfoximine nitrogen substituent significantly affects insecticidal acitivity. As part of the investigation to probe the various electronic, steric and lipophilic parameters at this postion, a series of N‐heterocyclic sulfoximines were synthesized and tested for bioactivity against green peach aphid. Results Using a variety of chemistries, the nitrile substituent was replaced with different substituted 5‐ and 6‐membered heterocycles. The compounds in the series were then tested for insecticidal acitivty against green peach aphid in foliar spray assays. Despite the larger steric demand of these substituents, the resulting N‐heterocyclic sulfoximine analogs displayed good levels of efficacy. In particular, the N‐thiazolyl sulfoximines exhibited the greatest activity, with LC50 values as low as 1 ppm. Conclusions The novel series of N‐heterocyclic sulfoximines helped advance the knowledge of the sulfoxaflor SAR, and demonstrated that the structural requirement for the sulfoximine nitrogen position was not limited to small, electron deficient moeities, but rather was tolerant of larger functionality.
      PubDate: 2014-07-26T03:20:17.125736-05:
      DOI: 10.1002/ps.3865
       
  • Induced resistance by oxidative shifts in pigeonpea (Cajanus cajan L.)
           following Helicoverpa armigera (Hübner) herbivory
    • Authors: Rimaljeet Kaur; Anil K Gupta, Gaurav K Taggar
      Pages: n/a - n/a
      Abstract: BACKGROUND Oxidative responses in leaves, developing seeds and the pod wall of nine pigeonpea genotypes were investigated against Helicoverpa armigera feeding. Out of nine genotypes, four were moderately resistant, three were intermediate and two were moderately susceptible genotypes. RESULTS A significant shift in the oxidative status of pigeonpea following herbivory was depicted by the upregulation of diamine oxidase (DAO), polyamine oxidase (PAO) and lipoxygenase 2 (LOX 2) activities. Polyphenol oxidase (PPO) activity was significantly higher in the infested pod wall and leaves of moderately resistant genotypes than in those of moderately susceptible genotypes. H. armigera infestation markedly enhanced phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) activities in wounded tissues. The decline in ascorbate peroxidase (APX) activity and ascorbate content was lower in moderately resistant genotypes than in moderately susceptible genotypes. A significant decrease in LOX 3 activity was also observed in the infested pod wall of moderately resistant and intermediate genotypes. A lower malondialdehyde (MDA) content and higher proline content of the infested pod wall and developing seeds was observed. Higher activities of PPO, PAL and proline content in leaves of uninfested moderately resistant genotypes could either be an unrelated observation or alternatively could help in identifying H. armigera‐resistant genotypes. CONCLUSION The increase in activities of PPO, DAO, PAO, PAL and TAL and higher proline and lower MDA content upon herbivory suggested their integrated contribution in providing resistance to pigeonpea against H. armigera. © 2014 Society of Chemical Industry
      PubDate: 2014-07-25T08:47:20.138845-05:
      DOI: 10.1002/ps.3851
       
  • Pathogenicity bioassays of isolates of Beauveria bassiana on Rhynchophorus
           ferrugineus
    • Authors: Gabriella Lo Verde; Livio Torta, Vincenzo Mondello, Cesare G Caldarella, Santella Burruano, Virgilio Caleca
      Pages: n/a - n/a
      Abstract: BACKGROUND The control of Rhynchophorus ferrugineus (Olivier), the main palm pest in the Mediterranean Basin, is problematic because of its biology and the current restrictions in many European countries on the use of chemical insecticides in urban areas. Entomopathogenic fungi have been studied as potential biological control agents, but information on their natural incidence is limited. Strains of Beauveria bassiana (Balsamo) Vuillemin were isolated from symptomatic insects collected on dead palms, and their pathogenicity against different instars of R. ferrugineus was evaluated in the laboratory. RESULTS The overall percentage of infected insects found in Canary palms was 7%. In laboratory bioassays, hatching of eggs treated with three different isolates of B. bassiana was 41.2, 26.8 and 29.9%, significantly lower than the control (62.4%). Larvae and adults were treated with a single isolate in two ways: spraying each insect with a conidial suspension or feeding them with fruit portions previously immersed in the same conidial suspension. At the end of the two trials, the mortality of treated larvae was 88 and 92%, and the mean survival time was 10.4 and 11.8 days, significantly different from the control, where no insect died during the trials. Mortality and survival time recorded in either trial on adults did not significantly differ between treatment and control. CONCLUSION This study shows that the pathogenicity of wild isolates of B. bassiana differs among the tested R. ferrugineus instars. The low mortality of treated adults supports their use as vectors of B. bassiana as a potential tool for reducing R. ferrugineus populations. © 2014 Society of Chemical Industry
      PubDate: 2014-07-24T09:48:31.213934-05:
      DOI: 10.1002/ps.3852
       
  • Bait station devices can improve mass trapping performance for the control
           of the Mediterranean fruit fly
    • Authors: Vicente Navarro‐Llopis; Jaime Primo, Sandra Vacas
      Pages: n/a - n/a
      Abstract: Background The use of traps and other attract‐and‐kill devices in pest management strategies to reduce Mediterranean fruit fly populations has proven efficient. Nevertheless, many farmers are concerned about the effect of these devices on the trees where they are hung. Direct field observations have revealed that fruit damage is higher in trees with traps than in trees without them. This work evaluates the efficacy of different types of attract‐and‐kill devices to protect fruit of the single tree where the device is placed in. Results Results suggested that trees with traps had, at least, the same fruit damage than trees without them. When traps were baited with protein hyrolizate, fruit damage was even higher than in trees without traps. However, fruit damage is significantly diminished when efficient bait station devices are used. Conclusion Although mass trapping is able to control fruit fly populations as a control method, trees with some type of traps and baits are more susceptible to fly puncture. However, bait station devices reduce fruit damage in the single trees where they are hung. As a conclusion bait station resulted more efficient in fruit protection as fruit flies are affected as soon as they contact the device. Some recommendations for use of the different attract‐and‐kill devices are discussed.
      PubDate: 2014-07-24T04:36:49.253818-05:
      DOI: 10.1002/ps.3864
       
  • Activity‐temperature relationships in Meligethes aeneus:
           Implications for pest management
    • Authors: Andrew W. Ferguson; Lucy M. Nevard, Suzanne J. Clark, Samantha M. Cook
      Pages: n/a - n/a
      Abstract: Background Pollen beetle (Meligethes aeneus F.) management in oilseed rape (Brassica napus L.) has become an urgent issue in the light of insecticide resistance. Risk prediction advice has relied upon flight temperature thresholds while risk assessment uses simple economic thresholds. However, there is variation in the reported temperature of migration and economic thresholds vary widely across Europe; probably due to climatic factors interacting with beetle activity and plant compensation for damage. The effect of temperature on flight, feeding and oviposition activity of M. aeneus was examined in controlled conditions. Results Escape from a release vial was taken as evidence of flight and was supported by video observations. The propensity to fly followed a sigmoid temperature‐response curve between 6–23 °C; 10%, 25% and 50% flight temperature thresholds were 12.0–12.5 °C, 13.6–14.2 °C and 15.5–16.2 °C, respectively. Thresholds were slightly higher in the second of two flight bioassays, suggesting an effect of beetle age. We found strong positive relationships between temperature (6–20 °C) and the rates of feeding and oviposition on flower buds of oilseed rape. Conclusion These temperature relationships could be used to improve M. aeneus migration risk assessment, refine weather‐based decision support systems and modulate damage thresholds according to rates of bud damage.
      PubDate: 2014-07-23T03:54:14.749329-05:
      DOI: 10.1002/ps.3860
       
  • Perspectives on Transgenic, Herbicide‐Resistant Crops in the USA
           Almost 20 Years after Introduction
    • Authors: Stephen O. Duke
      Pages: n/a - n/a
      Abstract: Herbicide‐resistant crops have had profound impacts on weed management. Most of the impact has been by glyphosate‐resistant maize, cotton, soybean, and canola. Significant economic savings, yield increases, and more efficacious and simplified weed management resulted in widespread adoption of the technology. Initially, glyphosate‐resistant crops enabled significantly reduced tillage and reduced the environmental impact of weed management. Continuous use of glyphosate with glyphosate‐resistant crops over broad areas facilitated the evolution of glyphosate‐resistant weeds, which have resulted in increases in the use of tillage and other herbicides with glyphosate, reducing some of the initial environmental benefits of glyphosate‐resistant crops. Transgenic crops with resistance to auxinic herbicides, as well as to herbicides that inhibit acetolactate synthase, acetyl‐CoA carboxylase, and hydroxyphenylpyruvate dioxygenase, stacked with glyphosate and/or glufosinate resistance, will become available in the next few years. These technologies will provide additional weed management options for farmers, but will not have all of the positive impacts (reduced cost, simplified weed management, lowered environmental impact, and reduced tillage) that glyphosate‐resistant crops had initially. In the more distant future, other herbicide‐resistant crops (including non‐transgenic ones), herbicides with new modes of action, and technologies that are currently in their infancy (e.g., bioherbicides, sprayable herbicidal RNAi, and/or robotic weeding) may impact the role of transgenic, herbicide‐resistant crops in weed management.
      PubDate: 2014-07-23T03:39:08.764241-05:
      DOI: 10.1002/ps.3863
       
  • Detection of knockdown resistance (kdr) mutations in the Common bed bug,
           Cimex lectularius (Hemiptera: Cimicidae) in Australia.
    • Authors: Kai Dang; Cheryl S. Toi, David G. Lilly, Wenjun Bu, Stephen L. Doggett
      Pages: n/a - n/a
      Abstract: Background Pyrethroid resistance in the Common bed bug, Cimex lectularius L. has been reported worldwide. An important resistant mechanism is via knockdown resistance (kdr) mutations, notably V419L and L925I. Information regarding this kdr‐type resistant mechanism is unknown in Australia. This study aims to examine the status of kdr mutations in Australian C. lectularius strains. Results Several modern field‐collected strains and museum preserved reference collections of Australian C. lectularius were examined. Of the field strains (2007–2013), 96% had the known kdr‐mutations (L925I or both V419L/L925I). The ‘Adelaide’ strain (2013), and samples from the preserved reference collections (1994–2004), revealed no known kdr‐mutations. A novel mutation I936F was apparent in the insecticide‐resistant ‘Adelaide’ strain, one strain from Perth (with L925I), and the majority of the reference collection specimens. The laboratory insecticide‐resistant ‘Sydney’ strain showed a mixture of no kdr‐mutations (20%) and L925I (80%). Conclusion The novel mutation, I936F may be a kdr‐mutation but appeared to contribute less resistance to the pyrethroids than the V419L and L925I mutations. The detection of high frequencies of kdr mutations indicates that kdr‐type resistance is widespread across Australia. Hence, there should be a reduced reliance on pyrethroid insecticides and an integrated management approach for the control of C. lectularius infestations.
      PubDate: 2014-07-21T04:59:12.864813-05:
      DOI: 10.1002/ps.3861
       
  • Physiological Effects of Temperature on Turfgrass Tolerance to
           Amicarbazone
    • Authors: Jialin Yu; Patrick E. McCullough, Timothy Grey
      Pages: n/a - n/a
      Abstract: Background Amicarbazone effectively controls annual bluegrass (Poa annua L.) in bermudagrass (Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt‐Davy) and tall fescue (Festuca arundinacea Schreb.) with spring applications, but summer applications may excessively injure tall fescue. The objective of this research was to investigate physiological effects of temperature on amicarbazone efficacy, absorption, translocation, and metabolism in annual bluegrass, bermudagrass, and tall fescue. Results At 25/20 ºC (day/night), annual bluegrass absorbed 58 and 40% more foliar applied amicarbazone than bermudagrass and tall fescue, respectively, after 72 h. Foliar absorption increased at 40/35 ºC in all species, compared to 25/20 ºC, and tall fescue had similar absorption to annual bluegrass at 40/35 ºC. At 6 DAT, annual bluegrass metabolized 54% of foliar applied amicarbazone, while bermudagrass and tall fescue metabolized 67 and 64%, respectively. Conclusion Tall fescue is more tolerant to amicarbazone than annual bluegrass at moderate temperatures (≈25/20 ºC) due to less absorption and greater metabolism. However, tall fescue susceptibility to amicarbazone injury at high temperatures (40/35 ºC) results from enhanced herbicide absorption compared to lower temperatures (25/20 ºC). Bermudagrass is more tolerant to amicarbazone than annual bluegrass and tall fescue due to less herbicide absorption, regardless of temperature.
      PubDate: 2014-07-18T04:50:23.156623-05:
      DOI: 10.1002/ps.3853
       
