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  Subjects -> ENGINEERING (Total: 2160 journals)
    - CHEMICAL ENGINEERING (186 journals)
    - CIVIL ENGINEERING (168 journals)
    - ELECTRICAL ENGINEERING (93 journals)
    - ENGINEERING (1165 journals)
    - ENGINEERING MECHANICS AND MATERIALS (355 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (57 journals)
    - MECHANICAL ENGINEERING (81 journals)

ENGINEERING (1165 journals)            First | 4 5 6 7 8 9 10 11 | Last

Journal of Inequalities and Applications     Open Access  
Journal of Infrared, Millimeter and Terahertz Waves     Hybrid Journal   (Followers: 1)
Journal of Inverse and Ill-posed Problems     Hybrid Journal   (Followers: 1)
Journal of Irrigation and Drainage Engineering     Full-text available via subscription   (Followers: 15)
Journal of K-Theory     Full-text available via subscription   (Followers: 1)
Journal of King Saud University - Engineering Sciences     Open Access  
Journal of Konbin     Open Access  
Journal of Liquid Chromatography & Related Technologies     Hybrid Journal   (Followers: 9)
Journal of Management in Engineering     Full-text available via subscription   (Followers: 10)
Journal of Manufacturing Science and Engineering     Full-text available via subscription   (Followers: 11)
Journal of Manufacturing Systems     Full-text available via subscription   (Followers: 6)
Journal of Manufacturing Technology Management     Hybrid Journal   (Followers: 4)
Journal of Mathematical Modelling and Algorithms     Hybrid Journal   (Followers: 2)
Journal of Mechatronics     Full-text available via subscription  
Journal of Membrane and Separation Technology     Hybrid Journal  
Journal of Metallurgy     Open Access   (Followers: 3)
Journal of Middle European Construction and Design of Cars     Open Access   (Followers: 1)
Journal of Molecular Catalysis B: Enzymatic     Hybrid Journal   (Followers: 1)
Journal of Motor Behavior     Hybrid Journal   (Followers: 9)
Journal of Multivariate Analysis     Hybrid Journal   (Followers: 6)
Journal of Nanoengineering and Nanomanufacturing     Full-text available via subscription   (Followers: 1)
Journal of Nanoparticle Research     Hybrid Journal   (Followers: 2)
Journal of Nanoscience     Open Access  
Journal of Nanoscience and Nanotechnology     Full-text available via subscription   (Followers: 11)
Journal of NanoScience, NanoEngineering & Applications     Full-text available via subscription  
Journal of Nanotechnology     Open Access   (Followers: 3)
Journal of Nanotechnology in Engineering and Medicine     Full-text available via subscription   (Followers: 6)
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 Nuclear Engineering & Technology     Full-text available via subscription  
Journal of Ocean Engineering and Marine Energy     Hybrid Journal  
Journal of Oceanography and Marine Science     Open Access   (Followers: 2)
Journal of Operations Management     Hybrid Journal   (Followers: 19)
Journal of Optics     Hybrid Journal   (Followers: 2)
Journal of Optimization     Open Access  
Journal of Optoelectronics Engineering     Open Access  
Journal of Organizational Behavior     Hybrid Journal   (Followers: 32)
Journal of Petroleum Science Research     Open Access  
Journal of Phase Equilibria and Diffusion     Hybrid Journal   (Followers: 5)
Journal of Power Sources     Partially Free   (Followers: 31)
Journal of Pre-College Engineering Education Research     Open Access  
Journal of Pressure Vessel Technology     Full-text available via subscription   (Followers: 11)
Journal of Professional Issues in Engineering Education and Practice     Full-text available via subscription   (Followers: 6)
Journal of Quality and Reliability Engineering     Open Access   (Followers: 1)
Journal of Quality in Maintenance Engineering     Hybrid Journal   (Followers: 4)
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: 5)
Journal of Regional Science     Hybrid Journal   (Followers: 10)
Journal of Reinforced Plastics and Composites     Hybrid Journal   (Followers: 27)
Journal of Research of NIST     Open Access   (Followers: 1)
Journal of Research Updates in Polymer Science     Hybrid Journal  
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: 5)
Journal of Safety Research     Hybrid Journal   (Followers: 19)
Journal of Science and Technology     Open Access  
Journal of Science and Technology (Ghana)     Open Access   (Followers: 2)
Journal of Science and Technology Policy Management     Hybrid Journal   (Followers: 2)
Journal of Scientific Computing     Hybrid Journal   (Followers: 3)
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: 3)
Journal of Shanghai Jiaotong University (Science)     Hybrid Journal  
Journal of Sol-Gel Science and Technology     Hybrid Journal   (Followers: 1)
Journal of Solar Energy     Open Access   (Followers: 5)
Journal of Solar Energy Engineering     Full-text available via subscription   (Followers: 16)
Journal of Superconductivity and Novel Magnetism     Partially Free   (Followers: 1)
Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques     Hybrid Journal   (Followers: 2)
Journal of Surveying Engineering     Full-text available via subscription   (Followers: 7)
Journal of Technology Management & Innovation     Open Access   (Followers: 3)
Journal of Testing and Evaluation     Full-text available via subscription   (Followers: 16)
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  
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   (Followers: 1)
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: 3)
Journal of Thermal Stresses     Hybrid Journal   (Followers: 3)
Journal of Transplantation     Open Access   (Followers: 4)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 6)
Journal of Transportation Engineering     Full-text available via subscription   (Followers: 14)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 14)
Journal of Tribology     Full-text available via subscription   (Followers: 27)
Journal of Turbomachinery     Full-text available via subscription   (Followers: 9)
Journal of Turbulence     Hybrid Journal   (Followers: 1)
Journal of Unmanned Vehicle Systems     Full-text available via subscription   (Followers: 2)
Journal of Urban and Environmental Engineering     Open Access  
Journal of Urban Planning and Development     Full-text available via subscription   (Followers: 32)
Journal of Urban Regeneration & Renewal     Full-text available via subscription   (Followers: 17)
Journal of Vibration and Acoustics     Full-text available via subscription   (Followers: 28)
Journal of Visualization     Hybrid Journal   (Followers: 2)

  First | 4 5 6 7 8 9 10 11 | Last

Journal Cover   Pest Management Science
  [SJR: 1.262]   [H-I: 72]   [5 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  [1610 journals]
  • Intraguild interactions among specialized pollen‐feeders and
           generalist phytoseiids and their effect on citrus rust mite suppression
    • Authors: Yonatan Maoz; Shira Gal, Yael Argov, Sylvie Domeratzky, Moshe Coll, Eric Palevsky
      Abstract: Background Antagonistic interactions among predators with shared prey are thought to hamper their ability to suppress herbivores. Our aim was to quantify intraguild interactions in omnivorous predatory mite assemblages in the presence of pollen, and assess their effect on pest populations. We focused on the following naturally occurring phytoseiid species in Israeli citrus orchards and their ability to suppress a key pest, the citrus rust mite (CRM) Phyllocoptruta oleivora (Eriophyidae): the generalists Amblyseius swirskii and Typhlodromus athiasae and the specialized pollen feeders Iphiseius degenerans, Euseius scutalis, E. stipulatus and E. victoriensis. Evaluations were performed on two spatial scales, tree seedlings and leaf discs. Results On seedlings, experiments were conducted to quantify the interactions between predators in the presence of pollen and its effects on CRM suppression. On leaf discs intraguild interactions were studied between pairs of phytoseiid species in the presence of pollen without CRM. On seedlings, the specialized pollen predators were more effective at suppressing CRM populations than the generalist predators. Conclusion In most cases, the more aggressive intraguild predator was the specialized pollen feeder. Similarly, leaf disc experiments suggest that in these interactions, the specialized pollen‐feeders tend to be the intraguild predators more often than the intraguild prey.
      PubDate: 2015-07-01T02:26:03.251599-05:
      DOI: 10.1002/ps.4073
       
  • Cross‐resistance and baseline susceptibility of Spodoptera litura
           (Fabricius) (Lepidoptera: Noctuidae) to cyantraniliprole in the south of
           China
    • Authors: Song Sang; Benshui Shu, Xin Yi, Jie Liu, Meiying Hu, Guohua Zhong
      Abstract: BACKGROUND The Oriental leafworm moth, Spodoptera litura Fab. (Lepidoptera: Noctuidae), is a widely distributed polyphagous insect pest in Asia, which has been shown to be resistant to various types of insecticides. The newly registered anthranilic diamide cyantraniliprole provided novel insight and great opportunities to control S.litura. RESULTS In this study, the susceptibilities of S. litura collected from South China to cyantraniliprole were measured by standard leaf disc, obvious variation of susceptibility was observed among the 17 field populations with LC50 values varying from 0.206 to 1.336 mg(AI)/L. Significant correlations were detected between the LC50 values of cyantraniliprole and chlorantraniliprole (p0.05) was observed between the two anthranilic diamides and other insecticides with different action mechanisms (delcamethrin, chlorpyrifos, indoxacarb and emamectin benzoate). Piperonyl butoxide showed obvious synergism in Lab‐Sus, ZC14 and cyantraniliprole‐resistant strains, diethyl maleate and S,S,S‐tributylphorotrithioate had no obvious synergistic effects in all tested strains. CONCLUSION These results revealed obvious region variation in cyantraniliprole susceptibilities among populations of S. liture from different areas, and the potential cross‐resistance to chlorantraniliprole, which suggested the S.litura could develop resistance to cyantraniliprole. The detoxification enzymes might not involve in the observed tolerance in field collected populations and the cyantraniliprole‐resistance strain.
      PubDate: 2015-06-29T00:29:36.196403-05:
      DOI: 10.1002/ps.4068
       
  • Monitoring techniques of the western corn rootworm are the precursor to
           effective IPM strategies
    • Authors: D. Lemic; K. M. Mikac, A. Kozina, H. A. Benitez, C. M. McLean, R. Bažok
      Abstract: BACKGROUND The western corn rootworm (WCR) is economically the most important pest of maize in Croatia. To predict WCR adult population abundance and variability, traditional, genetic and morphometric monitoring of populations was conducted over time through each phase of the WCR invasion process in Croatia. RESULTS Through traditional monitoring it was shown that WCR established their current population and reached economic densities after 14 years persisting in the study area. Regression tree based modelling showed that the best predictor of WCR adult abundance was the total amount of rainfall. Genetic monitoring indicated that genetic differentiation increased over time at the intra‐population level and morphometric monitoring indicated that wing morphotypes varied according to edaphic landscape changes. CONCLUSION Traditional population metric surveys are important in WCR integrated pest management (IPM) as such surveys can be effectively used to predict population abundances. Novel‐use monitoring techniques such as genetics and geometric morphometrics can be used to provide valuable information on variation within and among populations. The monitoring techniques presented herein provide sound data to assist in the understanding of both WCR ecology and population genetics and as such may provide more information than what is currently available using traditional techniques (e.g. sticky traps) and as such these additional techniques should be written into IPM for WCR.
      PubDate: 2015-06-26T02:51:36.270136-05:
      DOI: 10.1002/ps.4072
       
  • Molecular analysis of cyenopyrafen resistance in the two‐spotted
           spider mite Tetranychus urticae
    • Authors: Mousaalreza Khalighi; Wannes Dermauw, Nicky Wybouw, Sabina Bajda, Masahiro Osakabe, Luc Tirry, Thomas Van Leeuwen
      Abstract: Background Cyenopyrafen is a recently developed acaricide with a new mode of action as complex II inhibitor. However, it was recently shown that cross‐resistance to cyenopyrafen can occur in resistant field strains of Tetranychus urticae, which might be linked to the previous use of classical METI acaricides. Here, we selected for cyenopyrafen resistance and studied the molecular mechanisms that underlie resistance. Results Selection to cyenopyrafen resistance confers cross‐resistance to the complex II inhibitor cyflumetofen, but also to pyridaben, a frequently used complex I inhibitor. Cyenopyrafen resistance is highly synergized by piperonylbutoxide, and a 15‐fold higher P450 activity was detected in the resistant strain. Target‐site resistance was not detected. Genome wide gene‐expression data, followed by a meta‐analysis of previously obtained gene expression data, revealed the over expression of specifically CYP392A11 and CYP392A12. Conclusions Cyenopyrafen resistance is strongly linked to the over expression of 2 P450s, which probably explains the observed cross‐resistance. This information is highly valuable, as the novel complex II inhibitors cyenopyrafen and cyflumetofen are in the process of worldwide registration. The role of both CYP392A11 and CYP392A12 should be further supported by functional expression, but they are very promising candidates as molecular diagnostic markers for monitoring cyenopyrafen susceptibility in the field.
      PubDate: 2015-06-26T00:36:15.831954-05:
      DOI: 10.1002/ps.4071
       
  • The potential of decision support systems to improve risk assessment for
           pollen beetle management in winter oilseed rape
    • Authors: Andrew W. Ferguson; Matthew P. Skellern, Andreas Johnen, Julia‐Sophie von Richthofen, Nigel P. Watts, Eileen Bardsley, Darren A. Murray, Samantha M. Cook
      Abstract: Background The reliance on and extensive use of pyrethroid insecticides has led to pyrethroid‐resistance in pollen beetle (Meligethes aeneus). Widespread adoption of best practice in pollen beetle management is therefore needed. Decision support systems (DSSs) that identify the risk period(s) for pest migration can help to target monitoring and control efforts but they must be accurate and labour‐efficient to gain the support of growers. Weather data and the phenology of pollen beetles in 44 winter oilseed rape crops across England over 4 years were used to compare the performance of two risk management tools: the DSS proPlant expert which predicts migration risk according to a phenological model and local weather data, and ‘rule‐based advice’ that depends on crop growth stage and a temperature threshold. Results Both risk management tools were effective in prompting monitoring that would detect breaches of various control thresholds. However, the DSS more accurately predicted migration start and advised significantly fewer days of migration risk, consultation days and monitoring than did rule‐based advice. Conclusion The proPlant expert DSS reliably models pollen beetle phenology. Use of such DSS can focus monitoring effort to when it is most needed, facilitate the practical use of thresholds and help to prevent unnecessary insecticide applications and the development of insecticide resistance.
      PubDate: 2015-06-26T00:27:00.600967-05:
      DOI: 10.1002/ps.4069
       
  • How active ingredient localisation in plant tissues determines the
           targeted pest spectrum of different chemistries
    • Authors: Anke Buchholz; Stefan Trapp
      Abstract: Background The efficacies of four commercial insecticides and of two research compounds were tested against aphids (Aphis craccivora and Myzus persicae), whiteflies (Bemisia tabaci) and red‐spotted spider mites (Tetranychus urticae) in intrinsic (oral administration), curative (direct contact spray) and translaminar (arthropods infested on untreated leaf underside) assays. With a new translaminar model, the transport across the leaf cuticle and tissues, and the electro‐chemical distribution of test compounds in cellular compartments and apoplast were calculated. Results The comparison of both information sets revealed that the intracellular localization of active ingredients determines the performance of test compounds against different target pests due to different feeding behaviours: Mites feed on mesophyll, aphids and whiteflies mostly in the vascular system. Polar compounds have a slow adsorption into leaf cells and thus a favourable distribution into apoplast and xylem sap . Slightly lipophilic bases get trapped in vacuoles, which is a less suited place to control Hemipteran pests but appropriate to control mites. Non‐favourable cellular localisation led to a strong reduction in translaminar efficacy against phloem‐feeders. Conclusion Prediction and optimization of intracellular localization of pesticides add valuable new information for targeted bioavailability and can indicate directions for improved pesticide design.
      PubDate: 2015-06-26T00:26:53.465149-05:
      DOI: 10.1002/ps.4070
       