  • Laboratory and field assessment of cyantraniliprole relative to existing
           fly baits
    • Authors: Amy C Murillo; Alec C Gerry, Nicola T Gallagher, Nyles G Peterson, Bradley A Mullens
      Pages: n/a - n/a
      Abstract: BACKGROUND Toxic fly baits are commonly used for fly control in California animal operations. However, resistance development has been a problem. Comprehensive laboratory and field studies were conducted to test commercial baits (imidacloprid, methomyl, dinotefuran, spinosad) and one novel cyantraniliprole bait. A susceptible Musca domestica strain was compared with wild‐type M. domestica and Fannia canicularis strains in the laboratory using choice/no‐choice tests. Field visitation to baits and both short‐ and longer‐term mortality were documented. RESULTS Susceptible Musca suffered high mortality with all baits after 3 days of choice and no‐choice tests. Wild‐type Musca mortality was more variable and higher in no‐choice relative to choice tests. Fannia were most susceptible to spinosad > dinotefuran = cyantraniliprole > methomyl = imidacloprid. Field Musca were most attracted to spinosad > cyantraniliprole > dinotefuran > sugar > methomyl > imidacloprid. Delayed mortality from bait‐fed field flies (captured and held with untreated food and water for 3 days) was ranked spinosad = cyantraniliprole > dinotefuran = methomyl > imidacloprid > sugar. CONCLUSION Behavioral resistance of M. domestica to imidacloprid and methomyl persists. Spinosad and cyantraniliprole baits (delayed mortality) performed best. Speed of action may be a factor in use and misuse of baits. © 2014 Society of Chemical Industry
      PubDate: 2014-07-15T10:22:23.135631-05:
      DOI: 10.1002/ps.3847
       
  • Development of multi‐functional metabolic synergists to suppress the
           evolution of resistance against pyrethroids in insects that blood feed on
           humans
    • Authors: Melissa C. Hardstone; Joseph P. Strycharz, Junheon Kim, Il‐Kwon Park, Kyong Sup Yoon, Young Joon Ahn, Laura C. Harrington, Si Hyeock Lee, J. Marshall Clark
      Pages: n/a - n/a
      Abstract: Background Pyrethroids are the insecticides of choice when exposure to humans is likely, such as occurs in vector‐ and public health‐related control programs. Unfortunately, the pyrethroids share a common resistance mechanism with DDT, knockdown resistance (kdr), and prior extensive use of DDT has predisposed the pyrethroids to cross‐resistance via kdr. Given the widespread occurrence of kdr, the use of synergists with pyrethroids is considered prudent to guard against the selection of multiply‐resistant insects. Results 3‐phenoxybenzyl hexanoate (PBH) was synthesized as a multi‐functional pyrethroid synergist that besides being a surrogate substrate for sequestration/hydrolytic carboxylesterases now also functions as a substrate for oxidative xenobiotic metabolism. Addition of PBH to permethrin‐treated females of the ISOP450 strain of Culex pipiens quinquefasciatus resulted in a 3‐fold increase in synergism as judged by the synergistic ratio. Similarly, PBH synergized the action of deltamethrin by 6‐fold on females of the common bed bug, Cimex lectularius, and was 2.8‐fold more synergistic than piperonyl butoxide (PBO). Conclusions PBH synergized the action of both type I and II pyrethroids in a mosquito vector (Cx. p. quinquefasciatus) and in a public health pest, C. lectularius, respectively, indicating a broad spectrum of action on blood‐feeding insects. PBH appears to have residual properties similar to permethrin and is itself non‐toxic, unlike PBO, and therefore should be compatible with existing pyrethroid formulations used for ITNs and home/residential sprays.
      PubDate: 2014-07-14T13:23:55.018539-05:
      DOI: 10.1002/ps.3856
       
  • Prospects for control of apple leaf midge Dasineura mali (Diptera:
           Cecidomyiidae) by mass trapping with pheromone lures
    • Authors: Peter L Lo; James TS Walker, D Max Suckling
      Pages: n/a - n/a
      Abstract: Background Apple leaf midge, Dasineura mali (Kieffer), poses quarantine issues for some apple export markets because larvae occasionally pupate in the stem end and calyx of fruit. Pheromone‐baited oil‐filled containers in 1‐ha orchard plots trapped adult male D. mali to test the potential for mass trapping to reduce populations. Results Mass trapped plots had 97% fewer adult males in pheromone traps and 48% fewer larvae per shoot in the second D. mali generation compared with untreated areas. Oil traps caught on average 900,000 D. mali per plot over 11 weeks during the second and third generations. Catches averaged 9200/trap at plot corners. By comparison, catches were 51% lower 10–25 m away along borders, 80% lower at the midpoint of borders and 95% lower >7 m from plot edges. Fruit infestation was low (4/8000 apples). Conclusion The attractiveness of the pheromone, monophagous habit and low mobility of D. mali enhance the prospects for successful mass trapping. Countering this are high populations, multi‐voltinism and aspects of mating behaviour. Mass trapping would probably be more effective had it been in place season‐long and conducted over successive years. It needs refinements and more study before becoming a feasible control option for D. mali.
      PubDate: 2014-07-14T13:23:48.85129-05:0
      DOI: 10.1002/ps.3857
       
  • Protection of winter wheat against orange wheat blossom midge,
           Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae): efficacy of
           insecticides and cultivar resistance
    • Authors: Sandrine Chavalle; Florence Censier, Gilles San Martin y Gomez, Michel De Proft
      Pages: n/a - n/a
      Abstract: Background In 2012 and 2013, Sitodiplosis mosellana (Géhin) flights occurred during the susceptible phase of wheat development in Belgium. The protection against this midge afforded by various insecticides was assessed in infested fields on four winter wheat cultivars (susceptible or resistant, and early or late heading). Results The insecticides sprayed at the right time reduced the number of larvae in the ears by 44‐96%, depending on the product. For Julius, the cultivar (cv.) most exposed to S. mosellana in 2013, the mean yield gain resulting from insecticide use was 1,558 kg ha−1 (18%). In the same year, insecticide use resulted in a yield gain of 780 kg ha−1 (8%) for the cv. Lear, despite its resistance to this pest. The link between yield and number of larvae counted in the ears was a logarithmic relationship, suggesting an important reduction in yield caused either by the damage inflicted by young larvae which died at the start of their development or by the activation of costly reactions in plants. Conclusion The study showed that, in cases of severe attack, the timely application of insecticide treatments can protect wheat against S. mosellana and that even resistant cultivars can benefit from these treatments.
      PubDate: 2014-07-11T03:04:20.412309-05:
      DOI: 10.1002/ps.3855
       
  • Mode of action analysis for pesticide‐induced rodent liver tumours
           involving activation of the constitutive androstane receptor: relevance to
           human cancer risk
    • Authors: Brian G. Lake; Roger J. Price, Thomas G. Osimitz
      Pages: n/a - n/a
      Abstract: A number of non‐genotoxic chemicals including some pesticides have been shown to increase the incidence of liver tumours in rats and/or mice. Frameworks for analysing the modes of action (MOAs) by which chemicals produce liver tumours in rodents and the relevance of such tumour data for human risk assessment have now been established. One common MOA for rodent liver tumour formation by non‐genotoxic chemicals involves activation of the constitutive androstane receptor (CAR). Key and associative events for a CAR activation MOA include receptor activation, liver hypertrophy, induction of cytochrome P450 enzyme activities, increased replicative DNA synthesis, altered hepatic foci and liver tumours. While some effects of rodent CAR activators can be observed in human liver, a major species difference is that, unlike rodents, CAR activators do not increase replicative DNA synthesis in human hepatocytes. The CAR activation MOA for rodent liver tumour formation is thus not plausible for humans and hence such compounds do not pose a hepatocarcinogenic hazard for humans.
      PubDate: 2014-07-07T12:17:38.560237-05:
      DOI: 10.1002/ps.3854
       
  • Mating disruption of Spilonota ocellana and other apple orchard tortricids
           using a multispecies reservoir dispenser
    • Authors: Mario Porcel; Patrick Sjöberg, Weronika Swiergiel, Robert Dinwiddie, Birgitta Rämert, Marco Tasin
      Pages: n/a - n/a
      Abstract: BACKGROUND A new mating disruption formulation for population control of a wide range of tortricid pests, including Spilonota ocellana, was tested in Swedish apple orchards during 2012–2013. Owing to the characteristics of the local agricultural landscape, mating disruption was evaluated in isolated orchards rather than through an area‐wide approach. Parameters such as trap shutdown, communication disruption in field cages, damage level and dispenser emission were measured as efficacy indicators. RESULTS The test formulation reduced the catches in monitoring traps for the entire range of the tested species. In field cages, communication between sexes was disrupted for both Adoxophyes orana and Cydia pomonella. The fruit damage caused by leafrollers (including S. ocellana) was reduced by the treatment. The device showed a constant release of all components for the entire flight activity period of these pests. CONCLUSION Single‐orchard experiments showed a significant effect on field populations of the leafroller species complex. While promising, in light of the variability of the result, field scouting may be required to enable practitioners to estimate the density of the pests and avoid possible unexpected attacks. Additional experiments are needed to evaluate the efficacy of the product against C. pomonella. © 2014 Society of Chemical Industry
      PubDate: 2014-07-03T03:35:23.851273-05:
      DOI: 10.1002/ps.3844
       
  • Assessment of soybean injury from glyphosate using airborne multispectral
           remote sensing
    • Authors: Yanbo Huang; Krishna N Reddy, Steven J Thomson, Haibo Yao
      Pages: n/a - n/a
      Abstract: BACKGROUND Glyphosate drift onto off‐target sensitive crops can reduce growth and yield and is of great concern to growers and pesticide applicators. Detection of herbicide injury using biological responses is tedious, so more convenient and rapid detection methods are needed. The objective of this research was to determine the effects of glyphosate on biological responses of non‐glyphosate‐resistant (non‐GR) soybean and to correlate vegetation indices (VIs) derived from aerial multispectral imagery. RESULTS Plant height, shoot dry weight and chlorophyll (CHL) content decreased gradually with increasing glyphosate rate, regardless of weeks after application (WAA). Accordingly, soybean yield decreased by 25% with increased rate from 0 to 0.866 kg AI ha−1. Similarly to biological responses, the VIs derived from aerial imagery – normalized difference vegetation index, soil adjusted vegetation index, ratio vegetation index and green NDVI – also decreased gradually with increasing glyphosate rate, regardless of WAA. CONCLUSION The VIs were highly correlated with plant height and yield but poorly correlated with CHL, regardless of WAA. This indicated that indices could be used to determine soybean injury from glyphosate, as indicated by the difference in plant height, and to predict the yield reduction due to crop injury from glyphosate. Published2014.Thisarticle is a U.S.Government work and is in the public domainin the USA.
      PubDate: 2014-06-27T07:35:14.849598-05:
      DOI: 10.1002/ps.3839
       
  • Impact of Bacillus amyloliquefaciens S13‐3 on control of bacterial
           wilt and powdery mildew in tomato
    • Authors: Shoko Yamamoto; Soma Shiraishi, Yumi Kawagoe, Mai Mochizuki, Shunji Suzuki
      Pages: n/a - n/a
      Abstract: BACKGROUND Biological control is a non‐hazardous technique to control plant diseases. Researchers have explored microorganisms that show high plant‐disease control efficiency for use as biological control agents. RESULTS A single soil application of Bacillus amyloliquefaciens strain S13‐3 suppressed tomato bacterial wilt caused by Ralstonia solanacearum, a soilborne bacterial pathogen, through production of antibiotics augmented possibly by induction of systemic acquired resistance. Soil application also controlled tomato powdery mildew disease through induction of systemic acquired resistance. CONCLUSION S13‐3 showing bifunctional activity with a single application to soil may be an innovative biological control agent against bacterial wilt and powdery mildew in tomato. © 2014 Society of Chemical Industry
      PubDate: 2014-06-27T07:35:09.577814-05:
      DOI: 10.1002/ps.3837
       
  • Female detection of the synthetic sex pheromone contributes to the
           efficacy of mating disruption of the European grapevine moth, Lobesia
           botrana
    • Authors: Ally R Harari; Tirtza Zahavi, Hadass Steinitz
      Pages: n/a - n/a
      Abstract: BACKGROUND Studies of the mechanisms by which mating‐disruption techniques control insect pest populations have traditionally focused on the effects of the species‐specific sex pheromone on the male moths, while neglecting possible direct effects of the pheromone on females. Here, the effects of exposure to synthetic species‐specific sex‐pheromone on Lobesia botrana (European grapevine moth) females were tested. RESULTS Females in vineyards that were treated with mating‐disruption pheromone burst into short bouts of flying more frequently, but called significantly less frequently than females in untreated plots. Reduced calling caused by exposure to the species‐specific sex‐pheromone may increase the age at which females mate and thereby reduce female fecundity. Females that called in a pheromone‐saturated environment experienced a decrease in number of oviposited eggs. A further decrease in reproductive success may occur if females delay oviposition when exposed to access of the synthetic pheromone. CONCLUSIONS In addition to reducing the ability of males to locate females, the mating‐disruption technique can suppress pest numbers as a consequence of its direct effects on females. The two mechanisms probably act synergistically. © 2014 Society of Chemical Industry
      PubDate: 2014-06-26T05:07:35.147814-05:
      DOI: 10.1002/ps.3830
       
  • Detection of genetically isolated entities within the Mediterranean
           species of Bemisia tabaci: new insights into the systematics of this
           worldwide pest
    • Authors: Laurence Mouton; Olivier Gnankiné, Hélène Henri, Gabriel Terraz, Guillaume Ketoh, Thibaud Martin, Frédéric Fleury, Fabrice Vavre
      Pages: n/a - n/a
      Abstract: BACKGROUND The taxonomy of the species complex Bemisia tabaci, a serious agricultural pest worldwide, is not well resolved yet, even though species delimitation is critical for designing effective control strategies. Based on a threshold of 3.5% mitochondrial (mtCOI) sequence divergence, recent studies have identified 28 putative species. Among them, mitochondrial variability associated with particular symbiotic compositions (=cytotypes) can be observed, as in MED, which raises the question of whether it is a single or a complex of biological species. RESULTS Using microsatellites, an investigation was made of the genetic relatedness of Q1 and ASL cytotypes that belong to MED. Samples of the two cytotypes were collected in West Africa where they live in sympatry on the same hosts. Genotyping revealed a high level of differentiation, without evidence of gene flow. Moreover, they differed highly in frequencies of resistance alleles to insecticides, which were much higher in Q1 than in ASL. CONCLUSION Q1 and ASL are sufficiently reproductively isolated for the introgression of neutral alleles to be prevented, suggesting that they are actually different species. This indicates that nuclear genetic differentiation must be investigated within groups with less than 3.5% mtCOI divergence in order to elucidate the taxonomy of B. tabaci at a finer level. Overall, these data provide important information for pest management. © 2014 Society of Chemical Industry
      PubDate: 2014-06-26T05:07:31.694501-05:
      DOI: 10.1002/ps.3834
       
  • Biofumigation with Brassica juncea, Raphanus sativus and Eruca sativa for
           the Management of Field Populations of the Potato Cyst Nematode Globodera
           pallida
    • Authors: B. M. Ngala; P.P.J. Haydock, S. Woods, M. A. Back
      Pages: n/a - n/a
      Abstract: Background The viability of potato cyst nematode (PCN) populations (Globodera pallida) was evaluated in three field experiments using Brassica juncea, Raphanus sativus and Eruca sativa amendments. These species were summer-cultivated and autumn-incorporated in Experiment-1; in Experiment-2, overwintered brassicaceous cover crops were spring-incorporated. Experiment-3 involved determination of effects of metconazole application on biomass/glucosinolate production by B. juncea and R. sativus and on PCN pre- and post-incorporation. Glucosinolate contents were determined before incorporation. Following cover crop incorporation, field plots were planted with susceptible potatoes to evaluate the biofumigation effects on PCN reproduction. Results In Experiment-1, PCN population post-potato harvest was reduced (P = 0.03) in B. juncea-treated plots, while R. sativus prevented further multiplication, but in Experiment-2, there were no significant effects on PCN reproduction. In Experiment-3, B. juncea or R. sativus either untreated or treated with metconazole reduced PCN populations. Glucosinolate concentrations varied significantly between different plant regions and cultivation seasons. Metconazole application increased sinigrin concentration in B. juncea tissues. Glucosinolate concentrations correlated positively with PCN mortality for summer-cultivated brassicaceous plants. Conclusion Our results demonstrated that Brassica juncea and Raphanus sativus green manures can play an important role in PCN management, particularly if included in an integrated pest management scheme.
      PubDate: 2014-06-25T12:28:43.11758-05:0
      DOI: 10.1002/ps.3849
       
  • Manipulating behaviour with substrate-borne vibrations – potential
           for insect pest control
    • Authors: J Polajnar; A Eriksson, A Lucchi, G Anfora, M Virant-Doberlet, V Mazzoni
      Pages: n/a - n/a
      Abstract: This review presents an overview of potential use of substrate-borne vibrations for the purpose of achieving insect pest control in the context of integrated pest management. Although the importance of mechanical vibrations in the life of insects has been fairly well established, the effect of substrate-borne vibrations has historically been understudied, in contrast to sound sensu stricto. Consequently, the idea of using substrate-borne vibrations for pest control is still in its infancy. Our review therefore focuses on theoretical background, using it to highlight potential applications in field environment, and lists the few preliminary studies that have been or are being performed. We also note conceptual similarities with the use of sound, as well as limitations inherent in this approach.
      PubDate: 2014-06-24T12:43:32.834097-05:
      DOI: 10.1002/ps.3848
       
  • Insecticide resistance and cross‐resistance development in Colorado
           potato beetle Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae)
           populations in Canada 2008–2011
    • Authors: Ian M Scott; Jeff H Tolman, Dale C MacArthur
      Pages: n/a - n/a
      Abstract: BACKGROUND A survey of insecticide resistance in over 150 Canadian populations of Colorado potato beetle was completed between 2008 and 2011. Three neonicotinoid and two anthranilic diamide insecticides were tested at a discriminating concentration (DC) with second‐instar larvae in a leaf‐disc bioassay. RESULTS The mean mortality for the imidacloprid (Admire) DC was 46–67% between 2008 and 2011 respectively. Over the 4 years, 10–46% and 26–40% of the populations were classified as resistant or showed reduced susceptibility to imidacloprid. The mean mortality for thiamethoxam (Actara) and clothianidin (Poncho/Titan) ranged from 56–76% in 2008 to 81–84% in 2010 for each insecticide respectively, indicating continuous susceptibility to clothianidin but reduced susceptibility to thiamethoxam. In 2008 and 2009, susceptibility to chlorantraniliprole (Coragen) was observed in 85% of populations. Similarly, cyantraniliprole (Cyazypyr) affected 93% of the 2009 and 74% of the 2010 populations. There was a significant (P < 0.05) and high positive correlation (R = 0.4–0.84) between the three neonicotinoids, indicating the potential for cross‐resistance. CONCLUSIONS The trend observed in decreasing susceptibility for thiamethoxam and clothianidin will continue unless resistance management practices are followed. [[ArtCopyrightmsg]]
      PubDate: 2014-06-24T00:58:26.950133-05:
      DOI: 10.1002/ps.3833
       
  • Biopesticides – towards increased consumer safety in the
           European Union
    • Authors: Katarzyna Czaja; Katarzyna Góralczyk, Paweł Struciński, Agnieszka Hernik, Wojciech Korcz, Maria Minorczyk, Monika Łyczewska, Jan K Ludwicki
      Pages: n/a - n/a
      Abstract: The introduction of new food safety regulations in the European Union has resulted in the withdrawal of many synthetic active substances used in plant protection products, in light of their potential or actual harmful effect on human and animal health, as well as on the environment. Alternatives to these compounds are being developed – naturally occurring pesticides, also referred to as biopesticides. The use of biopesticides in crop protection leads to decreased levels of pesticide residues in foods, and as a result to lower risk levels for the consumer. Biologically active agents defined as biopesticides are varied, and therefore application of the same environmental and consumer safety criteria to all of them is impossible. This presents serious complications in the approval of these pesticides as active plant protection products and in their registration. It needs to be stressed that, in the registration procedure of the European Union, biopesticides are subject to the same regulations as synthetic active substances. This situation has resulted in the need to introduce numerous new provisions in the legislation, as well as the preparation of new guidelines facilitating the registration of biopesticides. These activities aim to promote naturally originating pesticides. © 2014 Society of Chemical Industry
      PubDate: 2014-06-19T09:57:47.907691-05:
      DOI: 10.1002/ps.3829
       
  • Frequency of V1016I and F1534C mutations in the voltage-gated sodium
           channel gene in Aedes aegypti of Venezuela.
    • Authors: Leslie C. Alvarez; Gustavo Ponce, Karla Saavedra, Beatriz Lopez, Adriana E. Flores
      Abstract: Background The V1016I and F1534C mutations in the voltage-gated sodium channel gene have been associated with resistance to pyrethroids and DDT in Aedes aegypti mosquitoes. In this study, we determined the frequency of I1016 and C1534 by real time PCR in five natural populations of Ae. aegypti in Venezuela during 2008, 2010 and 2012, as well as in a strain selected with 0.14 µg of deltamethrin for 15 generations. Results In natural populations, frequencies of I1016 varied between 0.01 and 0.37; and for C1534 between 0.35 and 1.0. In Pampanito strain, the frequency of I1016 increased from 0.02 in F1 up to 0.5 in F15 and from 0.35 up to fixation for C1534 after selection with deltamethrin. Conclusion Our results showed that C1534 frequencies are higher in natural populations of Ae. aegypti in Venezuela compared with I1016 and that deltamethrin selected the C1534 more rapidly than I1016.
      PubDate: 2014-06-17T04:02:52.048232-05:
      DOI: 10.1002/ps.3846
       
  • Estimating development of the fennel aphid, Hyadaphis foeniculi
           (Passerini) (Hemiptera: Aphiididae) using nonlinear models
    • Authors: J. B. Malaquias; F.S. Ramalho, A.C.S. Lira, F.Q. Oliveira, F.S. Fernandes, J.C. Zanuncio, W.A.C. Godoy
      Abstract: Background Nonlinear models allowing us to predict agricultural pest outbreaks and optimize control tactics are of primary importance for Integrated Pest Management. The development period for immature stages of Hiadaphis foeniculi (Passerini) (Hemiptera: Aphididae) at constant temperatures was modeled in order to determine mathematical functions for simulating the aphid's development. Nonlinear models were used to describe the relationship between temperature and development rates H. foeniculi subjected to constant temperatures. Results The models used were found to be good fits for estimating H. foeniculi development rates as a function of temperature, with the exception of the Davidson model. The development time of H. foeniculi nymphs ranged from 2.73 days (1st instar) to 6.18 days (4th instar) at 15 °C, 2.57 days (1st instar) to 4.52 days (4th instar) at 20 °C and 1.53 days (1st instar) to 2.05 days (4th instar) at 28 °C. Conclusion These models provide important tools for better elucidating the relationship between temperature and development rates in H. foeniculi. The results could be used for predicting the occurrence of the various immature stages of H. foeniculi in the fennel crop in Brazil, allowing us to more accurately predict the best periods for implementing pest control.
      PubDate: 2014-06-13T15:20:31.095013-05:
      DOI: 10.1002/ps.3845
       
  • Evidence for trade‐offs in detoxification and chemosensation gene
           signatures in Plutella xylostella
    • Authors: Ma Anita M Bautista; Binny Bhandary, Asela J Wijeratne, Andrew P Michel, Casey W Hoy, Omprakash Mittapalli
      Pages: n/a - n/a
      Abstract: BACKGROUND Detoxification genes have been associated with insecticide adaptation in the diamondback moth, Plutella xylostella. The link between chemosensation genes and adaptation, however, remains unexplored. To gain a better understanding of the involvement of these genes in insecticide adaptation, the authors exposed lines of P. xylostella to either high uniform (HU) or low heterogeneous (LH) concentrations of permethrin, expecting primarily physiological or behavioral selection respectively. Initially, 454 pyrosequencing was applied, followed by an examination of expression profiles of candidate genes that responded to selection [cytochrome P450 (CYP), glutathione S‐transferase (GST), carboxylesterase (CarE), chemosensory protein (CSP) and odorant‐binding protein (OBP)] by quantitative PCR in the larvae. Toxicity and behavioral assays were also conducted to document the effects of the two forms of exposure. RESULTS Pyrosequencing of the P. xylostella transcriptome from adult heads and third instars produced 198 753 reads with 52 752 486 bases. Quantitative PCR revealed overexpression of CYP4M14, CYP305B1 and CSP8 in HU larvae. OBP13, however, was highest in LH. Larvae from LH and HU lines had up to five‐ and 752‐fold resistance levels respectively, which could be due to overexpression of P450s. However, the behavioral responses of all lines to a series of permethrin concentrations did not vary significantly in any of the generations examined, in spite of the observed upregulation of CSP8 and OBP13. CONCLUSION Expression patterns from the target genes provide insights into behavioral and physiological responses to permethrin and suggest a new avenue of research on the role of chemosensation genes in insect adaptation to toxins. © 2014 Society of Chemical Industry
      PubDate: 2014-06-13T06:01:27.648373-05:
      DOI: 10.1002/ps.3822
       