  • Environmental Behavior and Analysis of Agricultural Sulfur
    • Authors: Corey M. Griffith; James E. Woodrow, James N. Seiber
      Abstract: Sulfur has been widely used for centuries as a staple for pest and disease management in agriculture. Presently, it is the largest volume pesticide in use worldwide. This review describes the sources and recovery methods for sulfur, its allotropic forms and properties, and its agricultural uses, including development and potential advantages of nanosulfur as a fungicide. Chemical and microbial reactivity, interactions in soil and water, and analytical methods for determination in environmental samples and foodstuffs, including inexpensive analytical methods for sulfur residues in wine, beer, and other food/beverage substrates, will be reviewed. The toxicology of sulfur towards humans and agriculturally important fungi is included, with some restrictions on use to promote safety. The review concludes with areas for which more research is warranted.
      PubDate: 2015-06-23T04:48:41.39292-05:0
      DOI: 10.1002/ps.4067
       
  • Molecular characterization of Bacillus thuringiensis strain MEB4 highly
           toxic to Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera:
           Pyralidae)
    • Authors: Abdelmalek Nouha; Sellami Sameh, Ben kridis Asma, Tounsi Slim, Rouis Souad
      Abstract: Background Cry2 proteins play an essential role in current Bacillus thuringiensis (Bt) applications and in the prevention of insect resistance to Cry1A toxins. This paper reports on the screening and characterization of novel Bt strains harboring effective cry2A‐type genes and higher insecticidal activity to Ephestia kuehniella. Results 29 native Bt strains were screened to search for the potent strain against E. kuehniella. The plasmid pattern of the selected strains showed interesting variability. The PCR‐RFLP analysis of two amplified regions showed high sequence identity within the selected cry2A‐type genes. SDS‐PAGE and Western‐Blot analysis revealed the presence of Cry2Aa toxin only in the MEB4 and BLB240 strains. The activation of Cry2Aa protoxins by larvae midgut juice, trypsin, or chymotrypsin enzymes revealed significant differences in terms of proteolysis profiles. Interestingly, a 49 kDa band was detected in the proteolysis pattern of BLB240, suggesting the presence of a chymotrypsin cleavage site that might have affected its insecticidal activity. Further, bioassays demonstrated that MEB4 (103.08 ± 36 µg g−1) was more active than BLB240 (153.77 ± 45.65 µg g−1) against E. kuehniella. Conclusion Based on its potent insecticidal activity, MEB4 strain could be considered an effective alternative agent for the control of E. kuehniella.
      PubDate: 2015-06-22T04:48:09.879317-05:
      DOI: 10.1002/ps.4066
       
  • Sublethal doses of fipronil intensify synapsin immunostaining in Atta
           sexdens rubropilosa brains (Hymenoptera, Formicidae)
    • Authors: P. Cintra‐Socolowski, T. C. Roat, R. C. F. Nocelli, P. H. Nunes, Ferreira R.A.C; O. Malaspina, O. C. Bueno
      Abstract: Background although ants are common insects in agricultural ecosystems, few studies have considered how xenobiotics might induce physiological and morphological alterations in these insects. This study aimed to verify the neurotoxic action of sublethal doses of fipronil on the mushroom bodies of brains from the leaf‐cutting ant Atta sexdens rubropilosa through immunocytochemistry analysis for the protein synapsin. Results The LD50 value was established as 1.42 ng / ant, and the sublethal doses used were LD 50/10 and LD 50/100.The synapsin labeling was more evident in the brains extracted from ants exposed to the insecticide, specifically in the regions of glia in the mushroom bodies, compared with the control group. It was possible to measure the intensity of emitted fluorescence in the areas of the mushroom bodies and the statistic test showed differences between the control group and the treatment group. Conclusion Thus, it is concluded that the sublethal doses of the insecticide fipronil intensified synapsin immunostaining, suggesting an increased release of neurotransmitters, which may be linked to neurotoxicity, and overexcitation. These sublethal doses may have two different impacts: compromising the operation and maintenance of the colony and leading to the establishment of resistance in insects.
      PubDate: 2015-06-22T04:07:30.135608-05:
      DOI: 10.1002/ps.4065
       
  • Larvicidal activity of Magnolia denudata seed hydrodistillate constituents
           and related compounds and liquid formulations towards two susceptible and
           two wild mosquito species
    • Authors: Zhang‐qian Wang; Haribalan Perumalsamy, Mo Wang, Shaohua Shu, Young‐Joon Ahn
      Abstract: Background Anopheles sinensis, Aedes aegypti and Aedes albopictus and Culex pipiens pallens mosquitoes transmit malaria, dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity of 17 constituents from Magnolia denudata seed hydrodistillate (MD‐SHD) and four experimental MD‐SHD liquid formulations (10–50 mg L−1 liquids) to third instar larvae from insecticide‐susceptible Cx, p. pallens and Ae. aegypti as well as wild Ae. albopictus and An. sinensis. Results 2, 4‐Di‐tert‐butylphenol was the most toxic constituent (LC50, 1.98–3.90 mg L−1), followed by linoleic acid (7.19–10.49 mg L−1) towards four mosquito species larvae. High toxicity was also produced by nerolidol, (±)‐limonene, α‐terpinene and γ‐terpinene (LC50, 9.84–36.42 mg L−1). The toxicity of these compounds was virtually identical towards four mosquito species larvae, even though An. sinensis larvae were resistant to deltamethrin and temephos. The MS‐SHD 50 mg L−1 liquid resulted in 92–100% control towards four mosquito species larvae while commercial temephos 200 g L−1 emulsifiable concentrate was almost ineffective towards An. sinensis larvae (30% mortality). Conclusion Reasonable mosquito control in the aquatic environment can be achieved by MD‐SHD 50 mg L−1 liquid as a potential larvicide.
      PubDate: 2015-06-18T02:18:01.226931-05:
      DOI: 10.1002/ps.4064
       
  • SAR activation in Solanaceous crops as a management strategy against
           root‐knot nematodes
    • Authors: Sergio Molinari
      Abstract: Background Activators of systemic acquired resistance (SAR), such as salicylic acid (SA) and its synthetic functional analogs, benzo(1,2,3)thiadiazole‐7‐carbothionic acid‐S‐methyl ester (BTH) and 2,6‐dichloroisonicotinic acid (INA), were tested on tomato, eggplant, and pepper for the control of the root‐knot nematode Meloidogyne incognita. Effects on plant fitness, nematode reproduction, and root galling were screened in relation to different methods of application, to different applied dosages of chemicals, and to different plant growth stages. Dosages applied to plants were in relation to plant weights. These chemicals were also tested for their possible nematotoxic activity in vitro. Results Soil drenches of SA and INA, and root dip application of SA and BTH, inhibited nematode reproduction, at specific dosage ranges, without affecting plant growth. SA and INA were able to reduce root galling as well. Foliar sprays of both SA and BTH were ineffective against nematode attacks. Plants tolerated SA more than the other chemicals tested. BTH at elevated concentrations increased the mortality of nematode juveniles and reduced egg hatching in vitro. Conclusions SAR activators at concentrations suitable for different plant growth stages and applied by the proper method can possibly be included in IPM programs for nematode management.
      PubDate: 2015-06-17T22:20:52.15349-05:0
      DOI: 10.1002/ps.4063
       
  • Short‐chain alkanes synergize responses of moth pests to their sex
           pheromones
    • Authors: Alexandre Gurba; Patrick M Guerin
      Abstract: Background The use of sex pheromones for mating disruption of moth pests of crops is increasing worldwide. Efforts are underway to augment the efficiency and reliability of this control method by adding molecules derived from host plants to the sex attractants in dispensers. Results We show how attraction of the European grapevine moth, Lobesia botrana Den. & Schiff., and the codling moth, Cydia pomonella L., males to under‐dosed levels of their sex pheromones is increased by adding heptane or octane, over a range of release rates. Pheromone‐alkane mixtures enhance male recruitment up to 30%, reaching levels induced by calling females and decrease the flight time to the sex attractant by a factor of two. Conclusion The findings open promising perspectives for the use of short‐chain alkanes as pheromone synergists for mating disruption of insect pests of food crops. Alkane‐pheromone combinations are expected to increase competitiveness of dispensers with females and to reduce the amount of pheromone needed for the control of these pests.
      PubDate: 2015-06-17T22:08:43.661296-05:
      DOI: 10.1002/ps.4061
       
  • Identification and Characterization of Two General Odorant Binding Protein
           from the Litchi Fruit Borer, Conopomorpha sinensis Bradley
    • Authors: Qiong Yao; Shu Xu, Yizhi Dong, Kai Lu, Bingxu Chen
      Abstract: Background The litchi fruit borer, Conopomorpha sinensis Bradley, is one of the most destructive pests of litchi and longan fruits in Southeast Asia and Southern China, yet the molecular biology and physiology of this pest remain poorly understood. Control of this insect pest may be achieved by interfering with its recognition of host plants. Results In this study, two cDNAs encoding CsGOBP1 and CsGOBP2 were identified from the antennae of C. sinensis, and a comparative study on these two C. sinensis GOBPs (CsGOBPs) was conducted. The secondary structure of these two CsGOBPs mainly consists of six α‐helices, but the three‐dimensional structural predictions of CsGOBP1 and CsGOBP2 indicated significant difference in the final 3D models. Results in Real‐time PCR assays indicated that the two CsGOBPs had different tissue‐ and sex‐dependent expression patterns. The competitive binding assay revealed that the CsGOBP1 considerably preferred the component exhibited in Guiwei or Feizixiao litchi cultivar, while CsGOBP2 bind to general volatile components from nine litchi cultivars. Additionally, Ethyl acetate has higher binding affinities with of CsGOBP2 protein than CsGOBP1, and has remarkable attraction to female C. sinensis moths in Y‐Tube olfactometer assay. Conclusion These results strongly suggest functional difference between these two CsGOBPs in perception of host plant odorants.
      PubDate: 2015-06-17T22:08:35.2105-05:00
      DOI: 10.1002/ps.4062
       
  • Metrafenone resistance in a population of Erysiphe necator in northern
           Italy
    • Authors: Andrea Kunova; Cristina Pizzatti, Maria Bonaldi, Paolo Cortesi
      Abstract: BACKGROUND Metrafenone has been used in Europe in integrated pest management programs since 2006 to control powdery mildews, including Erysiphe necator. Its exact mode of action is not known, but it is unique among fungicide classes used in powdery mildew management. Recently, resistance to metrafenone was reported in Blumeria graminis f.sp. tritici. In this study we investigated metrafenone resistance in Erysiphe necator in northern Italy. RESULTS Metrafenone efficacy to control grapevine powdery mildew was monitored in three consecutive years in field, and its reduced activity was observed in 2013. Out of thirteen monoconidial isolates, two sensitive strains were identified, which did not grow at fungicide concentration recommended for field application. The remaining strains showed variable response to metrafenone, and five of them grew and sporulated similarly to control even at 1250 mg L−1 of metrafenone. Moreover, the resistant strains showed cross‐resistance to pyriofenone, which belongs to the same FRAC group as metrafenone. CONCLUSION The results indicate the emergence of metrafenone resistance in an Italian population of Erysiphe necator. Further studies are needed to get an insight into the metrafenone's mode of action and to understand the impact of resistance on changes in the pathogen population structure, fitness and spread of resistant strains, which will be indicative for designing appropriate anti‐resistance measures.
      PubDate: 2015-06-15T05:35:20.952715-05:
      DOI: 10.1002/ps.4060
       
  • Characterization of GST genes from the Chinese white pine beetle
           Dendroctonus armandi (Curculionidae: Scolytinae) and their response to
           host chemical defense
    • Authors: Lulu Dai; Junning Ma, Mingyuan Ma, Zhang Haoqiang, Qi Shi, Ranran Zhang, Hui Chen
      Abstract: Background Bark beetles rely on their detoxifying enzymes to resist the defensive terpenoids of host trees. Glutathione S‐transferases conjugate xenobiotic compounds with a glutathione moiety (GSH) and often work in tandem with cytochromes P450 or other enzymes that aid in the detoxification, sequestration or excretion of toxic compounds. Result We identified nine new GST genes in the Chinese white pine beetle (Dendroctonus armandi) and carried out a bioinformatics analysis on the deduced full‐length amino acid sequences. These genes belong to four different classes (epsilon, sigma, omega and theta). Differential transcript levels of each class GST genes were observed between sexes, and within these levels, significant differences were found among the different adult sub‐stages that were fed phloem of Pinus armandi and exposed to six stimuli ((±)‐α‐pinene, (−)‐α‐ pinene, (−)‐β‐pinene, (+)‐3‐carene, (±)‐limonene and turpentine) at 8 and 24 h. Conclusion The increased transcription levels of GST genes suggested that they have some relationship with the detoxification of terpenoids that are released by host trees. The mediating oxidative stress that is caused by monoterpene might be the main role of the bark beetle GSTs.
      PubDate: 2015-06-15T05:27:47.286392-05:
      DOI: 10.1002/ps.4059
       
  • Genetic basis, evolutionary origin and spread of resistance to
           acetolactate synthase (ALS) inhibiting herbicides in common groundsel
           (Senecio vulgaris)
    • Authors: Christophe Délye; Romain Causse, Séverine Michel
      Abstract: Background Following control failure by herbicides inhibiting acetolactate‐synthase (ALS) in French wheat fields and vineyards, we aimed at confirming resistance evolution and investigating the evolutionary origin and spread of resistance in the tetraploid species Senecio vulgaris (common groundsel), a widespread, highly mobile weed. Results Sequencing two ALS homeologs in S. vulgaris enabled the first identification and characterisation of ALS‐based resistance in this species. Cross‐resistance patterns associated with Leu‐197 and Ser‐197 ALS1 were established using eight herbicides. Sequencing and genotyping showed that ALS‐based resistance evolved by multiple, independent appearances of mutant ALS1 and ALS2 alleles followed by spread. Spread of a mutant ALS1 allele issued from one particular appearance event was observed over 60 km. Independent resistance appearance events and easy seed dispersion are the most likely reasons for populations of S. vulgaris containing different mutant ALS alleles. Accumulation of different alleles likely due to sexual reproduction was observed in the same plant. Conclusion Mutant ALS alleles and possibly other mechanisms cause resistance to ALS inhibitors in S. vulgaris. Management strategies should aim at limiting S. vulgaris establishment and seed set. Considering the mobility of this species, control coordination at a regional level is clearly necessary if resistance spread is to be contained.
      PubDate: 2015-06-12T01:52:49.210345-05:
      DOI: 10.1002/ps.4058
       
  • Genetic basis of Spodoptera frugiperda (Lepidoptera: Noctuidae) resistance
           to the chitin synthesis inhibitor lufenuron
    • Authors: Antonio Rogério Bezerra do Nascimento; Juliano Ricardo Farias, Daniel Bernardi, Renato Jun Horikoshi, Celso Omoto
      Abstract: Background An understanding of the genetic basis of insect resistance to insecticides is important for the establishment of Insect Resistance Management (IRM) strategies. In this study we evaluated the inheritance pattern of resistance to the chitin synthesis inhibitor lufenuron in Spodoptera frugiperda. Results The LC50 values (95% CI) were 0.23 µg of lufenuron mL−1 of water (ppm) (0.18 – 0.28) for the susceptible strain (SUS) and 210.6 µg mL−1 (175.90 – 258.10) for the lufenuron‐resistant strain (LUF‐R) based on diet‐overlay bioassay. The resistance ratio was ≈ 915‐fold. The LC50 values for reciprocal crosses were 4.89 µg mL−1 (3.79 – 5.97) for female LUF‐R and male SUS and 5.74 µg mL−1 (4.70 – 6.91) for female SUS and male LUF‐R, indicating that the inheritance of S. frugiperda resistance to lufenuron is autosomal incompletely recessive. Backcrosses of the progeny of reciprocal crosses with the parental LUF‐R showed polygenic effect. The estimated minimum number of independent segregations ranged 11.02, indicating that resistance to lufenuron is associated with multiple genes in S. frugiperda. Conclusions Based on genetic crosses, the inheritance pattern of lufenuron resistance in S. frugiperda was autosomal, incompletely recessive and polygenic. Implications of this finding to IRM are discussed in this paper.
      PubDate: 2015-06-11T04:45:24.600473-05:
      DOI: 10.1002/ps.4057
       
  • The next generation of insecticides: dsRNA is stable as a foliar applied
           insecticide
    • Authors: Keri San Miguel; Jeffrey G. Scott
      Abstract: Background RNAi is a powerful tool used to study gene function. It also has been hypothesized to be a promising new method for control of insect pests on crops, although it has been suggested that instability of dsRNA in the environment could limit this new type of pest control. Results We confirmed that foliar application of Colorado potato beetle dsRNA actin is highly effective for control, demonstrated that treatment with actin‐dsRNA protects potato plants for at least 28 days weeks under greenhouse conditions, and found that the dsRNA is not readily removed by water once dried on the leaves. Conclusion These new results suggest that foliar application of dsRNA could be a valuable control strategy. Technological aspects of spraying dsRNA that need to be considered in the future are discussed.
      PubDate: 2015-06-11T04:45:23.188866-05:
      DOI: 10.1002/ps.4056
       
  • 4‐Phenylphenalenones as a template for new photodynamic compounds
           against Mycosphaerella fijiensis
    • Authors: William Hidalgo; Marisol Cano, Manuela Arbelaez, Edwin Zarrazola, Jesús Gil, Bernd Schneider, Felipe Otálvaro
      Abstract: Background Evaluation of 4‐phenylphenalenones and structural analogues against the fungal pathogen Mycosphaerella fijiensis (causal agent of black sigatoka disease in bananas) under light‐controlled conditions uncovered some key structural features for the design of photodynamic compounds. Results SAR analysis revealed the importance of a chromophoric aryl‐ketone and a “steroidomimetic” structural motif in the activity of the assayed compounds. The results pointed to the evaluation of 1,2‐dihydro‐3H‐naphtho[2',1':3,4]cyclohepta[1,2‐b]furan‐3‐one which displayed an activity in the range of propiconazole but with photodynamic behavior. Conclusion The present work demonstrates that 1,2‐dihydro‐3H‐naphtho[2',1':3,4]cyclohepta[1,2‐b]heterocyclic‐3‐one derivatives can be used as potential lead compounds for the development of fungicides which relies on a dual mode of action.
      PubDate: 2015-06-09T05:36:38.637853-05:
      DOI: 10.1002/ps.4055
       
  • On‐farm evaluation of inundative biological control of Ostrinia
           nubilalis (Lepidoptera: Crambidae) by Trichogramma brassicae (Hymenoptera:
           Trichogrammatidae) in three European maize producing regions
    • Authors: J. Razinger; V.P. Vasileiadis, M. Giraud, W. van Dijk, Š. Modic, M. Sattin, G. Urek
      Abstract: BACKGROUND A two‐year study was conducted to evaluate the efficacy of biological control with optimally timed Trichogramma brassicae releases as an integrated pest management tool against Ostrinia nubilalis (Hübner; ECB) in on‐farm experiments (i.e. real field conditions) in three European regions with dissimilar geo‐climatic conditions, ECB pressure, and conventional management (i.e. insecticide treated and untreated). RESULTS Biological control with Trichogramma 1) provided ECB protection comparable to the conventional management; 2) in all cases maintained mycotoxin levels below the EU threshold for maize raw materials destined for food products; 3) was economically sustainable in southern France and northern Italy, but not in Slovenia where it resulted in a significant decrease of gross margin, mainly due to the cost of Trichogramma product; and 4) enabled avoidance of detrimental environmental effects of lambda‐cyhalothrin use in northern Italy. CONCLUSION Optimally timed mass release of T. brassicae could be considered a sustainable tool for IPM programmes against ECB in southern France and northern Italy. Better involvement of regional advisory services is needed for the successful dissemination and implementation of biological control. Subsidy schemes could also motivate farmers to adopt this IPM tool and compensate for high costs of Trichogramma product.
      PubDate: 2015-06-05T04:02:04.730359-05:
      DOI: 10.1002/ps.4054
       
  • Detrimental effects of electron beam irradiation on the cowpea bruchid
           Callosobruchus maculatus
    • Authors: Wen Sang; Mickey Speakmon, Lan Zhou, Yu Wang, Chaoliang Lei, Suresh D. Pillai, Keyan Zhu‐Salzman
      Abstract: Background Electron beam (eBeam) irradiation technology is an environmentally‐friendly, chemical‐free alternative for disinfesting insect pests of stored grains. The underlying hypothesis was that specific doses of eBeam will have defined detrimental effects on the different life stages. We evaluated the effects of eBeam exposure at a range of doses (0.03 ‐ 0.12 kGy) on development of the cowpea bruchid (Callosobruchus maculatus) at various stages of its life cycle. Results Differential radiosensitivity was detected during egg development. Early and intermediate stages of eggs never hatched after exposure to the dose of 0.03 kGy, whereas a substantial portion of black‐headed (i.e. late) eggs survived irradiation even at 0.12 kGy. However, further development of the hatched larvae was inhibited. Although midgut protein digestion remained intact, irradiated larvae (0.06 kGy or higher) failed to develop into normal living adults, rather they died as pupae or abnormally eclosed adults, suggesting a detrimental effect of eBeam on metamorphosis. Emerged irradiated pupae had shorter longevity and were unable to produce any eggs at 0.06 kGy or higher. At this dose range, eggs laid by irradiated adults were not viable. eBeam treatment shortened adult longevity in a dose‐dependent manner. Reciprocal crosses indicated that females were more sensitive to eBeam exposure than their male counterparts. Dissection of female reproductive system revealed that eBeam treatment prevented formation of oocytes. Conclusion eBeam irradiation has very defined effects on cowpea bruchid development and reproduction. A dose of 0.06 kGy could successfully impede cowpea burchid population expansion. This information can be exploited for post‐harvest insect control of stored grains.
      PubDate: 2015-06-02T02:30:09.539136-05:
      DOI: 10.1002/ps.4053
       
  • Exploring Mechanisms of Resistance to Dimethachlone in Sclerotinia
           sclerotiorum
    • Authors: Md. Jahangir Firoz; Xiang Xiao, Fu‐Xing Zhu, Yan‐Ping Fu, Dao‐Hong Jiang, Guido Schnabel, Chao‐Xi Luo
      Abstract: BACKGROUND The dicarboximide fungicide dimethachlone has been widely used in China for more than 12 years to control the Sclerotinia stem rot caused by Sclerotinia sclerotiorum disease. First signs of resistance in the field are reported at low frequency. In this study, 4 resistant isolate/mutants were used to explore still unknown mechanisms leading to dimethachlone resistance. RESULTS The resistant isolate/mutants had significantly higher EC50 values compared to the sensitive control isolates. Cross resistance was confirmed between dimethachlone and procymidone, iprodione and fludioxonil. The resistant isolate/mutants revealed a decreased mycelial growth rate, were less pathogenic on leaves of oilseed rape, more sensitive to osmotic pressure and oxidative stress, and released more electrolytes compared to the sensitive isolates. Only in one lab mutant we found a point mutation (V238A) in the SsOs1 gene of the HOG (high osmolarity glycerol) signaling pathway. The expression of this gene was lost in the field resistant isolate HN456‐1‐JBJ and decreased in mycelium that was subjected to either high osmotic pressure or dimethachlone, but another key gene in HOG pathway, the SsHog1 could be induced in the resistant isolate and mutants with the treatment of NaCl. CONCLUSION This study demonstrates that resistance to dicarboximide fungicide dimethachlone in S. sclerotiorum is emerging in China. Several fitness parameters, including mycelia growth rate, sclerotia formed in vitro, aggressiveness on leaves, osmotic and H2O2 sensitivity indicate that the resistant strains may not effectively compete with sensitive isolates in the field in the absence of selection pressure. Lost expression or the V238A point mutation in the SsOs1 gene may confer resistance to dicarboximide fungicide dimethachlone in S. sclerotiorum but this study illustrates that also other, yet unknown mechanisms exist.
      PubDate: 2015-06-01T03:27:56.612973-05:
      DOI: 10.1002/ps.4051
       
  • Insecticide resistance in pollen beetles over seven years ‐ a
           landscape approach
    • Authors: Laura GA Riggi; Vesna Gagic, Riccardo Bommarco, Barbara Ekbom
      Abstract: Background Despite considerable interest on the impacts of pesticides on pest populations, few attempts have been made to link resistance patterns of insect pests to land‐use features across spatial and temporal scales. We hypothesize that pollen beetle pesticide resistance increase in areas with a high proportion of oilseed rape and with even mixtures of winter and spring oilseed rape, due to high pesticide selection pressure in such areas. Results Here, we investigated 7 years of lambda‐cyhalothrin (Karate®) resistance in field‐collected pollen beetle adults from a total of 180 sampling points across 10 regions in Sweden. We found a positive effect on pollen beetle pesticide resistance of the proportion oilseed rape and even spring‐winter oilseed rape mixture. However, this was true only for the regional spatial scale. Significant land‐use effects in the long term models, with oilseed rape data averaged over longer (4 years) periods of time, suggested an effect of regional landscape history on current pest resistance. Conclusion For successful control of pollen beetle pesticide resistance we suggest a long‐term regional strategy for oilseed rape management. This land‐use approach provides a framework for further investigations that integrate resistance management into landscape research.
      PubDate: 2015-06-01T01:24:41.930995-05:
      DOI: 10.1002/ps.4052
       
  • Combining Odours Isolated from Phylogenetically Diverse Sources Yields a
           Better Lure for Yellow Jackets
    • Authors: C. Rikard Unelius; D. Maxwell Suckling, Robert L. Brown, Julia K. Jósvai, Ashraf El‐Sayed
      Abstract: BACKGROUND Invasive wasps have major impacts on bird populations and other biodiversity in New Zealand beech forests and new solutions are needed for their management. Baits were combined from four phylogenetically diverse sources (protein and carbohydrate) to improve attraction to a level that could be used as the basis for more powerful attract‐and‐kill systems. Many compounds from honey, scale insect honeydew, fermenting brown sugar and green‐lipped mussels were highly attractive and when combined, outcompeted known attractants. RESULTS The equivolumetric lure (equal parts of 3‐methylbut‐1‐yl acetate: 2‐ethyl‐1‐butanol: 1‐octen‐3‐ol: 3‐octanone: methyl phenylacetate: heptyl butanoate), gave a 5–10 fold improvement over the known attractant, octyl butanoate, and other previously patented lures. An economically optimized lure of the same compounds, but with the ratio 2: 1.6: 1: 1: 2: 2.4, was equally attractive as the equal ratio lure. Pilot mass trapping attempts with this latter lure revealed that > 400 wasps per trap/day could be caught at the peak of the season. CONCLUSION The new lures are comprised of compounds from animals, plants and fungi, thus targeting the omnivorous behaviour of these wasps.
      PubDate: 2015-05-28T03:52:10.717873-05:
      DOI: 10.1002/ps.4050
       
  • Synthesis and Insecticidal Activity of β‐dihydroagarofuran
           Ether Analogues
    • Authors: Ximei Zhao; Zhan Hu, Jian Li, Longbo Li, Wenjun Wu, Jiwen Zhang
      Abstract: BACKGROUND 1β, 2β, 4α, 6α, 8β, 9α, 12‐hepthydroxyl‐β‐dihydroagarofuran is the main skeleton of β‐dihydroagarofuran sesquiterpenoids which exhibit excellent insecticidal activity. To further study the structure‐activity relationship of β‐dihydroagarofuran sesquiterpenoids towards finding novel botanical pesticides, two series of new structurally modified ether analogues were designed and synthesized, and their insecticidal activities were evaluated. RESULTS Twenty two ether derivatives were synthesized using 1β, 2β, 4α, 6α, 8β, 9α, 12‐hepthydroxyl‐β‐dihydroagarofuran as starting material. And The bioassay results indicated that most of the derivatives, particularly compounds 5.1.2, 5.1.3, 5.1.7, 5.2.3, 5.2.6 and 5.2.7, exhibited significant insecticidal activity against the 3rd instar larvae of M. srparata. Most importantly, compound 5.2.7 showed the lowest LD50 value of 29.2 ug/g among these synthesized compounds, which provides some important hints for further design, synthesis and structural modification of β‐dihydroagarofuran sesquiterpenoids towards developing novel botanical insecticides. CONCLUSION The structure‐activity relationship illustrated that the moiety at the 1‐position affected the insecticidal activity significantly, and that specifically, the derivatives with two or three carbon atoms at the 1‐position showed promising insecticidal activity with mortality over 60%, while those with o‐F‐Bn and p‐F‐Bn at the 6‐position showed similar activity.
      PubDate: 2015-05-28T03:46:48.239253-05:
      DOI: 10.1002/ps.4049
       
  • Molecular methods (digital PCR and real‐time PCR) for the
           quantification of low copy DNA of Phytophthora nicotianae in environmental
           samples
    • Authors: Josefa Blaya; Eva Lloret, Ana B. Santísima‐Trinidad, Margarita Ros, Jose A. Pascual
      Abstract: BACKGROUND Currently, real‐time polymerase chain reaction (qPCR) is the technique used most to quantify pathogen presence. Digital PCR (dPCR) is a new technique with the potential to have a substantial impact on plant pathology research due to its reproducibility, sensitivity and low susceptibility to inhibitors. In this study, we evaluated the feasibility of using dPCR and qPCR to quantify Phytophthora nicotianae in several background matrices, including host tissues (stems and roots) and soil samples. RESULTS In spite of the low dynamic range of dPCR (3 logs compared to 7 for qPCR), this technique proved to be very precise, this precision being applicable at very low copy numbers. The dPCR was able to detect accurately the pathogen in all type of samples in a broad concentration range. Moreover, dPCR seems to be less susceptible to inhibitors than qPCR in plant samples. Linear regression analysis showed a high correlation between the results obtained with the two techniques in soil, stem and root samples with R2=0.873, 0.999 and 0.995 respectively. CONCLUSIONS These results suggest that dPCR is a promising alternative for quantifying soil‐borne pathogens in environmental samples, even in early stages of the disease.
      PubDate: 2015-05-27T02:17:00.486157-05:
      DOI: 10.1002/ps.4048
       