  • Structure–activity relationship studies of the phytotoxic properties
           of the diterpenic moiety of breviones
    • Authors: Ceferino Carrera; Nuria Chinchilla, Frank R Fronczek, Juan CG Galindo, Francisco A Macías
      Pages: n/a - n/a
      Abstract: BACKGROUND Brevianes are a family of bioactive meroterpenoids originally described in fungi of the family Penicillium. These compounds have attracted a great deal of interest not only because of their unusual skeleton, suggesting a mixed mevalonate and polyketide biogenetic pathway, and their unusual oxa‐spiro ring fused to an α‐pyrone, but also because of the bioactivities shown by many members of this family. RESULTS During the course of a project aimed at the total synthesis of natural breviones A to E, the authors were able to synthesise the diterpenic moiety of brevianes and abeo‐brevianes. As a result, a collection of 25 compounds were synthesised and tested for bioactivity by two different bioassays. The bioassays used were etiolated wheat coleoptiles (Triticum aestivum) and seedlings in petri dishes. The plant species tested in the seedling bioassay were the commercial dicots lettuce and cress and the monocot weeds Echinochloa crus‐galli and Lolium rigidum. CONCLUSIONS The results clearly show that expanded phenanthrene‐like compounds corresponding to the diterpenic moiety of abeo‐brevianes are more selective towards E. crus‐galli in comparison with L. rigidum. Such selectivity can reach up to one order of magnitude (200‐fold) and makes some of the compounds good candidates as leads for the development of more specific herbicides. [[ArtCopyrightmsg]]
      PubDate: 2014-06-11T08:06:24.328344-05:
      DOI: 10.1002/ps.3831
       
  • Upregulation of probing‐ and feeding‐related behavioural
           frequencies in Bemisia tabaci upon acquisition of Tomato yellow leaf curl
           virus
    • Authors: SM Hemayet Jahan; Gwan‐Seok Lee, Sukchan Lee, Kyeong‐Yeoll Lee
      Pages: n/a - n/a
      Abstract: BACKGROUND The behaviour of insect vectors can be altered by the acquisition of plant viruses. Bemisia tabaci, which is the vector of Tomato yellow leaf curl virus (TYLCV), causes damage to susceptible tomato cultivars. Here, the frequencies of several behavioural characteristics related to probing and feeding that are exhibited by non‐viruliferous (NV) and TYLCV‐viruliferous (V) adult B. tabaci were compared using a sandwich‐type parafilm cage. RESULTS The frequencies of behaviours such as wing flapping, leg movement, body shaking and body position change while settling and feeding on plant leaves were higher in V than in NV whiteflies. Evaluation of probing frequencies by measuring the number and size of holes punctured in parafilm by whiteflies revealed that most holes had a diameter of 7.5–26.7 µm, which is within the range of proboscis diameters of whiteflies. There were more small‐sized holes than medium‐ and large‐sized holes. Male whiteflies produced more small‐sized holes, but females more mid‐sized holes. V whiteflies showed increased hole numbers but decreased feeding duration relative to NV whiteflies. CONCLUSION Adult B. tabaci showed higher frequencies of probing and feeding behaviours when infected with TYLCV. These manipulations of feeding behaviours of insect vectors may result in increased transmission of plant virus. © 2014 Society of Chemical Industry
      PubDate: 2014-06-11T04:12:34.056326-05:
      DOI: 10.1002/ps.3828
       
  • A novel bioassay to monitor fungicide sensitivity in Mycosphaerella
           fijiensis
    • Authors: Josué E Ngando; Adrien Rieux, Oscar Nguidjo, Luc Pignolet, Cécile Dubois, Andreas Mehl, Marie‐Françoise Zapater, Jean Carlier, Luc de Lapeyre de Bellaire
      Pages: n/a - n/a
      Abstract: BACKGROUND Black leaf streak disease (BLSD) is the most important disease of bananas for export. The successful control of BLSD requires an intensive use of systemic fungicides, leading to the build‐up of resistance and failure of control. Early detection of fungicide resistance is crucial to drive rational chemical strategies. Present methods relying on ascospore germination bioassays have several drawbacks that could be overcome using conidia. RESULTS Generally, a single genotype is present on the conidial population derived from one lesion. Conidial germination tests with thiabendazole (5 mg L−1) enable a clear detection of strains resistant to methyl benzimidazole carbamates. Germination bioassays on azoxystrobin (10 mg L−1) enable the detection of most QoI‐resistant strains, but their proportion might be underestimated with cut‐off limits of germ tube length (L > 120 µm) or growth inhibition (GI < 50%). The level of fungicide resistance differs at different canopy levels of a banana tree, which should be considered for sampling. The ascospore germination bioassay provided more variable estimations of the level of resistance by comparison with the new conidial germination bioassay. CONCLUSION Germination bioassays performed with conidia obtained from young lesions overcome most drawbacks encountered with ascospore germination bioassays and could be considered as a new reference method for fungicide resistance monitoring in this species. Different steps are proposed, from sampling to microscopic examinations, for the implementation of this technique. © 2014 Society of Chemical Industry
      PubDate: 2014-06-11T04:11:38.138868-05:
      DOI: 10.1002/ps.3825
       
  • Toxicity of hiba oil constituents and spray formulations to American house
           dust mites and copra mites
    • Authors: Jun-Ran Kim; Haribalan Perumalsamy, Min Jung Kwon, Se Um Chae, Young-Joon Ahn
      Abstract: Background Dermatophagoides farinae and Tyrophagus putrescentiae are recognized as an important source of allergens. An assessment was made of the toxicity of hiba, Thujopsis dolabrata var. hondai, oil and 13 organic compounds and the control efficacy of four experimental spray formulations containing the oil (5–30 g L−1 sprays) against both mite species. Results In a contact + fumigant mortality bioassay, (−)-thujopsene was the most toxic constituent against D. farinae and T. putrescentiae (24 h LC50, 9.82 and 10.92 µg/cm2) and the toxicity of the compound was nearly identical to that of benzyl benzoate (9.33 and 10.14 µg/cm2). The toxicity was more pronounced in carvacrol, (+)-terpinen-4-ol, β-thujaplicin, (−)-terpinen-4-ol, cedrol and α-terpineol (LC50, 12.05–15.20 and 12.74–16.48 µg/cm2) than N,N-diethyl-3-methylbenzamide (LC50, 35.53 and 38.42 µg/cm2) against both mite species. The hiba oil 30 g L−1 spray and commercial permethrin (cis:trans, 25:75) 2.5 g L−1 spray treatment resulted in 100 and 11% mortality against both mite species respectively. In vapour-phase mortality tests, the two compounds were consistently more toxic in closed versus open containers, indicating that toxicity was achieved mainly through the action of vapour. Conclusion Reasonable mite control in indoor environments can be achieved by spray formulation containing the 30 g L−1 hiba oil as potential contact-action fumigants.
      PubDate: 2014-06-10T12:01:26.485344-05:
      DOI: 10.1002/ps.3843
       
  • The Red Queen in a potato field: integrated pest management versus
           chemical dependency in Colorado potato beetle control
    • Authors: Andrei Alyokhin; David Mota‐Sanchez, Mitchell Baker, William E Snyder, Sandra Menasha, Mark Whalon, Galen Dively, Wassem F Moarsi
      Pages: n/a - n/a
      Abstract: Originally designed to reconcile insecticide applications with biological control, the concept of integrated pest management (IPM) developed into the systems‐based judicious and coordinated use of multiple control techniques aimed at reducing pest damage to economically tolerable levels. Chemical control, with scheduled treatments, was the starting point for most management systems in the 1950s. Although chemical control is philosophically compatible with IPM practices as a whole, reduction in pesticide use has been historically one of the main goals of IPM practitioners. In the absence of IPM, excessive reliance on pesticides has led to repeated control failures due to the evolution of resistance by pest populations. This creates the need for constant replacement of failed chemicals with new compounds, known as the ‘insecticide treadmill’. In evolutionary biology, a similar phenomenon is known as the Red Queen principle – continuing change is needed for a population to persevere because its competitors undergo constant evolutionary adaptation. The Colorado potato beetle, Leptinotarsa decemlineata (Say), is an insect defoliator of potatoes that is notorious for its ability to develop insecticide resistance. In the present article, a review is given of four case studies from across the United States to demonstrate the importance of using IPM for sustainable management of a highly adaptable insect pest. Excessive reliance on often indiscriminate insecticide applications and inadequate use of alternative control methods, such as crop rotation, appear to expedite evolution of insecticide resistance in its populations. Resistance to IPM would involve synchronized adaptations to multiple unfavorable factors, requiring statistically unlikely genetic changes. Therefore, integrating different techniques is likely to reduce the need for constant replacement of failed chemicals with new ones. © 2014 Society of Chemical Industry
      PubDate: 2014-06-06T03:34:59.499857-05:
      DOI: 10.1002/ps.3826
       
  • Design, synthesis and insecticidal activity of novel
           1,1‐dichloropropene derivatives
    • Authors: Jun Li; Zhen‐Yu Wang, Qiong‐You Wu, Guang‐Fu Yang
      Pages: n/a - n/a
      Abstract: BACKGROUND Pyridalyl is a highly active insecticide against lepidopterous larvae, with a novel chemical structure not related to any other existing insecticide. To discover new pyridalyl analogues with high activity against resistant pests, a series of 1,1‐dichloropropene derivatives bearing structurally diverse substituted heterocycle rings in place of the pyridine ring of pyridalyl were designed and synthesised. RESULTS All of the title compounds were confirmed by 1H NMR, 13C NMR and high‐resolution mass spectra. Two representative compounds (Ic and IIa) were further characterised by X‐ray diffraction analysis. In addition, bioassays showed that most of the newly synthesised compounds displayed good insecticidal activity against Prodenia litura. Further determination of LD50 values and field trials identified compound IIa as the most promising candidate, which produced a much better 14 day control effect against diamondback moths and longer duration of efficacy than pyridalyl, indicating its potential for further development as a new insecticide for the control of lepidopteran insects. CONCLUSION Compound IIa has great potential for further development as a new insecticide for the control of lepidopteran insects. © 2014 Society of Chemical Industry
      PubDate: 2014-06-05T07:35:09.882866-05:
      DOI: 10.1002/ps.3827
       
  • Polyenylcyclopropane carboxylic esters with high insecticidal activity
    • Authors: Claudia Ferroni; Lucio Bassetti, Valerio Borzatta, Elisa Capparella, Carlotta Gobbi, Alberto Guerrini, Greta Varchi
      Abstract: Background Pyrethroids are synthetic derivatives of naturally occurring pyrethrum. These molecules are widely used in agriculture for ant, flies and mosquito control and for lawn and garden care. Pyrethroids are the optically active esters of 2,2-dimethyl-3-(2-methylpropenyl)-cyclopropane carboxylic acid, also known as chrysanthemic acid. However, their intense use resulted in the development of resistance in many insect species. We report herein specific structural modifications of pyrethroids’ scaffold and their effect on insecticidal activity, especially on resistant pests strains. Results The exposure to (1R)-trans-(E/Z)-2,3,5,6-tetrafluorobenzyl-3-(buta-1,3-dienyl)-2,2-dimethyl cyclopropanecarboxylate and its diastereomers, produced 100% mortality in yellow fever mosquitoes (Aedes aegypti), house mosquitoes (Culex quinquefasciatus) and houseflies (Musca domestica). Besides, this compound provided a complete knockdown (KT100) within 15 minutes of exposure against cockroaches (Blattella germanica) and maintained an excellent knockdown activity after 10 days from treatment. Conclusion In conclusion, we describe novel pyrethroid derivatives obtained from 2,2-dimethyl-3-(2-methylpropenyl)-cyclopropanecarboxylic acid, which display high insecticidal activity, a wide spectrum of action and no toxicity towards mammalians. Moreover, the described synthetic procedures are highly efficient and inexpensive, therefore suitable for industrial scale-up.
      PubDate: 2014-06-05T04:23:01.59148-05:0
      DOI: 10.1002/ps.3842
       