  • Field resistance to the Bacillus thuringiensis protein Cry1Ac expressed in
           Bollgard® hybrid cotton in pink bollworm, Pectinophora gossypiella
           (Saunders), populations in India
    • Authors: Komarlingam S. Mohan; Kadanur C. Ravi, Pennadam J. Suresh, Douglas Sumerford, Graham P. Head
      Abstract: BACKGROUND Bollgard® cotton, expressing Cry1Ac insecticidal protein, was approved for commercial planting in India in 2002, and by 2009 constituted 87% of the Indian crop, reducing losses from lepidopteran pests including pink bollworm (PBW), Pectinophora gossypiella. Inadequate control of PBW in fields of single‐gene Bollgard cotton was reported in 2009; surveys revealed heavy infestations of PBW in Bollgard, restricted to Gujarat state, but not elsewhere in India. RESULTS Bioassays of PBW strains from Bollgard bolls showed that while susceptible PBW could not complete development to ≥3rd instar at 10.0 µg/ml Cry1Ac, 66.1% of larvae from Gujarat Bollgard strains could. A field‐resistant strain, further selected in the laboratory, had susceptibility to Cry1Ac reduced by >2000‐fold. Resistance to Cry1Ac did not confer cross‐resistance to the Cry2Ab2 protein. In 2010, Bollgard fields in Gujarat continued to be infested with PBW and many Bollgard fields in the adjoining states of Maharashtra and Madhya Pradesh showed high level infestation by PBW. CONCLUSION Inadequate planting of refuges for PBW is the likely explanation for the field resistance to Bt cotton observed in Gujarat. These findings underscore the higher vulnerability of single‐gene Bt products relative to dual‐gene products expressing Cry1Ac and Cry2Ab2, and the increased risk of resistance evolution with low refuge compliance.
      PubDate: 2015-05-27T02:16:57.566855-05:
      DOI: 10.1002/ps.4047
       
  • Targeted control of the saddle gall midge, Haplodiplosis marginata (von
           Roser) (Diptera: Cecidomyiidae), and the benefits of good control of this
           pest on winter wheat yield†
    • Authors: Florence Censier; Sandrine Chavalle, Gilles San Martin y Gomez, Michel De Proft, Bernard Bodson
      Abstract: BACKGROUND Since 2010, there has been a resurgence of the saddle gall midge, Haplodiplosis marginata (von Roser), in Belgium and several other European countries, with this pest sometimes causing severe damage in cereals. In 2012 and 2013, field trials were conducted in heavily infested fields to assess its impact on winter wheat crops and to determine efficient ways of dealing with severe infestations. RESULTS Crop exposure to H. marginata varied with the different protection methods tried. These methods included one to four successive applications of lambda‐cyhalothrin. Yield losses were significant, reaching 6% in 2012 and as high as 15% in 2013, and these losses were linearly related to the number of galls on stems. CONCLUSION The trials showed that insecticide applications needed to be synchronized with H. marginata flight peaks and to target the egg hatching period. They also revealed that insecticides applied to coincide with the first flight could, in humid conditions, also reach the larvae close to the soil surface, prior to their pupation.
      PubDate: 2015-05-26T05:06:53.216978-05:
      DOI: 10.1002/ps.4046
       
  • Retention Time of Chlorophacinone in Black‐Tailed Prairie Dogs
           Informs Secondary Hazards from a Prairie Dog Rodenticide Bait
    • Authors: Gary W. Witmer; Nathan P. Snow, Rachael S. Moulton
      Abstract: Secondary toxicity in mammals and birds that consume animals containing residues of anticoagulant rodenticides represents a persistent conflict among conservation, agriculture, and environmental contamination. Chlorophacinone residues in black‐tailed prairie dogs (Cynomys ludovivianus) represent a secondary exposure hazard to predatory and scavenging avian and mammalian species in the central plains, USA, and especially considering efforts to reestablish black‐footed ferrets (Mustela nigripes). Rozol® Prairie Dog Bait (chlorophacinone 0.005%) is registered to control black‐tailed prairie dogs in 10 states throughout the midwestern and western USA. We fed Rozol Prairie Dog Bait to captive black‐tailed prairie dogs for 2 days and analyzed their livers and whole‐bodies (without livers) for chlorophacinone residue on days 3, 5, 7, 9, 11, 14, 18, and 27 post‐exposure. We found the greatest levels of residues in livers (x¯= 5.499 mg kg −1) and whole‐bodies (x¯= 1.281 mg kg −1) on day 3. Residues in both tissues declined rapidly over time, with estimated half‐lives of approximately 6 days post‐exposure. However, a risk assessment of secondary toxicity to nontarget mammals indicated acute risks for mammalian species up to 27 days post‐exposure and negligible risks for birds. The results suggest that the greatest risk of secondary toxicity occur ≤14 days post‐application of Rozol Prairie Dog Bait and declines thereafter. This corresponds to the time when chlorophacinone residues are high, and prairie dogs exhibit signs of intoxication and are perhaps most susceptible to predation and scavenging. These results confirm that Rozol Prairie Dog Bait should not be used in areas where black‐footed ferrets or other sensitive species occur.
      PubDate: 2015-05-21T12:06:10.547917-05:
      DOI: 10.1002/ps.4045
       
  • Synthetic Pheromones as a management technique – Dispensers decrease
           Linepithema humile activity in a commercial vineyard
    • Authors: Fabian Ludwig Westermann; Vaughn Antony Bell, David Maxwell Suckling, Philip John Lester
      Abstract: BACKGROUND Invasive ants, such as the Argentine ant, have often been reported to facilitate honeydew‐producing hemipteran pests like mealybugs, which can be vectors of plant pathogens. Synthetic pheromones may offer a target‐specific method to control such ants and consequently lower the abundance of honeydew producing pests. Here we report the results of a trial to suppress Argentine ants in grape vines using ant pheromone dispensers. RESULTS Compared with untreated controls, we observed a significant drop in Argentine ant activity on the ground, irrespective of whether pheromone dispensers were placed at ground level, within the canopy or in both locations. Ant counts in the canopy confirmed that Argentine ant abundance was reduced under the influence of the pheromone dispenser placed at ground level compared with untreated controls. However, placing dispensers only in the canopy did not reduce the numbers of ants within the canopy compared with untreated controls. CONCLUSION Our results showed that pheromone dispensers can significantly reduce Argentine ant foraging in grape vines, if they are positioned appropriately. This technique could potentially reduce the abundance of associated mealybugs and potentially attendant virus vectoring area wide.
      PubDate: 2015-05-21T11:52:36.024775-05:
      DOI: 10.1002/ps.4043
       
  • Control methods against invasive Aedes mosquitoes in Europe: a review
    • Authors: Frédéric Baldacchino; Beniamino Caputo, Fabrice Chandre, Andrea Drago, Alessandra della Torre, Fabrizio Montarsi, Annapaola Rizzoli
      Abstract: Five species of invasive Aedes mosquitoes have recently become established in Europe: Aedes albopictus, Aedes aegypti, Aedes japonicus japonicus, Aedes koreicus and Aedes atropalpus. These mosquitoes are a serious nuisance for people and are also competent vectors for several exotic pathogens such as dengue and chikungunya viruses. As they are a growing public health concern, methods to control these mosquitoes need to be implemented to reduce their biting and their potential for disease transmission. There is a crucial need to evaluate methods as part of an integrated invasive mosquito species control strategy in different European countries, taking into account local Aedes infestations and European regulations. This review presents the control methods available or in development against invasive Aedes mosquitoes with a particular focus on those which can be implemented in Europe. These control methods are divided into five categories: environmental (source reduction), mechanical (trapping), biological (e.g. copepods, Bti, Wolbachia), chemical (insect growth regulators, pyrethroids) and genetic (sterile insect technique and genetically modified mosquitoes). We discuss the effectiveness, ecological impact, sustainability and stage of development of each control method.
      PubDate: 2015-05-21T07:20:54.867765-05:
      DOI: 10.1002/ps.4044
       
  • Can poisons stimulate bees? Appreciating the potential of hormesis in
           bee‐pesticide research
    • Authors: G. Christopher Cutler; Rachel R. Rix
      Abstract: Hormesis, a biphasic dose–response whereby exposure to low doses of a stressor can stimulate biological processes, has been reported in many organisms, including pest insects when they are exposed to low doses of a pesticide. However, awareness of the hormesis phenomenon seems to be limited among bee researchers, despite the increased emphasis of late on pollinator toxicology and risk assessment. In this commentary I show that there are nevertheless several examples in the literature of substances that are toxic to bees at high doses stimulating various biological processes at low doses. Appreciation of the hormetic dose–response by bee researchers will be useful to improve our fundamental understanding of how bees respond to low doses of chemical stressors, while advancing new perspectives for pollinator risk assessment.
      PubDate: 2015-05-19T02:36:26.762808-05:
      DOI: 10.1002/ps.4042
       
  • Electrical Penetration Graph technique as a tool to monitor early stages
           of aphid resistance to insecticides
    • Authors: Elisa Garzo; Aranzazu Moreno, Sara Hernando, Vera Mariño, María Torne, Mª Estrella Santamaria, Isabel Díaz, Alberto Fereres
      Abstract: BACKGROUND Sulfoxaflor, a new insecticide from the sulfoximine chemical family, and imidacloprid, a widely used neonicotinoid insecticide, were tested to assess the susceptibility and feeding behaviour of two populations of Myzus persicae: Mp61, that exhibited target site R81T resistance to neonicotinoids and Mp1989, a laboratory clone maintained since 1989 as a susceptible reference. RESULTS Imidacloprid LC50 value for Mp61 was 16 times higher than for Mp1989 showing a moderate level of resistance. Sulfoxaflor LC50 values for Mp61 and Mp1989 were much closer. The probing behaviour, as assessed by Electrical Penetration Graphs (EPG), of both populations was clearly altered by sulfoxaflor, which reduced the ability of aphids to find and feed from the phloem. Feeding behaviour of the susceptible Mp1989 was much more severely affected than the moderate resistant Mp61 population on imidacloprid treated plants. PCR assays of both aphid populations followed by DNA sequencing identified differences between populations in the point mutation in the ß‐subunit of nicotinamide‐acetylcholine receptor linked to the resistant gene against the neonicotinoid insecticide. CONCLUSIONS Sulfoxaflor provoked feeding cessation more rapidly than imidacloprid on both aphid populations. Sharp differences in feeding behaviour were detected between the susceptible and the moderate neonicotinoid‐resistant aphid populations. The EPG technique can be used as a useful tool to give new insights on the functional effects of new chemical compounds and for early detection of low to moderate levels of resistance of sap‐feeding insects to insecticides. The potential of this technique was validated by molecular analysis of the R81T mutation target site.
      PubDate: 2015-05-19T02:33:07.639047-05:
      DOI: 10.1002/ps.4041
       
  • Response to low‐dose herbicide selection in self‐pollinated
           Avena fatua
    • Authors: R. Busi; M Girotto, S.B. Powles
      Abstract: BACKGROUND Herbicides when applied at the correct plant stage and dose are highly toxic to plants. At reduced, low herbicide doses (below the recommended dose) plants can survive and display continuous and quantitative variation in dose‐survival responses. Recurrent (directional) selection studies can reveal whether such a phenotypic variation in plant survival response to low herbicide dose is heritable and leads to herbicide resistance. In a common experimental garden study, we have subjected a susceptible population of self‐pollinated hexaploid Avena fatua to low‐dose recurrent selection with the ACCase‐inhibiting herbicide diclofop‐methyl for three consecutive generations. RESULTS Significant differences in response to low‐dose diclofop‐methyl selection were observed between the selected progenies and parent plants with a two‐fold diclofop‐methyl resistance and cross‐resistance to ALS‐inhibiting herbicides. Thus, the capacity of self‐pollinated A. fatua to respond to low‐dose herbicide selection is marginal and it is much lower than in cross‐pollinated L. rigidum. Lolium rigidum in the same experiment evolved 40‐fold diclofop‐methyl resistance by progressive enrichment of quantitative resistance‐endowing traits. CONCLUSION Cross‐pollination rate, genetic variation and ploidy levels are identified as possible drivers affecting the contrasting capacity of Avena versus Lolium plants to respond to herbicide selection and the subsequent likelihood of resistance evolution at low herbicide dose usage.
      PubDate: 2015-05-18T07:35:18.956693-05:
      DOI: 10.1002/ps.4032
       
  • Benchmark study on glyphosate‐resistant cropping systems in the
           United States. Part 7: Effects of weed management strategy (grower
           practices versus academic recommendations) on the weed soil seedbank over
           6 years
    • Authors: David J. Gibson; Bryan G. Young, Micheal D. K. Owen, Karla L. Gage, Joseph L. Matthews, David L. Jordan, David R. Shaw, Stephen C. Weller, Robert G. Wilson
      Abstract: BACKGROUND Shifts in weed species composition and richness resulting from near exclusive reliance on herbicides in glyphosate‐resistant (GR) cropping systems has necessitated the implementation of alternative weed management tactics to reduce selection pressures of herbicides. We contrasted the response of the weed soil seedbank to effects of weed management strategy comparing grower practices to academic recommendations for best management practices (BMPs) over 6 years and across 5 weed hardiness zones in the US Midwest at sites subject to GR cropping systems. RESULTS Total weed population density and species richness varied according to cropping system, location, and prior year's crop, but less so to weed management strategy. The seedbank population density for 11 of the 14 most frequent weed species was affected by weed management strategy either alone or in an interaction with hardiness zone or year, or both. In only 29% of comparisons was weed population density lower following academic recommendations, and this depended upon prior crop and cropping system. The population density of high risk weed species was reduced by academic recommendations but only in two of six years and under continuous GR maize. Overall, the weed population density was decreasing in field halves subject to the BMPs in the academic recommendations relative to grower practices. CONCLUSION The soil seedbank is slow to respond to academic recommendations to mitigate glyphosate‐resistant weeds, but represents a biological legacy that growers need to keep in mind even when management practices reduce emerged field weed population densities. ©201X Society of Chemical Industry
      PubDate: 2015-05-14T07:46:28.440576-05:
      DOI: 10.1002/ps.4039
       
  • Behavioral response of spotted‐wing drosophila, Drosophila suzukii
           Matsumura, to aversive odors and a potential oviposition deterrent in the
           field
    • Authors: Anna K. Wallingford; Stephen P. Hesler, Dong H. Cha, Gregory M. Loeb
      Abstract: BACKGROUND Drosophilia suzukii Matsumura is an invasive pest insect that lays its eggs in the fruit of several commercially grown crops. An effective oviposition deterrent could contribute to its management. Repellant odors were evaluated in the laboratory and in the field. RESULTS Geosmin and 1‐octen‐3‐ol were found to be aversive to 7 d old female D. suzukii at concentrations of 10−1 and 10−2 in laboratory choice tests. Field experiments found that fewer eggs were observed in fruit on the day of harvest and fewer adult D. suzukii were reared from fruit associated with 1‐octen‐3‐ol odors than control fruit in cultivated red raspberry. CONCLUSION Geosmin and 1‐octen‐3‐ol induce aversive behaviors in Drosophila suzukii and are potential oviposition deterrents for its management in fruit crops.
      PubDate: 2015-05-14T07:46:25.674464-05:
      DOI: 10.1002/ps.4040
       