  • Enantioselective bioaccumulation and toxic effects of fipronil in the
           earthworm Eisenia foetida following soil exposure
    • Authors: Fang Qin; Yongxin Gao, Peng Xu, Baoyuan Guo, Jianzhong Li, Huili Wang
      Abstract: Background Enantiomers of chiral pesticides often have different bioactivity, toxicity, and environmental behaviors. Fipronil has been used in racemate for agricultural purposes against soil insects, leading to increased inputs into soil environments and complex biota exposures. To understand the potential risk associated with fipronil enantiomers exposure, subchronic toxicity and bioaccumulation tests with earthworms (Eisenia foetida) in fipronil-spiked soils were evaluated under laboratory condition. Results Enantioselective toxicity was measured in E. foetida biomass after 28-days of subchronic exposure, with increased toxicity from racemate and S-fipronil compared with R-fipronil. The bioaccumulation of fipronil in earthworm tissues was also enantioselective with a preferential accumulation of S-fipronil and the enantiomer fraction were approximately 0.56-0.60. During the soil exposure, fipronil was transformed primarily into fipronil sulfide, sulfone, and amide, and E. foetida rapidly accumulated fipronil and sulfone. Conclusion This work points out the enantioselective subchronic toxicity and bioaccumulation of enantiomers of fipronil in E. foetida. The earthworm tissues exhibited a relative enrichment of fipronil and fipronil sulfone, and these compounds might biomagnify (with a biota-to-soil accumulation factor ≥1.0 kgOC kglip−1) allowing for the possible trophic transfer and/or bioaccumulation of all these chemicals if earthworms were consumed by predator organisms.
      PubDate: 2014-06-05T03:20:13.493968-05:
      DOI: 10.1002/ps.3841
       
  • Population management of Rock Hyraxes (Procavia capensis) in residential
           areas
    • Authors: Roelof E Wiid; Hennie J B Butler
      Abstract: Background Frequent reports of rock hyrax (Procavia capensis) invasions in residential areas led to the investigation of this problem as well as identification of possible solutions. From these reports, problem areas in South Africa were identified and sites within the Free State Province were selected for this study. At these sites populations demonstrate an unusual annual increase. This increase led to a food and habitat shortage forcing individuals into residential areas in search of additional refuges and food sources. In order to manage populations, several preventive as well as control methods were assessed and implemented. Population densities were determined using the Lincoln Index and the Robson-Whitlock Technique. Wild populations were included in the study for comparison purposes. Results Additional resources within residential areas supported populations to grow much larger and some exceeded the natural limits, 30 to 40 individuals, by 470%. This influx contributes to human-wildlife conflict. With the use of relocation populations were reduced within three months. Discussion Preventive methods showed various levels of success. Specific combinations of these methods proved more successful than others. To capture and relocate individuals, in order to rapidly decrease a population, was successful. Preliminary results show that establishing relocated populations was not successful due to high predation rates. The reintroduction of natural predators for rock hyrax population control seemed successful but will have to be monitored in a regular basis.
      PubDate: 2014-06-04T12:40:18.964669-05:
      DOI: 10.1002/ps.3840
       
  • Neonicotinoid Concentrations in Arable Soils After Seed Treatment
           Applications in Preceding Years
    • Authors: Ainsley Jones; Paul Harrington, Gordon Turnbull
      Abstract: Background Concentrations of the neonicotinoid insecticides clothianidin, thiamethoxam and imidacloprid were determined in arable soils from a variety of locations in England Results In soil samples taken from the central area of fields, concentrations of clothianidin ranged from 0.02 µg/kg to 13.6 µg/kg. Thiamethoxam concentrations were between
      PubDate: 2014-05-29T03:53:42.43197-05:0
      DOI: 10.1002/ps.3836
       
  • Quantifying the past and future impact of climate on outbreak patterns of
           bank voles (Myodes glareolus)
    • Authors: Christian Imholt; Daniela Reil, Jana A. Eccard, Daniela Jacob, Nils Hempelmann, Jens Jacob
      Abstract: Background Central European outbreak populations of the bank vole (Myodes glareolus Schreber) are known to cause damage in forestry and to transmit the most common type of Hantavirus (Puumala virus, PUUV) to humans. A sound estimation of potential effects of future climate scenarios on population dynamics is prerequisite for long-term management strategies. Historic abundance time series were used to identify the key weather conditions associated with bank vole abundance, and extrapolated to future climate scenarios to derive potential long-term changes in bank vole abundance dynamics. Results Classification and regression tree analysis revealed the most relevant weather parameters associated with high and low bank vole abundances. Summer temperatures two years prior to trapping had the highest impact on abundance fluctuation. Extrapolation of the identified parameters to future climate conditions revealed an increase of years with high vole abundance. Conclusion Key weather pattern associated with vole abundance reflect the importance of superabundant food supply through masting on the occurrence of bank vole outbreaks. Due to changing climate these outbreaks are predicted to potentially increase in frequency 3-4 fold by the end of this century. This may negatively affect damage patterns in forestry and the risk of human PUUV infection in the long-term.
      PubDate: 2014-05-29T03:46:26.92273-05:0
      DOI: 10.1002/ps.3838
       
  • Susceptibility of Tuta absoluta (Lepidoptera: Gelechiidae) Brazilian
           populations to ryanodine receptor modulators
    • Authors: Mateus R. Campos; Tadeu B. M. Silva, Wellington M. Silva, Jefferson E. Silva, Herbert A. A. Siqueira
      Abstract: Background Phthalic and anthranilic diamides comprise a new insecticide class recently registered in Brazil to control Lepidoptera such as the Tuta absoluta (Meyrick). Therefore, the baseline of susceptibility was determined for eight representative field populations of this species to establish a resistance monitoring program. The potential of cross-resistance as well as detoxification metabolism were assessed to fine-tune the resistance management program. Results Brazilian populations were very susceptible to chlorantraniliprole (LC50s varied from 3.17 to 29.64 µg AI L−1), cyantraniliprole (LC50s varied from 8.61 to 28.95 µg AI L−1), and flubendiamide (LC50s varied from 94 to 230 µg AI L−1) with respective resistance ratios of 9.33-, 3.36-, and 2.45- times between most susceptible and tolerant populations. Anthranilic diamides showed significant correlations between logarithm LC50 values among themselves, suggesting a high risk of cross-resistance. However, the logarithm LC50s of T. absoluta to phthalic diamide did not show any correlation with anthranilic diamides. Cytochrome P450-dependent monooxygenase activity showed a weak correlation with logarithm LC50 values of T. absoluta populations to anthranilic diamides, which suggests a potential route for evolving resistance to anthranilic diamides. Conclusion The diamides were highly effective against T. absoluta with populations showing a homogeneous response to them. Cross-resistance is highly expected between anthranilic diamides in T. absoluta. Populations of this pest may evolve resistance by increasing cytochrome P450–dependent monooxygenases.
      PubDate: 2014-05-24T05:36:42.25946-05:0
      DOI: 10.1002/ps.3835
       
  • Synthesis and antifungal evaluation of a series of maleimides
    • Authors: Xiao-Long Chen; Li-Jun Zhang, Fu-Ge Li, Yong-Xian Fan, Wei-Ping Wang, Bao-Ju Li, Yin-Chu Shen
      Abstract: Backgound Maleimides, both natural and synthesized, have good biological activities. In our continuous effort to discover new maleimides with good antifungal activities, we have synthesized a series of 3, 4-dichloro-, 3-methyl and non-substituted maleimides based on the previous studies. The compounds were biologically evaluated against the fungal pathogen Sclerotinia sclorotiorum. Results 25 of 63 compounds had interesting inhibitory potency with EC50 < 10 µg/mL. Among evaluated compounds, N-(3,5-dichlorophenyl)-3,4-dichloromaleimide (EC50= 1.11 µg/mL) and N-octyl-3-methylmaleimide (EC50 = 1.01 µg/mL) were more potent than the commercial fungicides dicloran (EC50=1.72 µg/mL). The results showed that compounds exhibiting LogP values within the range 2.4-3.0 displayed the best results in terms of fungicidal activity and it seemed, therefore, to be the optimal range for this physicochemical parameter. Conclusion The present work demonstrates that some maleimides can be used as potential lead compounds for developing novel antifungal agents against S. sclerotiorum.
      PubDate: 2014-05-05T09:02:11.958935-05:
      DOI: 10.1002/ps.3824
       
  • Development of an Efficient Trapping System for New Zealand Flower Thrips,
           Thrips obscuratus
    • Authors: Warwick J Allen; Vanessa J Mitchell, Kate Colhoun, Bernie A Attfield, Mailee E Stanbury, David M Suckling, Ashraf M El-Sayed
      Abstract: Background New Zealand flower thrips (NZFT), Thrips obscuratus (Crawford), is an economic pest of various horticultural crops in New Zealand and is recognised as a quarantine pest globally. We investigated two chemical attractants (ethyl nicotinate and 6-pentyl-2H-pyran-2-one), three dispensers, three trap designs, and four trap heights to determine the most effective method for monitoring NZFT. Phenology of NZFT at two locations was compared. Results 6-pentyl-2H-pyran-2-one in a polyethylene bag dispenser was the most attractive lure formulation, and exhibited high stability in release rate trials. There was no difference in NZFT catch between vertical panel and cross panel traps, but both caught significantly more than delta traps. However, both types of panel trap had unacceptably high by-catch of native insects. Catch of thrips increased with height from zero to three metres. Phenology of NZFT showed similar population trends at both locations, but with a timing difference of around 50 days. Conclusions Delta traps containing 6-pentyl-2H-pyran-2-one in a polyethylene bag at two metres above the ground is the recommended method for monitoring NZFT, significantly improving the sensitivity, accuracy, and labour input compared to prior methods. Long-term monitoring of NZFT could lead to more accurate economic damage thresholds and timing for when to apply insecticides.
      PubDate: 2014-05-05T09:01:25.390567-05:
      DOI: 10.1002/ps.3823
       
  • Phosphine resistance in Australian Cryptolestes species (Coleoptera:
           Laemophloeidae): Perspectives from mitochondrial DNA Cytochrome Oxidase I
           analysis
    • Authors: Wee Tek Tay; Stephen J. Beckett, Paul J. De Barro
      Pages: n/a - n/a
      Abstract: Background The flat grain beetles (FGB) species Cryptolestes ferrugineus, C. pusillus, C. pusilloides, and C. turcicus are major stored products pests worldwide, of which the first three are present in Australia. C. ferrugineus is also a species with high phosphine resistance status in various countries. Morphological identification of Cryptolestes species is difficult and represents an additional barrier to effectively manage phosphine resistance in FGB. Result Mitochondrial DNA cytochrome oxidase I (mtDNA COI) gene characterisation enabled differentiation of the four major FGB pest species through direct sequence comparison, and enabled the development of a PCR‐RFLP method for rapid species differentiation. We detected two mtDNA haplotypes (Cunk‐01, 02) present at low frequencies with an average nucleotide divergence rate of 0.079 ± 0.011 (s.e.) from C. pusillus. This nucleotide divergence rate is similar to that between C. ferrugineus and C. pusilloides (0.088 ± 0.012). Male and female genitalia morphologies of the Cunk‐02 individuals indicated they were consistent with C. pusillus yet DNA sequence analyses suggested species‐level divergence. The mtDNA COI gene of phosphine bioassayed (at 720ppm; 1mg/L) lab‐reared F1 generation survivors supported the presence of strong phosphine resistance in C. ferrugineus, but unexpectedly also in C. pusilloides and C. pusillus F1 survivors. Conclusion We demonstrated the utility of molecular DNA techniques for differentiating closely related insect species, and its usefulness in assisting the management of pest insect species. The likely presence of a cryptic C. pusillus species in Australia and the possible development of strong phosphine resistance in Australian FGB pest species require further investigation.
      PubDate: 2014-04-21T04:29:26.937952-05:
      DOI: 10.1002/ps.3805
       
  • Insights: The First International Whitefly Symposium
    • Authors: Emmanouil Roditakis; Anastasia Tsagkarakou, John Vontas
      Pages: 1437 - 1437
      PubDate: 2014-09-19T04:17:55.824338-05:
      DOI: 10.1002/ps.3869
       
  • Whitefly Special Issue organized in two parts
    • Authors: Ralf Nauen; Murad Ghanim, Isaac Ishaaya
      Pages: 1438 - 1439
      PubDate: 2014-09-19T04:18:00.955042-05:
      DOI: 10.1002/ps.3870
       