  • Target‐site EPSPS Pro‐106 mutations: sufficient to endow
           glyphosate resistance in polyploid Echinochloa colona?
    • Authors: Heping Han; Qin Yu, Michael J Widderick, Stephen B Powles
      Abstract: BACKGROUND This study confirms and characterises glyphosate resistance in two polyploid Echinochloa colona populations from north‐eastern Australia. RESULTS Glyphosate dose response revealed that the two resistant populations were marginally (up to 2‐fold) resistant to glyphosate. Resistant plants did not differ in non‐target‐site foliar uptake and translocation of 14C‐glyphosate but contained the known target‐site EPSPS mutation Pro‐106‐Thr and/or Pro‐106‐Leu. Although plants carrying either a single or two EPSPS mutations were glyphosate‐resistant relative to the susceptible population, they were still controlled at the field rate of glyphosate (450 g a.e. ha−1) when treated under warm conditions (25/20 °C). However, when treated in hot conditions (35/30 °C), most mutant resistant plants (68%) can survive the field rate, and an increase (2.5 fold) in glyphosate LD50 was found for both the R and S populations. CONCLUSIONS This study shows that one or two EPSPS Pro‐106 mutations are insufficient in conferring field‐rate glyphosate resistance in polyploidy E. colona at mild temperatures. However, control of these mutant plants at the glyphosate field rate is poor at high temperatures, likely due to reduced glyphosate efficacy. Therefore, glyphosate should be applied during relatively mild (warm) temperature periods in the summer growing season to improve E. colona control.
      PubDate: 2015-05-12T12:33:39.047196-05:
      DOI: 10.1002/ps.4038
       
  • Soil ecotoxicity assessment of glyphosate use under field conditions:
           microbial activity and community structure of Eubacteria and ammonia
           oxidizing bacteria
    • Authors: María C. Zabaloy; Ignacio Carné, Rodrigo Viassolo, Marisa A. Gómez, Elena Gomez
      Abstract: BACKGROUND A plot‐scale experiment was conducted to assess the impact of field application rates of glyphosate on soil microbial communities, by taking measures of microbial activity (substrate‐induced respiration and enzyme activity) in parallel with culture‐independent approaches to assess both bacterial abundance and diversity. Two rates of glyphosate, alone or in mixture with 2,4‐dichlorophenoxyacetic acid (2,4‐D), were applied directly onto the soil surface, simulating normal use in chemical fallow in no‐till systems. RESULTS No consistent rate‐dependent responses were observed in the microbial activity parameters investigated in the field‐plots that were exposed to glyphosate. Denaturant gradient gel electrophoresis (DGGE) of the overall bacterial community (Eubacteria) and ammonia oxidizing bacteria (AOB) revealed no effects of the high rate of glyphosate on the communities’ structure, in comparison with the control. No treatment effects were observed on the abundance of Eubacteria shortly after treatment in 2010, while a small but significant difference between the high rate and the control was detected in the first sampling in 2011. The abundance of AOB was relatively low during the study and treatment effects were undetectable. CONCLUSIONS The absence of negative effects on soil microbial communities in this study suggest that glyphosate use at recommended rates poses low risk to the microbiota.
      PubDate: 2015-05-09T08:05:39.699392-05:
      DOI: 10.1002/ps.4037
       
  • Insecticide resistance status of Myzus persicae in Greece: long term
           surveys and new diagnostics for resistance mechanisms.
    • Authors: Costas Ch. Voudouris; Amalia N. Kati, Eldem Sadikoglou, Martin Williamson, Panagiotis Skouras, Ourania Dimotsiou, Stella Georgiou, Brian Fenton, George Skavdis, John T. Margaritopoulos
      Abstract: Background Myzus persicae nicotianae is an important pest in Greece controlled mainly by neonicotinoids. Monitoring of the aphid populations for resistance mechanisms is essential for effective control. Results Two new RFLP‐based diagnostics for the detection of the M918T (super‐kdr pyrethroid resistance) and nAChR R81T (neonicotinoid resistance) mutations were applied, along with other established assays, on 131 nicotianae multilocus genotypes (MLGs) collected from tobacco and peach in Greece in 2012–2013. Furthermore, we present resistance data from aphid clones (>500, mainly nicotianae) collected in 2006–2007. About half of the clones tested with a diagnostic dose of imidacloprid were tolerant. The R81T mutation was not found in the 131 MLGs and 152 clones examined. Over half (58.6 %) of a subset of 29 clones showed a 9–36 fold over‐expression of CYP6CY3. M918T was found at low to moderate frequencies. The kdr and MACE mechanisms, and carboxylesterace‐based resistance were found at high frequency in all years. Conclusion The aphid retains costly resistance mechanisms even in the absence of pressure from certain insecticides which could be attributed to factors related to climate, and genetic properties of the populations. The indication of built‐ up of neonicotinoid neonicotinoids, related to CYP6CY3 over‐expression, is a matter of concern.
      PubDate: 2015-05-09T07:56:09.086813-05:
      DOI: 10.1002/ps.4036
       
  • Insecticidal efficacy and persistence of a co‐occluded binary
           mixture of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) variants in
           protected and field‐grown tomato crops in the Iberian Peninsula
    • Authors: Maite Arrizubieta; Oihane Simón, Luis M. Torres‐Vila, Elisabete Figueiredo, F. Javier Mendiola, Antonio Mexia, Primitivo Caballero, Trevor Williams
      Abstract: BACKGROUND A binary co‐occluded mixture (HearSP1B:LB6) of Helicoverpa armigera single nucleopolyhedrovirus (HearNPV) variants was previously found to be highly pathogenic under laboratory conditions. The insecticidal efficacy and persistence of this mixture were determined in greenhouse and field‐grown tomato crops in Spain and Portugal. RESULTS Concentrations of 109 – 1011 OBs L−1 of HearSP1B:LB6 resulted in 89‐100% mortality of larvae on treated tomato plants in growth chambers. In protected tomato crops, application of 1010 OBs L−1 of HearSP1B:LB6 was as effective as Bacillus thuringiensis (Bt) and spinosad in reducing the percentage of damaged fruits, and resulted in higher larval mortality than the Bt treatment. In open‐field tomato crops virus‐treatments were as effective in reducing the percentage of damaged fruit as spinosad, Bt and chlorpyrifos treatments. The persistence of the insecticides on tomato plants was negatively correlated with solar radiation in both field and greenhouse settings. Residual insecticidal activity of OBs on protected tomato crops at 6 days post‐application was 55% and 35% higher than that of Bt and spinosad, respectively. On field‐grown tomato, OB persistence was significantly lower than that of spinosad or chlorpyrifos. CONCLUSION The efficacy and persistence of HearSP1B:LB6 OBs was comparable to that of commercial insecticides in both field and greenhouse tomato crops. Future studies should focus on reducing application rates to determine insecticidal efficacy at lower OB concentrations.
      PubDate: 2015-05-09T07:56:06.491889-05:
      DOI: 10.1002/ps.4035
       
  • Field Evolved Resistance to Four Modes of Action of Herbicides in A Single
           Kochia (Kochia scoparia L Schrad.) Population
    • Authors: VK Varanasi; AS Godar, RS Currie, JA Dille, CR Thompson, PW Stahlman, J Mithila
      Abstract: BACKGROUND Evolution of multiple herbicide resistance in weeds is a serious threat to weed management in crop production. Kochia is an economically important broadleaf weed in the US Great Plains. The study aimed to confirm resistance to four sites of action of herbicides in a single kochia population from a crop field near Garden City (GC) Kansas (KS), USA, and further determine the underlying mechanisms of resistance. RESULTS One‐fourth of the GC plants survived the labelled rate or higher of atrazine (PSII‐inhibitor) and the surviving plants had the Ser‐264 to Gly mutation in the psbA gene, the target site of atrazine. Ninety percent of GC plants survived labeled rate of dicamba, a synthetic auxin. At least 87% of the plants survived up to 72 g a.i. ha−1 chlorsulfuron (acetolactate synthase (ALS)‐inhibitor) and the analysis of the ALS gene revealed the presence of Pro‐197‐Thr and/or Trp‐574‐Lue mutation(s). Most GC plants also survived labeled rate of glyphosate (5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS) inhibitor) and the resistant plants had five to nine EPSPS gene copies (relative to the ALS gene). CONCLUSION We confirm the first case of evolution of resistance to four herbicide sites of action (PSII‐, ALS‐, EPSPS‐inhibitors, and synthetic auxins) in a single kochia population and target‐site based mechanisms confer resistance to atrazine, glyphosate, and chlorsulfuron.
      PubDate: 2015-05-06T22:25:28.461608-05:
      DOI: 10.1002/ps.4034
       
  • Laboratory and field evaluations of camptothecin sodium salt against
           phytophagous mites
    • Authors: Sen‐Miao Tong; Ming‐Guang Feng
      Abstract: BACKGROUND Camptothecin (CPT), a monoterpene indole alkaloid from Camptotheca acuminate (Nyssaceae), is toxic to some insect pests but insoluble in water. Here we show that an aqueous CPT‐Na+ solution can kill the phytophagous mites Tetranychus urticae (TU), Acaphylla theae (AT) and Brevipalpus obovatus (BO) under laboratory and field conditions. RESULTS Modeling of 10‐day time‐concentration‐mortality responses of female adults to 2‐mL tower sprays of three CPT‐Na+ dilutions generated LC50s and LT50s decreasing over post‐spray days and sprayed amounts respectively. CPT‐Na+ sprays required to kill 50% BO, TU and AT were 35, 41 and 124 µg mL−1 on day 1 post‐spray but rapidly decreased to 2.2, 2.5 and 3.6 µg mL−1 on day 5, and to 0.69, 0.77 and 1.17 µg mL−1 on day 7 respectively. In summer field trials, a spray rate of 7.5 g CPT‐Na+ ha−1 provided better control efficacy against TU (81–85%) on cotton or AT (90–93%) and BO (83–88%) in tea gardens than aramite (commercial acaricide) at the labeled rate of 56.25 g ha−1. Half of the CPT‐Na+ rate controlled the mites as effectively as aramite. CONCLUSION Water‐soluble CPT‐Na+ is a promising plant‐sourced acaricide to combat wide‐spectrum pest mites.
      PubDate: 2015-04-29T21:45:57.704826-05:
      DOI: 10.1002/ps.4033
       
  • Azole fungicides – understanding resistance mechanisms in
           agricultural fungal pathogens
    • Authors: Claire L. Price; Josie E. Parker, Andrew G. S. Warrilow, Diane E. Kelly, Steven L. Kelly
      Abstract: Plant fungal pathogens can have devastating effects on a wide range of crops, including cereals and fruit (such as wheat and grapes), causing losses in crop yield, which are costly to the agricultural economy and threaten food security. Azole antifungals are the treatment of choice, however, resistance has arisen against these compounds, which could lead to devastating consequences. Therefore, it is important to understand how these fungicides are used and how the resistance arises to fully tackle the problem. Here, we give an overview of the problem and discuss the mechanisms that mediate azole resistance in agriculture (point mutations in the CYP51 amino acid sequence, overexpression of the CYP51 enzyme and overexpression of genes encoding efflux pumps proteins).
      PubDate: 2015-04-27T04:58:01.521766-05:
      DOI: 10.1002/ps.4029
       
  • Binding of the respiratory chain inhibitor Ametoctradin to mitochondrial
           bc1 complex
    • Authors: Marcus Fehr; Antje Wolf, Gerd Stammler
      Abstract: Background Ametoctradin is an agricultural fungicide that inhibits mitochondrial bc1 complex of oomycetes. The bc1 complex has two quinone binding sites that can be addressed by inhibitors. Depending on their binding sites and binding modes, the inhibitors show different degrees of cross‐resistance that need to be considered when designing spray programs for agricultural fungicides. The binding site of Ametoctradin was unknown. Results Cross‐resistance analyses, the reduction of isolated Pythium sp. bc1 complex in the presence of different inhibitors and molecular modelling studies were used to analyze the binding site and binding mode of Ametoctradin. All three approaches provide data supporting the argument that Ametoctradin binds to the Pythium bc1 complex similar to Stigmatellin. Conclusion The binding mode of Ametoctradin differs from other agricultural fungicides like Cyazofamid and the Strobilurins. This explains the lack of cross‐resistance with Strobilurins and related inhibitors, where resistance is mainly caused by the G143A amino acid exchange. Accordingly, mixtures or alternating applications of these fungicides and Ametoctradin can help to minimize the risk for the emergence of new resistant isolates.
      PubDate: 2015-04-27T04:52:08.423894-05:
      DOI: 10.1002/ps.4031
       
  • Sublethal effects of the insecticidal fusion protein
           ω‐ACTX‐Hv1a/GNA on the parasitoid Eulophus pennicornis
           via its host Lacanobia oleracea
    • Authors: Erich YT Nakasu; Filitsa Karamaouna, Georgios K. Partsinevelos, Hesham M. Abd El Halim, Elaine C Fitches, Prashant Pyati, John A. Gatehouse, Angharad MR Gatehouse, Martin G Edwards
      Abstract: BACKGROUND The neurotoxin peptide ω‐ACTX‐Hv1a, fused to the carrier molecule GNA presents potential for insect control as a biopesticide, being orally toxic to insect pests from different orders. However, thorough evaluation is required to assure its safety towards non‐target invertebrates. Effects of this novel biopesticide on the parasitoid Eulophus pennicornis via its host Lacanobia oleracea are presented. RESULTS Hv1a/GNA did not cause mortality when injected or fed to 5th stage L. oleracea, but caused up to 39% reduction in mean larval weight (p  0.05). The fusion protein was degraded by parasitoid larvae, rendering it non‐toxic. CONCLUSION Hv1a/GNA has negligible effects on the parasitoid, even under worst‐case scenarios. This low toxicity to these insects is of interest in terms of biopesticide specificity and safety to non‐target organisms.
      PubDate: 2015-04-27T04:46:01.28529-05:0
      DOI: 10.1002/ps.4030
       
  • Novel platensimycin derivatives with herbicidal activity
    • Authors: Fernanda C. Moraes; Elson S. Alvarenga, Kariny. B. Amorim, Antonio J. Demuner, Milton E. P. Flores
      Abstract: BACKGROUND Faced with the need to develop herbicides with different modes of action due to weed resistance to existing herbicides, the sesquiterpene lactones can be the starting point for the search of new bioactive compounds. Lumisantonin 5 and five novel amides 11–15 have been evaluated against two monocotyledons and three dicotyledons. RESULTS An efficient and versatile synthesis of lumisantonin (5) and five novel amides 11–15 have been accomplished from the readily available α‐santonin. These compounds were subjected to evaluation for their biological activity against Sorghum bicolor (sorghum), Allium cepa (onion), Cucumis sativus (cucumber), Solanum lycopersicum (tomato), and Bidens pilosa (beggartick). The compound 5 has inhibited the development of the aerial parts of sorghum and onion by 76% and 67% at 1000 μM respectively. The compound 12 has prevented the growth of shoots and radicles of sorghum by 80% and 71% at 1000 μM respectively. CONCLUSION All of the tested compounds have been found to exhibit promising seed germination inhibition. We can conclude that lumisantonin (5) was on average the most lethal against all plant species evaluated, however the compounds 12 and 14 have presented inhibition selectivity against monocotyledons when compared to dicotyledons.
      PubDate: 2015-04-24T02:22:15.303464-05:
      DOI: 10.1002/ps.4028
       