  • Indigenous American species of the Bemisia tabaci complex are still
           widespread in the Americas
    • Authors: Leonardo da F Barbosa; Julio M Marubayashi, Bruno R De Marchi, Valdir A Yuki, Marcelo A Pavan, Enrique Moriones, Jesús Navas‐Castillo, Renate Krause‐Sakate
      Pages: 1440 - 1445
      Abstract: Bemisia tabaci is a complex of at least 36 putative cryptic species. Since the late 1980s, the Middle East–Asia Minor 1 species (MEAM1, formerly known as the B biotype), has emerged in many tropical and subtropical regions of the world and in some areas has displaced the indigenous populations of B. tabaci. Based on analysis of the mtCOI gene, two indigenous species native to America have been reported: New World (NW, formerly the A biotype) and New World 2 (NW2). NW is present at least in Argentina, Brazil, Martinique, Mexico, Texas and Venezuela, and NW2 in Argentina, Bolivia and Brazil. Wild plants (Euphorbia sp. and Ipomoea sp.), as well as important crops such as tomato, bean and cotton, are still hosts for native B. tabaci populations in the Americas. MEAM1 has not completely displaced the native B. tabaci from the Americas. © 2014 Society of Chemical Industry
      PubDate: 2014-03-04T05:45:18.271797-05:
      DOI: 10.1002/ps.3731
       
  • Biology and management of Bemisia whitefly vectors of cassava virus
           pandemics in Africa
    • Authors: James P Legg; Rudolph Shirima, Lensa S Tajebe, Devid Guastella, Simon Boniface, Simon Jeremiah, Elibariki Nsami, Patrick Chikoti, Carmelo Rapisarda
      Pages: 1446 - 1453
      Abstract: Cassava mosaic disease and cassava brown streak disease are caused by viruses transmitted by Bemisia tabaci and affect approximately half of all cassava plants in Africa, resulting in annual production losses of more than $US 1 billion. A historical and current bias towards virus rather than vector control means that these diseases continue to spread, and high Bemisia populations threaten future virus spread even if the extant strains and species are controlled. Progress has been made in parts of Africa in replicating some of the successes of integrated Bemisia control programmes in the south‐western United States. However, these management efforts, which utilise chemical insecticides that conserve the Bemisia natural enemy fauna, are only suitable for commercial agriculture, which presently excludes most cassava cultivation in Africa. Initiatives to strengthen the control of B. tabaci on cassava in Africa need to be aware of this limitation, and to focus primarily on control methods that are cheap, effective, sustainable and readily disseminated, such as host‐plant resistance and biological control. A framework based on the application of force multipliers is proposed as a means of prioritising elements of future Bemisia control strategies for cassava in Africa. © 2014 Society of Chemical Industry
      PubDate: 2014-05-21T04:05:02.483151-05:
      DOI: 10.1002/ps.3793
       
  • Bemisia tabaci nomenclature: lessons learned
    • Authors: Laura M Boykin
      Pages: 1454 - 1459
      Abstract: BACKGROUND The nomenclature used within the whitefly research community for different putative species within Bemisia tabaci (sensu Russell) remains highly variable and confused. This was evident by the many different naming schemes researchers were using in their presentations at the 1st International Whitefly Symposium in Kolymbari, Crete, Greece (20–24 May 2013). I wanted to try to document how we, as a community, have arrived at such a state of confused nomenclature. This also included an investigation of the nomenclature used in the literature (from 2002 to 2012) by means of two online search tools (Web of Science and Scirus). RESULTS Nomenclatural data were collected at the 1st International Whitefly Symposium, based on oral presentations and posters. There were 17 different names used for the MED species and 12 different names used for the MEAM1 species of the B. tabaci species complex. Investigation of the literature revealed limited uptake of the intermediate names. CONCLUSION The intermediate names for the various species in the B. tabaci species complex – MED, MEAM1, New World, etc. – are not being used by the wider whitefly community. To move forwarrd as a community, we must work towards a formal revision of the B. tabaci complex. © 2013 Society of Chemical Industry
      PubDate: 2014-01-21T10:55:09.745024-05:
      DOI: 10.1002/ps.3709
       
  • Activity of flonicamid on the sweet potato whitely Bemisia tabaci
           (Homoptera: Aleyrodidae) and its natural enemies
    • Authors: Emmanouil Roditakis; Natasa Fytrou, Marianna Staurakaki, John Vontas, Anastasia Tsagkarakou
      Pages: 1460 - 1467
      Abstract: BACKGROUND Flonicamid is a novel systemic insecticide that acts as a feeding blocker with potential use against whiteflies within IPM control tactics. Flonicamid efficacy against Bemisia tabaci Mediterranean populations from Crete was examined, as well as side effects on selected beneficials used extensively in current IPM schemes. RESULTS Low variability in adulticide activity was detected (
      PubDate: 2014-02-19T06:24:47.244212-05:
      DOI: 10.1002/ps.3723
       
  • Bemisia tabaci females from the Mediterranean (Q) species detect and avoid
           laying eggs in the presence of pyriproxyfen, a juvenile hormone analogue
    • Authors: Pnina Moshitzky; Shai Morin
      Pages: 1468 - 1476
      Abstract: BACKGROUND Pyriproxyfen, a juvenile hormone analogue, disrupts embryogenesis, metamorphosis and adult formation in Bemisia tabaci, but does not directly affect adult females. The effect of pyriproxyfen on egg‐laying preference and performance of B. tabaci females and the influence of resistance to pyriproxyfen on these reproductive behaviours were studied. RESULTS Choice experiments utilising cotton plants treated and not treated with pyriproxyfen revealed a significant preference for egg laying on non‐treated plants both by resistant and susceptible females. No‐choice assays indicated a reduction of ∼60% in the number of eggs laid on pyriproxyfen‐treated plants by both resistant and susceptible females. The reduction in oviposition on treated plants was not accompanied with reduced expression of the vitellogenin gene or a delay in oocyte maturation, but significant accumulation of mature oocytes in the ovaries was observed, and could be reversed by transferring the females to non‐treated plants. CONCLUSION Pyriproxyfen caused reduced oviposition and enhanced mature oocyte accumulation in pyriproxyfen‐resistant and pyriproxyfen‐susceptible females. These findings can be explained by two alternative mechanisms: pyriproxyfen‐regulated physiological arrest of oviposition, involving hormonal regulation of myotrophic factors, or the hierarchy‐threshold behavioural theory of host choice, in which pyriproxyfen‐treated plants are defined as low‐quality hosts. Aspects of application are discussed. © 2013 Society of Chemical Industry
      PubDate: 2014-02-17T08:38:43.002774-05:
      DOI: 10.1002/ps.3698
       
  • Genetic structure of Bemisia tabaci Med populations from home‐range
           countries, inferred by nuclear and cytoplasmic markers: impact on the
           distribution of the insecticide resistance genes
    • Authors: Nathalie Gauthier; Cécile Clouet, Andreas Perrakis, Despoina Kapantaidaki, Michel Peterschmitt, Anastasia Tsagkarakou
      Pages: 1477 - 1491
      Abstract: BACKGROUND Insecticide resistance management in Bemisia tabaci is one of the main issues facing agricultural production today. An extensive survey was undertaken in five Mediterranean countries to examine the resistance status of Med B. tabaci species in its range of geographic origin and the relationship between population genetic structure and the distribution of resistance genes. The investigation combined molecular diagnostic tests, sequence and microsatellite polymorphism studies and monitoring of endosymbionts. RESULTS High frequencies of pyrethroid (L925I and T929V, VGSC gene) and organophosphate (F331W, ace1 gene) resistance mutations were found in France, Spain and Greece, but not in Morocco or Tunisia. Sequence analyses of the COI gene delineated two closely related mitochondrial groups (Q1 and Q2), which were found either sympatrically (Spain) or separately (France). Only Q1 was observed in Greece, Morocco and Tunisia. Bayesian analyses based on microsatellite loci revealed three geographically delineated genetic groups (France, Spain, Morocco/Greece/Tunisia) and high levels of genetic differentiation even between neighbouring samples. Evidence was also found for hybridisation and asymmetrical gene flow between Q1 and Q2. CONCLUSIONS Med B. tabaci is more diverse and structured than reported so far. On a large geographic scale, resistance is affected by population genetic structure, whereas on a local scale, agricultural practices appear to play a major role. © 2014 Society of Chemical Industry
      PubDate: 2014-03-07T08:00:05.570033-05:
      DOI: 10.1002/ps.3733
       
  • An evaluation of three predatory mite species for the control of
           greenhouse whitefly (Trialeurodes vaporariorum)
    • Authors: Nathan C Medd; Richard M GreatRex
      Pages: 1492 - 1496
      Abstract: BACKGROUND Within integrated pest control programmes, the use of high mite inoculations to control hot spots of whitefly is desirable for many growers. In this experiment, two species of predatory mites established as commercial biological control agents, Typhlodromips montdorensis and Amblyseius swirskii (Acari: Phytoseiidae), were compared with another, more recently introduced species, Amblydromalus limonicus, for their ability to control dense populations of greenhouse whitefly (Trialeurodes vaporariorum) on cucumber plants (Cucumis sativus). RESULTS Mite formulation type had a significant effect on the number of mites found on plants, but this did not correspond to increased whitefly control. Plots treated with A. limonicus or T. montdorensis, applied as loose product, had significantly reduced whitefly populations throughout the trial. Analysis showed that no species was observed more often on leaves with higher whitefly densities than on those with lower densities. CONCLUSION No species was clearly identified as a suitable candidate for treatment of high‐density whitefly colonies, but results suggest the highest level of predation in A. limonicus. Strategies for the effective use of these predatory mite species in control programmes are discussed. © 2014 Society of Chemical Industry
      PubDate: 2014-05-08T07:56:56.386116-05:
      DOI: 10.1002/ps.3794
       
  • Nuclear and cytoplasmic differentiation among Mediterranean populations of
           Bemisia tabaci: testing the biological relevance of cytotypes
    • Authors: Gabriel Terraz; Gwenaelle Gueguen, Judit Arnó, Frédéric Fleury, Laurence Mouton
      Pages: 1503 - 1513
      Abstract: BACKGROUND The taxonomy of the species complex Bemisia tabaci is still an unresolved issue. Recently, phylogenetic analysis based on mtCOI identified 31 cryptic species. However, mitochondrial diversity is observed within these species, associated with distinct symbiotic bacterial communities forming associations, which here are called cytotypes. The authors investigated the biological significance of two cytotypes (Q1 and Q2) belonging to the Mediterranean species, which have only been found in allopatry in the Western Mediterranean to date. Sampling was done over a few years in Western Europe, and sympatric situations were found that allowed their reproductive compatibility to be tested in the field with the use of microsatellites. RESULTS The field survey indicated that, in spite of its recent introduction, Q2 is well established in France and Spain, where it coexists with Q1. Microsatellite data showed that, in allopatry, Q1 and Q2 are highly differentiated, while there is little or no genetic differentiation when they coexist in sympatry, suggesting a high rate of hybridisation. Crossing experiments in the lab confirmed their interfertility. CONCLUSION Q1 and Q2 hybridise, which confirms that they belong to the same species, in spite of the high degree of genetic differentiation at both the cytoplasmic and nuclear levels, and also suggests that their symbiotic bacteria do not prevent hybridisation. © 2014 Society of Chemical Industry
      PubDate: 2014-05-12T07:49:59.511685-05:
      DOI: 10.1002/ps.3792
       
  • Variation in mortality among populations is higher for pymetrozine than
           for imidacloprid and spiromesifen in Trialeurodes vaporariorum in
           greenhouses in Finland
    • Authors: Irina Ovčarenko; Leena Lindström, Kari Saikkonen, Irene Vänninen
      Pages: 1524 - 1530
      Abstract: BACKGROUND Insecticide resistance in Trialeurodes vaporariorum W. is unknown in the species' northern distribution range where it inhabits mainly commercial greenhouses. Resistance development in whiteflies feeding on year‐round crops in greenhouses is possible owing to the use of chemical treatments to back up biocontrol. The authors tested the response levels to spiromesifen, pymetrozine and imidacloprid in whiteflies collected from seven greenhouses within a 35 km radius in western Finland. RESULTS All except one (PR) population had LC50 values below the recommended concentrations for the tested compounds. However, some populations showed reduced susceptibility to pymetrozine in comparison with the reference susceptible population. Resistance ratios to pymetrozine were highly variable (resistance ratio 0.5–39.7), even among closely located greenhouses, and higher than those for imidacloprid (resistance ratio 1.05–10.5) and spiromesifen (resistance ratio 0.8–11.5). LC50 values and application frequencies of pymetrozine correlated positively among the sampled populations. CONCLUSION High variation in resistance levels to pymetrozine among populations within natural whitefly dispersal limits reflects variation in the usage of this compound among individual greenhouse crop producers. Thus, resistance management is recommended at the individual greenhouse crop producer level, even in a dense production cluster. © 2014 Society of Chemical Industry
      PubDate: 2014-03-28T06:58:36.533071-05:
      DOI: 10.1002/ps.3766
       
  • Host suitability comparison between the MEAM1 and AsiaII 1 cryptic species
           of Bemisia tabaci in cotton‐growing zones of Pakistan
    • Authors: Muhammad Z Ahmed; Muhammad Naveed, Muhammad Noor ul Ane, Shun‐Xiang Ren, Paul De Barro, Bao‐Li Qiu
      Pages: 1531 - 1537
      Abstract: BACKGROUND Bemisia tabaci is a cryptic species complex. In Pakistan, members of the complex, MEAM1 and AsiaII 1, are the predominant species infesting cotton. The biology of the two on cotton, collard, cucumber and tomato was studied. RESULTS In all cases there were significant interactions between species and host. MEAM1 developmental periods did not differ significantly across hosts, whereas AsiaII 1 developed more slowly on vegetables than on cotton. MEAM1 survival was highest on tomato (53.5 ± 1.1%), while AsiaII 1 survived best on cotton (67.3 ± 11.6%). MEAM1 longevity and fecundity were highest on tomato (14.7 ± 1.7 days and 82.4 ± 9.9 eggs), while AsiaII 1 longevity and fecundity were highest on cotton (23.7 ± 2.5 days and 135.2 ± 13.6 eggs). The MEAM1 intrinsic rates of increase (rm) on cotton and vegetable were similar (0.08–0.10), whereas the AsiaII 1 rm on cotton (0.15) was higher than on vegetables (0.11–0.13). The biology of MEAM1 from Pakistan was compared with published studies; it had a consistently slower rate of development, lower percentage survival, lower adult longevity, longer generation time, lower net reproductive rate and lower rm. CONCLUSIONS MEAM1 performed similarly across all hosts, whereas AsiaII 1 performed better on cotton. The comparison between the Pakistani MEAM1 with published studies suggests that the invasive MEAM1 may have higher performance. © 2013 Society of Chemical Industry
      PubDate: 2014-02-17T08:40:40.253656-05:
      DOI: 10.1002/ps.3716
       
  • Comparative susceptibility of Bemisia tabaci to imidacloprid in
           field‐ and laboratory‐based bioassays
    • Authors: Steven J Castle; Paul Merten, Nilima Prabhaker
      Pages: 1538 - 1546
      Abstract: BACKGROUND Bemisia tabaci biotype B is a resistance‐prone pest of protected and open agriculture. Systemic uptake bioassays used in resistance monitoring programs have provided important information on susceptibility to neonicotinoid insecticides, but have remained decoupled from field performance. Simultaneous bioassays conducted in field and laboratory settings were compared and related to concentrations of imidacloprid in plant tissue for clearer interpretation of resistance monitoring data. RESULTS Mean mortalities of adult whiteflies confined on cantaloupe leaves field‐treated with three rates of imidacloprid did not exceed 40% in two trials. In contrast, laboratory bioassays conducted on different subsets of the same whitefly populations yielded concentration–response curves suggestive of susceptibility to imidacloprid in five populations (LC50 values from 1.02 to 6.4) relative to a sixth population (LC50 = 13.8). In the field, densities of eggs and nymphs were significantly lower on the imidacloprid‐treated cantaloupes compared with the untreated control, but the margin of control was greater in 2006 than in 2007. The potential impact of imidacloprid on whitefly eggs was explored in a greenhouse test that showed egg mortality occurring in both early (one‐day‐old) and late (three‐day‐old) eggs on cotton leaves systemically treated with imidacloprid. Quantification of imidacloprid residues in cotton leaves used routinely in systemic uptake bioassays revealed concentrations that greatly exceeded concentrations found in the field‐treated cantaloupe leaves, at least at the three highest solution concentrations used for uptake. CONCLUSION Systemic uptake bioassays have been widely used for monitoring B. tabaci resistance to imidacloprid, but without knowledge of imidacloprid concentrations that occur in test leaves relative to field concentrations. Higher mortality observed in systemic uptake bioassays relative to field‐treated cantaloupes in this study suggests that field rates of imidacloprid are only partially effective against B. tabaci adults, in contrast to systemic uptake bioassays that showed susceptibility to imidacloprid. The discrepancy between field‐ and laboratory‐based mortalities is probably due to extraordinarily high concentrations of imidacloprid that can occur in leaves of systemic uptake bioassays, potentially skewing perception of susceptibility to imidacloprid. Published 2013. This article is a U.S. Government work and is in the public domain in the USA
      PubDate: 2014-02-03T21:23:12.383365-05:
      DOI: 10.1002/ps.3717
       
  • Transmission specificities of plant viruses with the newly identified
           species of the Bemisia tabaci species complex
    • Authors: Jane E Polston; Paul De Barro, Laura M Boykin
      Pages: 1547 - 1552
      Abstract: Bemisia tabaci has had a colorful nomenclatural past and is now recognized as a species complex. This new species framework has added many new areas of research including adding new insight into the virus transmission specificity of the species in the B. tabaci species complex. There is a wide disparity in what is known about the transmission of plant viruses by different members of the B. tabaci species complex. In this paper, we have synthesized the transmission specificities of the plant viruses transmitted by species belonging to the complex. There are five genera of plant viruses with members that are transmitted by species of the B. tabaci species complex. The transmission of viruses belonging to two of these, Begomovirus and Crinivirus, are well studied and much is known in regards to the relationship between species and transmission and etiology. This is in contrast to viruses of the genera, Torradovirus and Carlavirus, for which very little is known inregards to their transmission. This is the first attempt to integrate viral data within the new B. tabaci species complex framework. It is clear that matching historical transmission data with the current species framework is difficult due to the lack of awareness of the underlying genetic diversity within B. tabaci. We encourage all researchers to determine which species of B. tabaci they are using to facilitate association of phenotypic traits with particular members of the complex. © 2014 Society of Chemical Industry
      PubDate: 2014-03-03T08:18:36.802883-05:
      DOI: 10.1002/ps.3738
       
  • Ipomovirus – an atypical genus in the family Potyviridae
           transmitted by whiteflies
    • Authors: Aviv Dombrovsky; Victoria Reingold, Yehezkel Antignus
      Pages: 1553 - 1567
      Abstract: Ipomoviruses (genus Ipomovirus) are whitefly‐transmitted viruses assigned to the family Potyviridae. They are characterised by filamentous flexible particles and a positive‐sense single‐stranded RNA (+ssRNA) genome. The viral genome is translated into a polyprotein precursor, which is processed into mature proteins and a short overlapping open reading frame. The genus Ipomovirus contains four accepted species and one unapproved species, and two other tentative members have recently been characterised. Ipomoviruses cause serious economic losses in many important crops, including cassava, sweet potato, cucurbits, tomato and aubergine. These viruses are transmitted by whiteflies in a non‐circulative, semi‐persistent manner, the virions being retained on the external surface of the vectors' mouthparts for a few days or weeks. Comparison of the available complete genome sequences of different ipomoviruses revealed differences in their genome organisation and a considerable variation in their proteins and conserved motifs that may reflect functional differences. This review summarises the current knowledge of the members within the genus Ipomovirus, focusing on genome organisation, taxonomic classification and the mechanism by which they are transmitted. © 2014 Society of Chemical Industry
      PubDate: 2014-03-03T08:31:13.310675-05:
      DOI: 10.1002/ps.3735
       
  • Dynamics of biotypes B and Q of the whitefly Bemisia tabaci and its impact
           on insecticide resistance
    • Authors: Abraham Rami Horowitz; Isaac Ishaaya
      Pages: 1568 - 1572
      Abstract: BACKGROUND The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a key pest in many agricultural crops, including vegetables, ornamentals and field crops. B. tabaci is known for its genetic diversity, which is expressed in a complex of biotypes or, as recently suggested, a complex of distinct cryptic species. The biotypes are largely differentiated on the basis of biochemical or molecular polymorphism and differ in characteristics such as host plant range, attraction by natural enemies, secondary symbionts and expression of insecticide resistance. An extensive survey of B. tabaci biotypes and their impact on insecticide resistance was conducted from 2003 to 2012 in cotton fields and other crops from several locations in Israel. RESULTS Two biotypes of B. tabaci, B and Q, were identified, and some differences in the biotype dynamics were recorded from different areas. In northern Israel from 2003 to 2007, a higher proportion of the B biotype was consistently found in early season. However, by the end of the season a definite rise of the Q biotype was sampled, ranging from 60 to 100%, along with high resistance to the insect growth regulator (IGR) pyriproxyfen and to a lesser extent to the neonicotinoid insecticides. In fields located in the central part of Israel, the Q biotype was predominant throughout the seasons, with high resistance to pyriproxyfen. Since 2009, a significant shift in the biotype ratios has been observed: the B biotype has come to predominate over the Q biotype ranging up to 90% or more in most fields. At the same time, resistance to the IGR pyriproxyfen was reduced considerably. CONCLUSION The possible reasons for the change in the dynamics of B. tabaci biotypes, and its implications for resistance management, are discussed. Strong B. tabaci resistance to pyriproxyfen in Israel has been associated with the Q rather than with the B biotype. The B biotype is more competitive than the Q biotype under untreated conditions. Reduction in the acreage of cotton fields during recent years, along with a decrease in insecticide use, especially pyriproxyfen, has resulted in the expansion of the B biotype. © 2014 Society of Chemical Industry
      PubDate: 2014-03-19T08:12:46.166772-05:
      DOI: 10.1002/ps.3752
       
  • Chemical class rotations for control of Bemisia tabaci (Hemiptera:
           Aleyrodidae) on poinsettia and their effect on cryptic species population
           composition
    • Authors: Cindy L McKenzie; Vivek Kumar, Cristi L Palmer, Ronald D Oetting, Lance S Osborne
      Pages: 1573 - 1587
      Abstract: BACKGROUND Bemisia tabaci, a polyphagous insect with over 900 host plants, is an effective vector of more than 100 plant viruses. Being highly fecund, B. tabaci has the potential to develop insecticide resistance rapidly, as demonstrated by reports of use failures with MEAM1 and MED cryptic species (commonly known as biotypes B and Q respectively). Insecticide resistance management is a key component of pest management practices. The research herein studied season‐long rotational management programs on poinsettia and their impact on the ratio of MEAM1:MED cryptic species in the surviving treated populations. RESULTS In all four experiments, only three of the treatments completely eliminated the adult or immature whiteflies, but all significantly reduced the populations. Out of 18 active ingredients tested, dinotefuran (applied as a soil drench) was the most efficacious against both MEAM1 and MED cryptic species compared with the other chemical or biorational insecticides evaluated. Reduced susceptibility of MED was reported against a variety of treatment regimes. CONCLUSION Rotations can be used to manage MEAM1 and MED cryptic species and maintain a very low population level or completely eliminate Bemisia on poinsettia. It is imperative to continue to emphasize the importance of rotating among different modes of action in pest management programs in order to retain effective chemistries for as long as possible in the market place. © 2014 Society of Chemical Industry
      PubDate: 2014-03-03T08:34:13.788927-05:
      DOI: 10.1002/ps.3736
       
  • Detoxification enzymes of Bemisia tabaci B and Q: biochemical
           characteristics and gene expression profiles
    • Authors: Litao Guo; Wen Xie, Shaoli Wang, Qingjun Wu, Rumei Li, Nina Yang, Xin Yang, Huipeng Pan, Youjun Zhang
      Pages: 1588 - 1594
      Abstract: BACKGROUND The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most invasive and destructive pests of field crops worldwide. The sibling species B and Q are the two most damaging members of the B. tabaci species complex. That Q is more resistant than B to many insecticides has been well documented. Over the last decade, Q has gradually displaced B and has become the dominant form of B. tabaci in field agricultural systems in most parts of China. To help understand the differences in insecticide resistance, the activities and gene expression profiles of detoxification enzymes in B. tabaci B and Q were investigated. RESULTS The activity of P450 towards 7‐ethoxycoumarin was significantly higher (1.46‐fold higher) in Q than in B. The expression of 43 of 65 P450 genes was higher (>1‐fold) in Q than in B, and expression for eight P450 genes was more than 50‐fold greater in Q than in B. The increased expression of selected P450 genes in Q relative to B was confirmed with two other B strains and two other Q strains. On the other hand, carboxylesterase (CarE) activity was significantly lower (0.71‐fold lower) in Q than in B; the Km value of CarE was significantly lower in B than in Q, but the opposite was true for the Vmax value of CarE. Glutathione S‐transferase activity and values of Km and Vmax did not differ between B and Q. CONCLUSION Enhanced metabolic detoxification of insecticides by P450s may be an important reason why B. tabaci Q is more resistant than B. tabaci B to insecticides. © 2014 Society of Chemical Industry
      PubDate: 2014-04-08T03:03:14.872439-05:
      DOI: 10.1002/ps.3751
       