  • VKOR‐variant and sex are the main influencing factors on
           bromadiolone tolerance of house mouse (Mus musculus L.)
    • Authors: Tanja Šćepović; Goran Jokić, Alexandra Esther, Dragan Kataranovski, Petar Vukša, Suzana Đedović, Marina Vukša
      Abstract: Background After reports of management problems in practice, a survey was conducted to determine the presence of bromadiolone resistant animals in different house mouse (Mus musculus L.) populations in Serbia. A 21‐day no‐choice feeding test was carried out to examine the resistance of house mice to bromadiolone. Eighty house mice collected from 4 locations (10 males and 10 females per location) were tested for bromadiolone tolerance. Surviving animals and their F1 offspring were screened for mutations. The influence of VKOR‐variant, zygosity and sex on bromadiolone tolerance were analysed. Results Bait intake and changes in body weight revealed different animal responses regarding susceptibility or resistance. Leu128Ser, Tyr139Cys and a new Ala21Thr polymorphism were detected in wild‐born survivors and their F1 generation. However, not every individual with the polymorphism Leu128Ser and Tyr139Cys survived the feeding test. VKOR‐variants and sex caused variations in bromadiolone tolerance. Conclusion For the first time it was shown that the VKOR‐variant, along with sex, is responsible for bromadiolone tolerance in house mice. Other factors, including sex specific ones, influencing bromadiolone tolerance cannot be excluded. The tolerance levels of VKOR variants should be determined in further studies in order to evaluate the effectivness of bromadiolone in sustainable management.
      PubDate: 2015-04-22T04:12:15.996363-05:
      DOI: 10.1002/ps.4027
       
  • A pyrosequencing‐based method to quantify genetic substitutions
           associated with resistance to SDHI‐fungicides in Botrytis spp.
           populations
    • Authors: Mélanie Gobeil‐Richard; David‐Mathieu Tremblay, Carole Beaulieu, Hervé Van der Heyden, Odile Carisse
      Abstract: BACKGROUND The genetic underlying resistance mechanisms in the population of the phytopathogenic fungus Botrytis cinerea are well documented. Specifically, several genetic substitutions associated with SDHIs‐based fungicide resistance were identified in the succinate dehydrogenase gene. The objective of this work was to develop a molecular tool for accurate quantification of these genetic substitutions within Botrytis populations. A test using the PyroMark Q24 instrument was designed to detect and quantify five genetic substitutions associated with SDHIs resistance. RESULTS The technique is based on sequencing by synthesis and generated quantitative and accurate data with a limit of quantification of a minimum of 500 spores. There was a linear relationship between known and estimated percent of spore with the targeted genetic substitutions and wild‐type strains at ratios of 0%–100%, with 20% increment. CONCLUSION With the pyrosequencing assay developed in this study, a large number of Botrytis spp. individuals can be characterized in a timely fashion with greater accuracy than commonly used methods. Hence, pyrosequencing‐based methods will be useful to improve our understanding of fungicide resistance, detect arrival of new genetic substitutions, monitor shifts in fungal populations, assess the effectiveness of anti‐resistance strategies and for routine monitoring of fungicide resistance.
      PubDate: 2015-04-21T00:48:08.920301-05:
      DOI: 10.1002/ps.4026
       
  • Pesticides and reduced‐risk insecticides, native bees and
           Pantropical stingless bees: pitfalls and perspectives
    • Authors: Wagner F Barbosa; Guy Smagghe, Raul Narciso C Guedes
      Abstract: Although invertebrates generally have a low public profile, the honey bee, Apis mellifera L., is a flagship species whose popularity likely derives from the products it provides and its perceived ecological services. Therefore, the raging debate regarding honey bee decline has surpassed the realm of beekeepers, academia, industry and regulatory agencies and now also encompasses non‐governmental agencies, media, fiction writers and the general public. The early interest and concern about honey bee colony collapse disorder (CCD) soon shifted to the bigger issue of pollinator decline, with a focus on the potential involvement of pesticides in such a phenomenon. Pesticides were previously recognized as the potential culprits of the reported declines, particularly the neonicotinoid insecticides due to their widespread and peculiar use in agriculture. However, the evidence for the potential pivotal role of these neonicotinoids in the honey bee decline remains a matter of debate, with an increased recognition of the multifactorial nature of the problem and the lack of a direct association between the noted decline and neonicotinoid use. The focus on the decline of honey bee populations subsequently spread to other species, and bumble bees became another matter of concern, particularly in Europe and the US. Other bee species, ones that are particularly important in other regions of the world, remain the object of little concern (unjustifiably so). Furthermore, the continuous focus on neonicotinoids is also in need of revision, as the current evidence suggests that a broad spectrum of compounds deserve attention. Here we address both shortcomings.
      PubDate: 2015-04-17T04:32:21.341529-05:
      DOI: 10.1002/ps.4025
       
  • The degradation rate of thiamethoxam in European field studies
    • Authors: Martin J. Hilton; Tim D. Jarvis, Dean C. Ricketts
      Abstract: Background Thiamethoxam is a systemic and contact pesticidal active substance in the neonicotinoid class of insecticides, used world‐wide to control a range of insects. Recently, concerns have been expressed regarding possible effects of neonicotinoids to bees and other wildlife. The DT50 of thiamethoxam in soil may be crucial to assessing the potential long‐term exposure of non‐target organisms to thiamethoxam. There are currently no detailed publicly available data for the field soil degradation of thiamethoxam under European conditions. We publish field soil DT50 values of thiamethoxam from studies conducted in several European locations, under a range of realistic agronomic conditions. Results Field soil DT50 values normalized to 20 °C ranged between 7.1 – 92.3 days (geomean = 31.2 days; n = 18). Conclusion The degradation rate of thiamethoxam was not significantly affected by application type, cropped fields vs. bare soil, soil pH, organic matter content, or repeated annual applications. Soil photolysis and leaching were negligible; therefore calculated DT50 values were concluded to represent microbial degradation. The field degradation rates of thiamethoxam are faster than those previously reported from laboratory degradation studies. They demonstrate that thiamethoxam will degrade to concentrations
      PubDate: 2015-04-17T04:26:03.744961-05:
      DOI: 10.1002/ps.4024
       
  • Inheritance of field‐relevant resistance to the Bacillus
           thuringiensis protein Cry1Ac in Pectinophora gossypiella (Lepidoptera:
           Gelechiidae) collected from India
    • Authors: Rupa Nair; Subray P Kamath, Komarlingam S Mohan, Graham Head, Douglas V. Sumerford
      Abstract: BACKGROUND The inheritance and phenotypic expression of resistance to Bacillus thuringiensis Cry1Ac‐insecticidal protein were studied in selected populations of pink bollworm, Pectinophora gossypiella (Saunders), that were collected from Bollgard cotton in India. The individual populations in the pool were Cry1Ac‐resistant and sourced from Cry1Ac‐containing Bt cotton (Bollgard) hybrids in 2010. RESULTS Laboratory selection on diet with 1.0 µg/ mL of Cry1Ac protein increased the percentage reaching ≥ third instars from 7% in the F3 generation to 94% in the F15 generation, a 257‐fold increase in median lethal concentration relative to the susceptible strain. The analysis of reciprocal genetic crosses between the Cry1Ac‐resistant strain NKJ and a susceptible laboratory strain MRC showed dominance (h) of 0.22 indicating that the inheritance of Cry1Ac‐resistance is partially recessive at Cry1Ac concentrations comparable to those in Bollgard. Analyses of backcrosses of F1 hybrid moths with NKJ and MRC indicated that resistance is autosomal. The Cry1Ac‐resistant strain exhibited little or no cross‐resistance to the Cry2Ab2 protein. CONCLUSION This is the first study of the dominance of Cry1Ac field‐resistance in P. gossypiella. The results provide the basis for refining resistance management strategies for Bt cotton.
      PubDate: 2015-04-13T01:57:18.94754-05:0
      DOI: 10.1002/ps.4023
       
  • Effect of Solution and Leaf Surface Polarity on Droplet Spread Area and
           Contact Angle
    • Authors: Justin J Nairn; W Alison Forster, Rebecca M van Leeuwen
      Abstract: BACKGROUND How much an agrochemical spray droplet spreads on a leaf surface can significantly influence efficacy. This study investigates the effect solution polarity has on droplet spreading on leaf surfaces and whether the relative leaf surface polarity, as quantified using the wetting tension dielectric (WTD) technique, influences the final spread area. Contact angles and spread areas were measured using four probe solutions on 17 species. RESULTS Probe solution polarity was found to affect the measured spread area and the contact angle of the droplets on non hairy leaves. Leaf hairs skewed the spread area measurement preventing investigation of the influence of surface polarity on hairy leaves. WTD measured leaf surface polarity of non‐hairy leaves was found to strongly correlate with the effect of solution polarity on spread area. CONCLUSIONS For non‐polar leaf surfaces the spread area decreases with increasing solution polarity, for neutral surfaces polarity has no effect on spread area, and for polar leaf surfaces the spread area increase with increasing solution polarity. These results attest to the use of the WTD technique as a means to quantify leaf surface polarity.
      PubDate: 2015-04-10T03:17:20.595564-05:
      DOI: 10.1002/ps.4022
       
  • Evidence of a target resistance to antivitamin K rodenticides in the roof
           rat Rattus rattus: Identification and characterization of a novel Y25F
           mutation in the Vkorc1 gene
    • Authors: Joffrey Goulois; Audrey Chapuzet, Véronique Lambert, Nolan Chatron, Luba Tchertanov, Lionel Legros, Etienne Benoît, Virginie Lattard
      Abstract: BACKGROUND Despite intensive use of Bromadiolone, rodent control was inefficient in a farm in Zaragoza (Spain) infested by rats. While metabolic resistance was previously described in this rodent species, the observation of a target resistance to vitamin K rodenticides had been poorly documented in Rattus rattus. RESULTS From rats trapped in the farm, cytochrome b and Vkorc1 gene were amplified by PCR and sequenced in order to identify species and detect potential Vkorc1 mutations. VKORC1 deduced amino acids sequences were thus expressed in Pichia pastoris and inhibition constants towards various rodenticides were determined. The 10 rats trapped in the farm were all identified as Rattus rattus. They were found to be homozygous for the g.74A>T nucleotide replacement in exon 1 of the Vkorc1 gene leading to p.Y25F mutation. This mutation led to increase in Ki towards various rodenticides probably caused by a partial loss of helical structure of TM4. CONCLUSION The p.Y25F mutation detected in Vkorc1 gene in Rattus rattus trapped in the Spanish farm is associated to the resistance phenotype to bromadiolone that has been observed. It is the first evidence of target resistance to AVKs in Rattus rattus.
      PubDate: 2015-04-07T02:15:35.679398-05:
      DOI: 10.1002/ps.4020
       
  • EPSPS gene amplification in glyphosate‐resistant Bromus diandrus
    • Authors: Jenna M Malone; Sarah Morran, Neil Shirley, Peter Boutsalis, Christopher Preston
      Abstract: BACKGROUND Glyphosate is the most widely used herbicide in the World and has been intensively used to control B. diandrus, a problematic weed of crops and pastures in southern Australia. RESULTS Resistance to glyphosate was identified in two populations of B. diandrus that were nearly 5‐fold more resistant to glyphosate than wild type plants. Both populations contained EPSPS gene amplification, with resistant plants having an average of around 20 fold the number of copies of EPSPS compared with susceptible plants. EPSPS expression was also increased in resistant plants of both populations; however, expression levels were not correlated with the number of EPSPS copies. Amplification of only one of the four EPSPS genes present in B. diandus was detected. Investigation into the inheritance of glyphosate resistance found no segregation in the F2 generation. Every individual in the F2 populations contained between three and 30 copies of EPSPS; however, on average they contained fewer copies compared with the parent resistant population. CONCLUSIONS Glyphosate resistance in B. diandrus is due to EPSPS gene amplification. Resistance is heritable, but complex.
      PubDate: 2015-04-06T07:55:56.031411-05:
      DOI: 10.1002/ps.4019
       
  • Design, Synthesis, Antiviral Activity and 3D‐QSAR Study of Novel
           1,4‐Pentadien‐3‐one Derivatives Containing the
           1,3,4‐Oxadiazole Moiety
    • Authors: Xiuhai Gan; Deyu Hu, Pei Li, Jian Wu, Xuewen Chen, Wei Xue, Baoan Song
      Abstract: BACKGROUND 1,4‐Pentadien‐3‐one and 1,3,4‐oxadiazole derivatives possess good antiviral activities, their substructure units are usually used in antiviral agent design. In order to discover novel molecules with high antiviral activities, a series of 1,4‐pentadien‐3‐one derivatives containing the 1,3,4‐oxadiazole moiety were designed and synthesized. RESULTS Bioassays showed that most of the title compounds exhibited good inhibitory activities against tobacco mosaic virus (TMV) in vivo. In particular, compound 8f possessed the best protective activity against TMV, with EC50 value of 135.56 mg L−1, which were superior to ribavirin (435.99 mg L−1). The comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) of 3D‐QSAR with respect to the protective activities were studied with the values of q2 and r2 for CoMFA and CoMSIA model were 0.751, 0.775 and 0.936, 0.925 respectively. Compound 8 k was designed and synthesized based on the 3D‐QSAR model, and bioassay showed better protective activity (EC50, 123.53 mg L−1) than 8 f. CONCLUSION Some of the title compounds displayed good antiviral activities. 3D‐QSAR models revealed that the appropriate compact electron‐withdrawing and hydrophobic group at the benzene ring could enhance antiviral activity. These results could provide important structural insights for the design of highly active 1,4‐pentadien‐3‐one derivatives.
      PubDate: 2015-04-06T07:54:53.847995-05:
      DOI: 10.1002/ps.4018
       
  • Dual effects of Metarhizium spp. and Clonostachys rosea against an insect
           and a seed borne pathogen in wheat
    • Authors: Chad A. Keyser; Birgit Jensen, Nicolai V. Meyling
      Abstract: BACKGROUND Crops are often prone to both insect herbivory and disease which necessitate multiple control measures. Ideally an efficacious biological control agent must adequately control the target organism and not be inhibited by other biological control agents when applied simultaneously. Wheat seeds infected with the plant pathogen Fusarium culmorum were treated with Metarhizium brunneum or M. flavoviride and Clonostachys rosea individually and in combination with the expectation to control both root‐feeding insects and the pathogen. Emerging roots were evaluated for disease and then placed with Tenebrio molitor larvae which were monitored for infection. RESULTS Plant‐disease symptoms were nearly absent for seeds treated with C. rosea, both individually and in combination with Metarhizium spp. Furthermore, roots grown from seeds treated with Metarhizium spp. caused significant levels of fungal infection in larvae when used individually or combined with C. rosea. However, co‐treated seeds showed reduced virulence towards T. molitor as compared to treatments with Metarhizium spp. only. CONCLUSIONS This study clearly shows that seed treatments with both the entomopathogenic fungus M. brunneum and the mycoparasitic fungus C. rosea can protect plant roots from insects and disease. The dual‐treatment approach to biological control presented here harmonizes well with the ideals of IPM strategies.
      PubDate: 2015-04-01T04:21:09.422338-05:
      DOI: 10.1002/ps.4015
       
  • Spray distribution evaluation of different setting of a hand‐held
           trolley sprayer used in greenhouse tomato crops
    • Authors: Jordi Llop; Emilio Gi1, Montserrat Gallart, Felipe Contador, Mireia Ercilla
      Abstract: Background Hand‐held trolley sprayers have been recently promoted to improve techniques of spray application on greenhouses in south‐eastern Spain. However, certain aspects remain to be improved. A modified hand‐held trolley sprayer was evaluated under two different canopy conditions (high and low canopy density) and with several sprayer settings (nozzle type, air assistance, and spray volume). In this study, the deposition, coverage, and uniformity of distribution of the spray on the canopy have been assessed. Results The deposition on leaves was significantly higher when flat fan nozzles and air assistance were used at both high and low spray volumes. No differences were detected between the reference system at a high spray volume and the modified trolley at a low spray volume. Flat fan nozzles with air assistance increased penetrability into the canopy. Conclusions Air assistance and flat fan nozzles allow volume rates to be reduced while maintaining or improving spray quality distribution. The working parameters of hand‐held sprayers must be considered to reduce environmental risk and increase the efficacy of the spraying process.
      PubDate: 2015-04-01T04:20:58.435208-05:
      DOI: 10.1002/ps.4014
       
  • Efficacy and Environmental Fate of Imazapyr from Directed Helicopter
           Applications Targeting Tamarix Species Infestations in Colorado, USA
    • Authors: Cameron H Douglass; Scott J Nissen, Andrew R Kniss
      Abstract: Background Aerial imazapyr applications are the most common and cost effective method for controlling invasive tamarisk, but few studies have investigated whether or how infestation and site characteristics influence control and non‐target impacts. This study used vertical stands with filter papers, plus soil and tree canopy sampling to investigate how tamarisk canopies affected retention of applied imazapyr, soil herbicide residues and tree mortality. Results Tamarisk canopies captured 71% of aerially‐applied imazapyr, resulting in significantly lower soil residues beneath the tree canopy. Although initial imazapyr soil residue levels outside the tree canopy were four times greater than those inside, soil degradation occurred 2.4x faster outside the tamarisk canopy and resulted in lower herbicide residues. Tamarisk mortality within three years was 70%, but variability in control appeared to be affected by non‐linear stand boundaries and tall site obstructions. These same factors also increased variability in the actual quantity of herbicide applied, exacerbating collateral impacts on desirable understory species. Conclusion While aerial imazapyr applications are highly effective in controlling tamarisk, our study provides evidence for the importance of evaluating overall site suitability for this management strategy so the probability of unintended ecological effects can be minimized.
      PubDate: 2015-04-01T04:20:54.867494-05:
      DOI: 10.1002/ps.4016
       
  • High resolution melt and morphological analyses of mealybugs (Hemiptera:
           Pseudococcidae) from cacao: tools for the control of Cacao Swollen Shoot
           Virus spread
    • Authors: Andy Wetten; Colin Campbell, Joël Allainguillaume
      Abstract: BACKGROUND Mealybugs (Hemiptera: Coccoidea: Pseudococcidae) are key vectors of badnaviruses, including Cacao Swollen Shoot Virus (CSSV) the most damaging virus affecting cacao (Theobroma cacao L.). The effectiveness of mealybugs as virus vectors is species dependent and it is therefore vital that CSSV resistance breeding programmes in cacao incorporate accurate mealybug identification. In this work the efficacy of a CO1‐based DNA barcoding approach to species identification was evaluated by screening a range of mealybugs collected from cacao in seven countries. RESULTS Morphologically similar adult females were characterised by scanning electron microscopy and then, following DNA extraction, were screened with CO1 barcoding markers. A high degree of CO1 sequence homology was observed for all 11 individual haplotypes including those accessions from distinct geographical regions. This has allowed for the design of a High Resolution Melt (HRM) assay capable of rapid identification of the commonly encountered mealybug pests of cacao. CONCLUSIONS HRM Analysis (HRMA) readily differentiated between mealybug pests of cacao that can not necessarily be identified by conventional morphological analysis. This new approach, therefore, has potential to facilitate breeding for resistance to CSSV and other mealybug transmitted diseases.
      PubDate: 2015-04-01T04:20:51.241202-05:
      DOI: 10.1002/ps.4017
       
  • Development of selectable marker‐free transgenic potato plants
           expressing cry3A against the Colorado potato beetle (Leptinotarsa
           decemlineata Say)
    • Authors: Wen‐chao Guo; Zhi‐an Wang, Xiao‐li Luo, Xin Jin, Jing Chang, Jiang He, Er‐xun Tu, Ying‐chuan Tian, Huai‐jun Si, Jia‐he Wu
      Abstract: BACKGROUND Elimination of selectable marker genes (SMGs) is important for the safe assessment and commercial use of transgenic plants. The destructive and invasive Colorado potato beetle (CPB) poses a serious threat to potato production. In response to this need, selectable marker‐free transgenic potato lines expressing cry3A were developed to control the damage and spread of CPB. RESULTS We simultaneously introduced cry3A and npt II genes harboured in different plasmids into the potato genome using the Agrobacterium‐mediated co‐transformation method. Four selectable marker‐free transgenic potato (CT) lines expressing cry3A were developed by self‐crossing segregation and molecular analyses, including Southern blot, Western blot and enzyme‐linked immunosorbent assay (ELISA) assays. CT lines were used in a resistance bioassay against CPB in the laboratory and field. In the laboratory, CT lines exhibited high resistance to CPB and 100% mortality of 1st instar larvae occurred 6 days after infestation. In the field, untransformed plant leaves were almost entirely consumed with an average of 155 larvae present per plant 25 days after inoculation. However, CT lines showed no damage symptoms with approximately 2.5 larvae surviving per plant. CONCLUSION We successfully eliminated the SMG from the transgenic potato lines expressing cry3A, which can decrease CPB damage, control the spread of this pest eastwards and alleviate the concern regarding the safe assessment of regulatory requirements.
      PubDate: 2015-03-26T03:17:16.826399-05:
      DOI: 10.1002/ps.4013
       
  • Lactones 47. Synthesis, antifeedant and antibacterial activity of
           γ‐lactones with p‐methoxyphenyl substituent
    • Authors: Marcelina Mazur; Andrzej Skrobiszewski, Witold Gładkowski, Magdalena Podkowik, Jacek Bania, Jan Nawrot, Tomasz Klejdysz, Czesław Wawrzeńczyk
      Abstract: BACKGROUND Lactones are well known because of their biological activity. The grosheimin and repin are potent deterrents against storage pests. The unsaturated lactones exhibited wide spectrum of antibacterial activity. In our study we focused on synthesis and evaluation of biological activity of anisaldehyde derivatives containing lactone function. RESULTS Four new lactones were synthesized in one‐step reductive dehalogenation or dehydrohalogenation reactions. These compounds together with halolactones synthesized earlier (1, 3, 7, 8) were tested for their antifeedant activity toward the Sitophilus granaries, Trogoderma granarium and Tribolium confusum. The results of the tests proved that the highest activity, comparable with azadirachtin, towards all tested pests (T in the range 143.3‐183.9) was observed for lactone with vinyl substituent (6). Antibacterial activity of those compounds was also evaluated. The most potent lactone (2) was active towards Gram‐positive bacteria strains. CONCLUSIONS The results of biological tests proved that removing of halogen atom significantly increased the antifeedant properties of γ‐lactones with p‐methoxyphenyl substituent. The unsaturated lactones 5, 6 are the most promising ones in the context of possible industrial application of these compounds as the crops protecting agents. Further structural modifications of lactones with aromatic ring are needed to find important structural factors increasing the antibacterial activity.
      PubDate: 2015-03-25T01:27:38.130576-05:
      DOI: 10.1002/ps.4012
       
  • Insecticide resistance alleles in wetland and residential populations of
           the West Nile virus vector Culex pipiens in New Jersey, USA
    • Authors: Brian J. Johnson; Dina M. Fonseca
      Abstract: BACKGROUND Despite the extensive use of insecticides to control Culex pipiens in the aftermath of West Nile virus, knowledge of the spatial distribution and frequency of insecticide resistance in this species is poorly understood in the United States. This paper reports on the occurrence of upregulated esterases that detoxify organophosphates (OP) and mutations conferring resistance to pyrethroid insecticides in natural and developed areas of New Jersey (USA). RESULTS We report the first observations of the OP resistance alleles, EsterB1 and Ester2, and the classical knockdown resistance (kdr) mutation, L1014F, in New Jersey Cx. pipiens. Upregulated EsterB1 peaked at 23% (Mean±SE=12 ± 2.3%) and Ester2 at 14% (8 ± 1.8%) and both were widely distributed. L1014F, which confers strong resistance to pyrethroids when homozygous, was also widely distributed and ranged in frequency from 2‐19% (5.1% heterozygous individuals and 1.4% homozygous). CONCLUSION We demonstrate that OP resistance is common and broadly distributed in New Jersey Cx. pipiens and that homozygous individuals resistant to pyrethroids are present. Further, we detected double mutants at Ester and kdr, a condition that may annul the purging effects of insecticide rotations. Our results therefore indicate the need for continued monitoring of insecticide resistance in order to achieve effective mosquito control.
      PubDate: 2015-03-25T01:27:26.998089-05:
      DOI: 10.1002/ps.4011
       
  • Design, Synthesis, Antiviral Activity and Mode of Action of
           Phenanthrene–Containing N‐Heterocyclic Compounds Inspired from
           Phenanthroindolizidine Alkaloid Antofine
    • Authors: Xiuling Yu; Peng Wei, Ziwen Wang, Yuxiu Liu, Lizhong Wang, Qingmin Wang
      Abstract: BACKGROUND Phenanthroindolizidine alkaloid antofine and its analogues have excellent antiviral activity against tobacco mosaic virus (TMV). To simplify the structure and the synthesis hardness of phenanthroindolizidine alkaloid, a series of phenanthrene–containing N‐heterocyclic compounds 1–33 were designed and synthesized based on the intermolecular interaction of antofine and TMV RNA and systematically evaluated for their anti‐TMV activity. RESULT Most of these compounds exhibited good to reasonable anti‐TMV activity. The optimum compounds 5, 12 and 21 displayed higher activity than the lead compound antofine and commercial ribavirin. Compound 12 was chosen for the field trials of antiviral efficacy against TMV, and found to exhibit better activity than control plant virus inhibitors. Compounds 5 and 12 were chosen for mode of action studies. The changes of fluorescence intensity of 5 and 12 on separated TMV RNA showed that these small molecules can also bind to TMV RNA, but the mode is much different from that of antofine. CONCLUSION The compounds combining phenanthrene and N‐heterocyclic ring could maintain the anti‐TMV activity of phenanthroindolizidines, but their modes of action are different from that of antofine. Present study lays a good foundation for us to find more efficient anti‐plant virus reagents.
      PubDate: 2015-03-24T03:39:23.252475-05:
      DOI: 10.1002/ps.4008
       
  • Managing the evolution of herbicide resistance
    • Authors: Jeffrey A. Evans; Patrick J. Tranel, Aaron G. Hager, Brian Schutte, Chenxi Wu, Laura A. Chatham, Adam S. Davis
      Abstract: BACKGROUND Understanding and managing the evolutionary responses of pests and pathogens to control efforts is essential to human health and survival. Herbicide‐resistant (HR) weeds undermine agricultural sustainability, productivity, and profitability, yet the epidemiology of resistance evolution – particularly at landscape scales – is poorly understood. We studied glyphosate‐resistance (GR) in a major agricultural weed, Amaranthus tuberculatus (common waterhemp) using landscape, weed, and management data from 105 central Illinois grain farms, including over 500 site‐years of herbicide application records. RESULTS GR A. tuberculatus occurrence was greatest in fields with frequent glyphosate applications, high annual rates of herbicide mechanisms of action (MOA) turnover, and few MOAs field−1 year−1. Combining herbicide MOAs at the time of application by herbicide mixing reduced the likelihood of GR A. tuberculatus. CONCLUSIONS These findings illustrate the importance of examining large scale evolutionary processes at relevant spatial scales. Although measures such as herbicide mixing may delay GR or other HR weed traits, they are unlikely to prevent them. Long‐term weed management will require truly diversified management practices that that minimize selection for HR traits.
      PubDate: 2015-03-24T03:35:34.304571-05:
      DOI: 10.1002/ps.4009
       
  • Comparative and synergistic activity of Rosmarinus officinalis L.
           essential oil constituents against the larvae and an ovarian cell line of
           the cabbage looper, Trichoplusia ni (Lep., Noctuidae)
    • Authors: Jun‐Hyung Tak; Eduardo Jovel, Murray B. Isman
      Abstract: BACKGROUND Plant essential oils are usually complex mixtures, and many factors can affect their chemical composition. To identify relationships between composition and bioactivity of the constituents, comparative and synergistic interactions of the major constituents of rosemary essential oil were evaluated against third instar larvae and an ovarian cell line of the cabbage looper, Trichoplusia ni via different methods of application. RESULTS The major constituents of the rosemary oil we used were 1,8‐cineole, (±)‐camphor, (+)‐α‐pinene and camphene. Via topical application to larvae, 1,8‐cineole was identified as the major active compound, whereas via fumigation, 1,8‐cineole and (±)‐camphor, and in a cytotoxicity assay, (+)‐α‐pinene, were determined to be the major active principles. Several combinations of these constituents exhibited synergistic insecticidal activities when topically applied, particularly among combinations of three major constituents, (±)‐camphor, (+)‐α‐pinene, and camphene. A binary mixture of 1,8‐cineole and (±)‐camphor showed enhanced activity, with a synergy ratio of 1.72. CONCLUSION Based on our results, the insecticidal activity of rosemary oil appears to be a consequence of the synergistic interaction between 1,8‐cineole and (±)‐camphor, and (±)‐camphor should be considered a promising synergizing agent.
      PubDate: 2015-03-24T03:35:18.008443-05:
      DOI: 10.1002/ps.4010
       
  • Development of a regulatory testing procedure to study the metabolism of
           pesticides in farmed fish
    • Authors: Christian Schlechtriem; Ina Goeritz, Cornelia Atorf, Elena Bergendahl, Paul Seymour, Paul Whalley
      Abstract: Background Diets used in commercial fish farming use significant proportions of crop derived commodities and it is important to understand the potential for transfer of any pesticide residues on the crop into edible tissues in fish. It is a current requirement in the EU that fish metabolism studies must be performed when a pesticide is used in crops where commodities or processed fractions are fed to farmed fish. Fish metabolism studies in both rainbow trout and common carp have been carried out, following the new working document on nature of pesticed residues in fish using 14C labelled pesticide. Results The ingestion of the experimental diets by rainbow trout and common carp resulted in the uptake and metabolism of the test item as shown by liquid scintillation counting (LSC) analysis in combination with radio‐TLC analysis. Species specific differences in the chromatographic profile of pesticide metabolites were observed regarding the proportional distribution of metabolites rather than their general pattern. Conclusions Metabolism studies for regulatory purposes can be carried out with both fish species under laboratory conditions. The experimental design reported is suitable to quantify the transfer of residues to edible tissues and to enable characterisation of the chemical nature of residues.
      PubDate: 2015-03-20T05:52:24.481287-05:
      DOI: 10.1002/ps.4007
       