  • Adaptation to nicotine in the facultative tobacco‐feeding hemipteran
           Bemisia tabaci
    • Authors: Adi Kliot; Svetlana Kontsedalov, John S Ramsey, Georg Jander, Murad Ghanim
      Pages: 1595 - 1603
      Abstract: BACKGROUND Plant defensive metabolites such as nicotine can provide barriers to host‐range expansion by generalist herbivores. Nicotine is one of the most abundant and toxic plant secondary metabolites in nature and is defined by high toxicity to plant‐feeding insects. There is significant variation in nicotine tolerance among Bemisia tabaci (tobacco whitefly) isolates. Some nicotine‐tolerant B. tabaci strains can consume 40‐fold higher nicotine levels than susceptible strains, and also show cross‐resistance to neonicotinoid insecticides. In this study, biological and molecular assays were used to investigate the responses of B. tabaci strains that differ in their ability to tolerate dietary nicotine. RESULTS Egg laying and honeydew secretion bioassays as well as gene expression microarrays were used to measure B. tabaci biological parameters and gene transcripts misregulated in response to nicotine in resistant and susceptible strains. The resistant B. tabaci strain laid significantly fewer eggs and excreted more honeydew on a tobacco strain with high levels of nicotine, suggesting a fitness cost effect. The molecular response was drastic in the susceptible strain, while the resistant strain exhibited moderate response. Higher expression of the previously identified CYP6CM1 P450 monooxygenase gene related to the resistance to neonicotinoids, as well as other P450s and metabolic genes, was identified in the resistant and susceptible strains after exposure to nicotine. CONCLUSIONS Nicotine is a very toxic plant natural compound, and its mode of action resembles that of synthetic neonicotinoids. The biological and molecular responses observed in this study suggest that nicotine may play an important role in providing barriers for host‐plant expansion by generalists, and may act as a natural factor that contributes to the development of insect populations resistant to synthetic pesticides. © 2014 Society of Chemical Industry
      PubDate: 2014-03-06T10:37:46.177434-05:
      DOI: 10.1002/ps.3739
       
  • Efficiency of plant induced volatiles in attracting Encarsia formosa and
           Serangium japonicum, two dominant natural enemies of whitefly Bemisia
           tabaci in China
    • Authors: Shao‐Jian Li; Su‐Li Ren, Xia Xue, Shun‐Xiang Ren, Andrew GS Cuthbertson, Nicole M van Dam, Bao‐Li Qiu
      Pages: 1604 - 1610
      Abstract: BACKGROUND Whitefly Bemisia tabaci is a globally distributed and most destructive pest to agriculture. Owing to increasing chemical resistance, a long‐lasting strategy to manage this pest must involve biological control. Herbivore‐induced plant volatiles (HIPVs) usually play a profoundly important role in the foraging behaviour of natural enemies. Here, the effects of HIPVs from Chinese broccoli on the foraging behaviour of two dominant natural enemy species of B. tabaci in China, Encarsia formosa and Serangium japonicum, were investigated using a four‐arm olfactometer, and exogenous jasmonic acid (JA) was used to induce plant volatiles to mimic the damage of the herbivore pest. RESULTS The parasitoid E. formosa was found to be more attracted by the volatiles from JA‐induced broccoli than those from control plants. The residence times of E. formosa in the final‐choice areas closed to volatiles from shoot JA (SJA)‐ and root JA (RJA)‐induced plants were 119.8 ± 35.2 s and 99.8 ± 34.7 s respectively in the dual‐choice experiments, and 123.8 ± 32.0 s and 102.3 ± 28.7 s respectively in the three‐choice experiment. All are significantly longer than those spent in the final‐choice area closed to volatiles from control plants (CON). JA‐induced volatiles were also only a little more attractive to the predator S. japonicum. However, there was no significant difference between each of the two natural enemies in residence time spent in the final‐choice areas closed to SJA, RJA or CON volatiles in both the dual‐ and three‐choice experiments. Furthermore, the number of times that the parasitoid or predator entered the SJA, RJA and CON final‐choice areas was not significantly different in any of the experiments. CONCLUSION The present results indicate that RJA‐ and SJA‐induced plant volatiles have higher efficiencies in attracting the natural enemies of whitefly B. tabaci. The attractive efficiencies varied according to the plant volatiles that JA induced, and also depended on the natural enemy species. The parasitoid E. formosa seems to be more sensitive to and attracted by the induced volatiles than the predator S. japonicum. © 2014 Society of Chemical Industry
      PubDate: 2014-03-19T08:12:22.572779-05:
      DOI: 10.1002/ps.3749
       
  • Modelling the potential distribution of Bemisia tabaci in Europe in light
           of the climate change scenario
    • Authors: Gianni Gilioli; Sara Pasquali, Simone Parisi, Stephan Winter
      Pages: 1611 - 1623
      Abstract: BACKGROUND Bemisia tabaci is a serious pest of agricultural and horticultural crops in greenhouses and fields around the world. This paper deals with the distribution of the pest under field conditions. In Europe, the insect is currently found in coastal regions of Mediterranean countries where it is subject to quarantine regulations. To assess the risk presented by B. tabaci to Europe, the area of potential establishment of this insect, in light of the climate change scenario, was assessed by a temperature‐dependent physiologically based demographic model (PBDM). RESULTS The simulated potential distribution under current climate conditions has been successfully validated with the available field records of B. tabaci in Europe. Considering climate change scenarios of +1 and +2 °C, range expansion by B. tabaci is predicted, particularly in Spain, France, Italy, Greece and along the Adriatic coast of the Balkans. Nonetheless, even under the scenario of +2 °C, northern European countries are not likely to be at risk of B. tabaci establishment because of climatic limitations. CONCLUSION Model validation with field observations and evaluation of uncertainties associated with model parameter variability support the reliability of model results. The PBDM developed here can be applied to other organisms and offers significant advantages for assessing the potential distribution of invasive species. © 2014 Society of Chemical Industry
      PubDate: 2014-02-26T11:18:46.586055-05:
      DOI: 10.1002/ps.3734
       
  • Expression and functional characterisation of a soluble form of Tomato
           yellow leaf curl virus coat protein
    • Authors: Lan‐Lan Wang; Xue‐Mei Wei, Xiao‐Dong Ye, Hong‐Xing Xu, Xue‐Ping Zhou, Shu‐Sheng Liu, Xiao‐Wei Wang
      Pages: 1624 - 1631
      Abstract: BACKGROUND Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus within the family Geminiviridae, is an important pathogen of tomato in many tropical, subtropical and temperate regions. TYLCV is exclusively transmitted by the whitefly Bemisia tabaci in a circulative manner. The viral coat protein (CP) has been assumed to play important roles in the entry of TYLCV into the insect midgut cells. RESULTS Testing the hypothesis that CP plays an important role in TYLCV acquisition by B. tabaci, a soluble form of the CP was expressed and purified. The purified recombinant CP made it possible to examine the function of TYLCV CP without other viral proteins. In an in vivo binding assay, specific binding of TYLCV CP to B. tabaci midguts was detected when purified CP was fed to B. tabaci. In addition, real‐time polymerase chain reaction analysis of virus titre revealed that B. tabaci fed with purified CP had reduced the level of virus in their midgut compared with those fed with bovine serum albumin or maltose‐binding protein. These results suggest that binding of TYLCV CP to the B. tabaci midgut specifically inhibits virus acquisition. CONCLUSIONS The findings that TYLCV CP binds to B. tabaci midguts and decreases virus acquisition provide direct evidence that CP mediates the attachment of TYLCV to receptors on the epithelial cells of the B. tabaci midgut. © 2014 Society of Chemical Industry
      PubDate: 2014-03-17T06:16:18.225518-05:
      DOI: 10.1002/ps.3750
       
  • Degradation mechanisms of the Tomato yellow leaf curl virus coat protein
           following inoculation of tomato plants by the whitefly Bemisia tabaci
    • Authors: Rena Gorovits; Adi Moshe, Murad Ghanim, Henryk Czosnek
      Pages: 1632 - 1639
      Abstract: BACKGROUND Tomato yellow leaf curl virus (TYLCV) is a begomovirus infecting tomato cultures worldwide. TYLCV is transmitted to plants by the whitefly Bemisia tabaci. Once in the plant, the virus is subjected to attack by the host‐plant defences, which may include sequestration in aggregates, proteolysis, ubiquitination, 26S proteasome degradation and autophagy. Elucidating how the virus avoids destruction will make it possible to understand infection and possibly devise countermeasures. RESULTS The accumulation of viral coat protein (CP) and of viral DNA in plants is a marker of a successful virus transmission by B. tabaci. In response to infection, tomato tissues display multiple ways of degrading TYLCV proteins and DNA. In this study it is shown that CP (in soluble and insoluble states) is the target of protease digestion, 26S proteasome degradation and autophagy. The highest degradation capacity was detected among soluble proteins and proteins in large aggregates/inclusion bodies; cytoplasmic extracts displayed higher activity than nuclear fractions. The very same fractions possessed the highest capacity to degrade viral genomic DNA. Separately, 26S proteasome degradation was associated with large aggregates (more pronounced in the nuclear than in the cytoplasmic fractions), which are indicators of a successful abduction of plants by viruses. Autophagy/lysosome/vacuole degradation was a characteristic of intermediate aggregates, sequestering the CP in the cytoplasm and retarding the development of large aggregates. Chloroplast proteases were active in soluble as well as in insoluble protein extracts. CONCLUSIONS To the best of the authors' knowledge, this study is the first attempt to identify elements of the virus‐targeted degradation machinery, which is a part of the plant response to virus invasion. © 2014 Society of Chemical Industry
      PubDate: 2014-03-04T11:25:43.008147-05:
      DOI: 10.1002/ps.3737
       
  • Invasion of the Q2 mitochondrial variant of Mediterranean Bemisia tabaci
           in southern Italy: possible role of bacterial endosymbionts
    • Authors: Giuseppe Parrella; Anna Giulia Nappo, Elena Manco, Barbara Greco, Massimo Giorgini
      Pages: 1514 - 1523
      Abstract: BACKGROUND The whitefly Bemisia tabaci (Gennadius) is a complex of cryptic species, some of which, namely the Mediterranean (MED) and the Middle East–Asia Minor 1 (MEAM1), are highly invasive and injurious crop pests worldwide and able to displace local genotypes. Invasiveness of B. tabaci may depend on the phenotype of inherited bacterial endosymbionts. Here, the B. tabaci genetic diversity variation that has occurred in recent years in southern Italy was examined. Whitefly was genotyped by restriction fragment length polymorphism analysis of polymerase‐chain‐reaction‐amplified fragments (PCR‐RFLP) of the COI gene and molecular identification of endosymbionts. Possible factors leading to the observed genetic diversity were examined. RESULTS Q1 and Q2 mitochondrial types of MED, the only species found, coexisted in the field, while MEAM1 disappeared. A large spreading of Q2 (70% of individuals) was observed for the first time in Italy. Q2 showed a significant female‐biased sex ratio and largely outnumbered Q1 on solanaceous hosts, in greenhouses and on insecticide‐treated plants. Q1, with an even sex ratio, slightly prevailed on non‐solanaceous hosts, especially on wild and untreated plants. Endosymbiont composition was associated with the mitochondrial type. Hamiltonella and Rickettsia were found at near fixation in Q1 and Q2 respectively; Arsenophonus, Cardinium and Wolbachia were found in both types, although at different frequencies. CONCLUSIONS Q2 invasion seems to have been favoured by the agroecological conditions of southern Italy and by the female‐biased sex ratio. Endosymbionts may have a role in Q2 invasiveness, acting as sex‐ratio manipulators (e.g. Rickettsia) and possibly by benefiting the host fitness. © 2013 Society of Chemical Industry
      PubDate: 2013-12-17T10:45:25.734003-05:
      DOI: 10.1002/ps.3686
       
 
 
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