  • Broad resistance to AHAS‐inhibiting herbicides in feral radish
           (Raphanus sativus L.) populations from Argentina
    • Authors: Claudio E Pandolfo; Alejandro Presotto, Florencia Moreno, Ida Dossou, Juan P Migasso, Ernesto Sakima, Miguel Cantamutto
      Abstract: BACKGROUND Soon after the commercial release of sunflower cultivars resistant to imidazolinone herbicides (IMI), several uncontrolled feral radish (Raphanus sativus L.) populations were found in southeastern Buenos Aires, Argentina. These populations were studied in field, glasshouse and laboratory experiments aiming to characterize their resistant profile and to develop management tools. RESULTS Three feral radish accessions were highly resistant to ten active ingredients of five families of acetohydroxyacid synthase (AHAS) inhibiting herbicides. Sequence analysis of the AHAS gene detected a Trp574Leu mutation in all resistant accessions. One accession with an intermediate level of resistance was heterozygous for this mutation, probably due to gene exchange with a susceptible sub‐population located in the field margin. Herbicide resistant and susceptible radish could be controlled in sunflower by alternative herbicides. CONCLUSION This is the first report of feral radish with resistance to herbicides belonging to all the AHAS‐inhibiting herbicide families, conferred by Trp574Leu mutation in the AHAS gene. An appropriate herbicide rotation with alternative herbicides such as fluorochloridone or aclonifen, and an increase in the diversity of cropping systems is important to minimize the prevalence of these biotypes.
      PubDate: 2015-03-19T12:17:59.964993-05:
      DOI: 10.1002/ps.4006
       
  • Glyphosate resistance in Echinochloa colona: phenotypic characterization
           and quantification of selection intensity
    • Authors: Goh Sou Sheng; Martin M Vila‐Aiub, Roberto Busi, Stephen B Powles
      Abstract: BACKGROUND A population of Echinochloa colona infesting agricultural fields in the northern region of Western Australia evolved glyphosate resistance after 10 years of glyphosate selection. This study identified two phenotypic (susceptibility ‘S’ vs resistance ‘R’) lines from within a segregating glyphosate‐resistant population. Estimation of survival, growth and reproductive rates of the phenotypes in response to glyphosate selection helped characterize the level of resistance, fitness and the selection intensity for glyphosate in this species. RESULTS Estimations of LD50 (lethal dose) and GR50 (growth rate) have shown a 8‐fold glyphosate resistance in this population. The resistant index based on the estimation of seed number (SYn50) shows a 13‐fold resistance. As a result of linear combination of plant survival and fecundity rates, plant fitness of 0.2 and 0.8 was estimated for the S and R phenotypes when exposed to the low dose of 270 g glyphosate ha−1. At the recommended dose of 540 g glyphosate ha−1 fitness significantly decreased 5‐fold in S plants but remained markedly similar (0.7) in plants of the R phenotype. Thus, the calculated selection intensity (SI) at 540 g glyphosate ha−1 was much greater (SI = 17) than at 270 g glyphosate ha−1 (SI = 4). CONCLUSIONS The assessment of plant survival and fecundity in response to glyphosate selection in the S and R phenotypes allowed a greater accuracy in the estimation of population fitness of both phenotypes and thus the glyphosate selection intensity in E. colona. The estimation of seed number or mass of phenotypes under herbicide selection is a true ecological measure of resistance with implications for herbicide resistance evolution.
      PubDate: 2015-03-17T01:46:15.500606-05:
      DOI: 10.1002/ps.4005
       
  • Effects of CO2 dissolution on phase distribution and degradation of
           dimethyl disulfide (DMDS) in soils under grape production
    • Authors: Jeremy L. Conkle; J. Alfonso Cabrera, John Thomas, Dong Wang, Jay Gan
      Abstract: Background Dimethyl disulfide (DMDS) is a fumigant recently registered in parts of U.S. The fumigant has high pesticidal activity, but does not disperse in soils as well as other fumigants. This study assessed the use of CO2 as a propellant to improve soil dispersion and diffusion by evaluating the partitioning and degradation of DMDS after carbonation in four vineyard soils collected in California. Results The soil with the highest organic carbon content (Clarksburg) had highest soil‐water partition coefficient (Kd) (p 
      PubDate: 2015-03-13T02:16:21.251902-05:
      DOI: 10.1002/ps.4004
       
  • Using satellite multispectral imagery for damage mapping of armyworm
           (Spodoptera frugiperda) in maize at a regional scale
    • Authors: Jingcheng Zhang; Yanbo Huang, Lin Yuan, Guijun Yang, Liping Chen, Chunjiang Zhao
      Abstract: BACKGROUND Armyworm, as a destructive insect for maize, causes wide range of damage to both China and U.S. in recent years. To obtain the spatial distribution of damage area and access the damage severity, a fast and accurate loss assessment method is of great importance for effective administration. The objective of this study was to determine suitable spectral features for armyworm detecting and to develop a mapping method at regional scale based on satellite remote sensing image data. RESULTS The armyworm infestation could cause significant change in plant's leaf area index, which serves as a basis of infestation monitoring. Within a number of vegetation indices (VIs) that were examined for their sensitivity to the insect damage, the Modified Soil‐Adjusted Vegetation Index (MSAVI) was identified as the optimal VI for detecting armyworm. The univariate model that relies on two‐date satellite images significantly outperformed the multivariate model, with the overall accuracy increased from 0.50 to 0.79. CONCLUSION A mapping method for monitoring the armyworm infestation at a regional scale was developed based on univariate model and two‐date multispectral satellite images. The successful application of this method in a typical armyworm outbreak event in Tangshan, Hebei Province, China demonstrated the feasibility of the method and showed its promising potential to be implemented in practice.
      PubDate: 2015-03-11T10:28:04.512979-05:
      DOI: 10.1002/ps.4003
       
  • Supplemental food for Amblyseius swirskii in the control of thrips:
           feeding friend or foe?
    • Authors: Dominiek Vangansbeke; Duc Tung Nguyen, Joachim Audenaert, Ruth Verhoeven, Bruno Gobin, Luc Tirry, Patrick De Clercq
      Abstract: Background In IPM systems in greenhouse crops, the predatory mite Amblyseius swirskii is becoming increasingly important as a biological control agent of various pests, especially thrips and whiteflies. An emerging strategy to promote the predator's establishment and retention in the crop consists of providing food supplements. However, when faced with omnivorous pests, such as the western flower thrips, Frankliniella occidentalis, food supplements need to be applied with extreme care, in order not to boost population growth of the pest. This laboratory study was conducted to evaluate the impact of commercial products of Typha angustifolia pollen and decapsulated brine shrimp cysts (Artemia sp.) on populations of both pest and predator and on predator–prey interactions. Results Pollen was highly supportive for both F. occidentalis and A. swirskii, whereas Artemia cysts supported thrips populations to a lesser extent than those of the predator. Furthermore, a less pronounced reduction in thrips consumption by A. swirskii was observed in the presence of Artemia cysts as compared with T. angustifolia pollen. Conclusion Artemia might be a valuable alternative to pollen for supporting populations of A. swirskii in order to improve thrips management, as they are less beneficial for the pest but do support population growth of A. swirskii.
      PubDate: 2015-03-05T06:22:21.732527-05:
      DOI: 10.1002/ps.4000
       
  • Nematicidal activity of allyl bromide and dibromo(nitro)methane under
           laboratory conditions
    • Authors: Yuji Oka; Shimshon Shuker, Nadia Tkachi
      Abstract: BACKGROUND Restrictions on soil fumigants are prompting the development of new compounds for controlling nematodes, other soilborne pathogens and weeds. We evaluated nematicidal activity of five bromine compounds against Meloidogyne javanica in vitro, and tested the two most effective ones against Pratylenchus penetrans and Xiphinema index in vitro and in soil. RESULTS Only allyl bromide and dibromo(nitro)methane showed nematicidal activity against M. javanica juveniles in vitro at
      PubDate: 2015-03-05T06:22:06.705865-05:
      DOI: 10.1002/ps.4001
       
  • Evaluation of entomopathogenic nematodes and the supernatants of the
           in‐vitro culture medium of their mutualistic bacteria for the
           control of the root‐knot nematodes Meloidogyne incognita and M.
           arenaria
    • Authors: Ilker Kepenekci; Selcuk Hazir, Edwin E. Lewis
      Abstract: BACKGROUND The suppressive effect of various formulations of four entomopathogenic nematode (EPN) species and the supernatants of their symbiotic bacteria on the root‐knot nematodes (RKN), Meloidogyne incognita and M. arenaria in tomato roots were evaluated. The EPNs Steinernema carpocapsae, S. feltiae, S. glaseri and Heterorhabditis bacteriophora were applied as either live infective juveniles (IJs) or infected insect cadavers. Spent medium from culturing the bacterial symbionts Xenorhabdus bovienii and Photorhabdus luminescens kayaii with the cells removed was also applied without their nematode partners. RESULTS The aqueous suspensions of IJs, infected cadaver applications of EPNs, and especially treatments of X. bovienii supernatant suppressed the negative impact of RKN on tomatoes. Specific responses to treatment were reduced RKN egg masses, increased plant height, and increased fresh and dry weights compared with the control where only RKNs were applied. CONCLUSION Among the treatments tested, the plant‐dipping method of X. bovienii into bacterial culture fluid may be the most practical and effective method for M. incognita and M. arenaria control.
      PubDate: 2015-02-27T01:51:58.912456-05:
      DOI: 10.1002/ps.3998
       
  • Transgenic cabbage plants with a synthetic cry1Ia8 gene from Bacillus
           thuringiensis were highly resistant against two Lepidopteran species under
           field conditions
    • Authors: Dengxia Yi; Weijie Yang, Jun Tang, Li Wang, Zhiyuan Fang, Yumei Liu, Mu Zhuang, Yangyong Zhang, Limei Yang
      Abstract: Background Plutella xylostella (Linnaeus) has become the most destructive pests in cabbage throughout the world. Cry1Ia8 cabbage has been developed to reduce the pests attacks. To better understand the efficacy of Cry1Ia8 cabbage, a homozygous Cry1Ia8 cabbage line A14‐5 was produced, and its resistance to P. xylostella, Pieris rapae (Linnaeus), and other lepidopteran pests was evaluated in the field in 2011, 2012, and 2013. Results Under natural infestation conditions, the homozygous transgenic line was highly resistant against the P. xylostella and P. rapae as compared to the untransformed control and susceptible to Mamestra brassicae (Linnaeus) and Spodoptera exigua (Hübner). The homozygous transgenic plants showed slight symptoms of damaged leaves by lepidopteran species, while the untransformed plants exhibited serious damage symptoms throughout the entire cabbage growing season. Conclusion Compared with the control, the homozygous transgenic cabbage line showed great potential for protecting cabbage from attack by P. xylostella and P. rapae in the field.
      PubDate: 2015-02-27T00:29:02.885298-05:
      DOI: 10.1002/ps.3994
       
  • Basic Substances: an opportunity for approval of low concern substances
           under EU pesticide regulation
    • Authors: Patrice A. Marchand
      Abstract: Background Plant extracts and by‐products furnish various alternative products for crop protection and are traditionally used by farmers. But the cost and timeframe for their registration as active substances are prohibitive for small companies and farmers’ associations with the new Plant Protection Products (PPP) Regulation (EC) No 1107/2009. However, there is now a possibility to register light compounds as “Basic Substances”, a new category described in article 23 and in the “whereas/ recital (18)”. Results We developed a regulatory expertise on the approval of such products in the framework of the PPP regulation. A Draft Assessment Report in one volume was established, later transformed by EC Directorate into a Basic Substance Application Template, and subsequently used by the EC as a matrix for the corresponding Guidelines for applicants (SANCO 10363/2012 rev. 9). Here we provide further tools, consisting in methodological, linguistic and strategic recommendations in order to constitute a Basic Substance Application (BSA) and proceed to its registration. Conclusion While the use of alternative agents for crop protection is increasing both in organic and conventional agriculture, these usages are still considered as “minor uses”. Our approach and tools are valuable to non‐PPP specialized applicants for simplifying and facilitating their submission of the BSA.
      PubDate: 2015-02-26T02:27:53.033168-05:
      DOI: 10.1002/ps.3997
       
  • Potential and actual uses of zeolites in crop protection
    • Authors: Caroline De Smedt; Edward Someus, Pieter Spanoghe
      Abstract: In this review, it is illustrated that zeolites have a potential to be used as crop protection agents. Similar to kaolin, zeolites can be applied as particle films against pests and diseases. Their honeycomb framework, together with their carbon dioxide sorption capacity and their heat stress reduction capacity, make them suitable as a leaf coating product. Furthermore, their water sorption capacity and their smaller particle sizes make them effective against fungal diseases and insect pests. Finally, these properties also ensure that zeolites can act as carriers of different active substances, which makes it possible to use zeolites for slow‐release applications. Based on literature, a general overview is provided of the different basic properties of zeolites as promising products in crop protection.
      PubDate: 2015-02-26T02:27:18.68575-05:0
      DOI: 10.1002/ps.3999
       
  • Increased frequency and changed methods in the treatment of sea lice
           (Lepeophtherius salmonis) in Scottish salmon farms 2005‐2011
    • Authors: Alexander G Murray
      Abstract: BACKGROUND Sea lice are the most economically and environmentally serious ectoparasite of marine salmonids. Sea lice have been largely controlled by treating with a variety of medicines. In order to understand sustainability of medicine usage an analysis of sea lice treatment data has been carried out for all Scottish salmon farms from 2005 to 2011. RESULTS Overall, there was an increase from 0.156 to 0.282 treatments month‐1; treatments could involve one or multiple agents. This increase was mostly in bath treatments (cypermethrin in 2007 largely replaced by deltamethrin and azamethiphos in 2008). Treatments using in‐feed treatments (emamectin benzoate and teflubenzuron) increased only slowly. Treatments involving more than one medicine in a single month also increased, as did the probability of follow‐up treatments. Treatments were seasonal with peaks of in‐feed treatments in March and August and bath treatments more frequent between August and December. CONCLUSION Frequency of sea lice treatment increased substantially, with an increase in multi‐agent and follow‐up treatments. This increase in treatment activity is expensive to industry and increases exposure of the neighbouring environment. This indicates earlier lice control practices were not sustainable.
      PubDate: 2015-02-24T03:16:59.167878-05:
      DOI: 10.1002/ps.3996
       
  • Widespread occurrence of both metabolic and target‐site herbicide
           resistance mechanisms in Lolium rigidum populations
    • Authors: Heping Han; Qin Yu, Mechelle J Owen, Gregory R Cawthray, Stephen B Powles
      Abstract: Background Lolium rigidum populations in Australia and globally have demonstrated rapid and widespread evolution of resistance to acetyl coenzyme A carboxylase (ACCase)‐ and acetolactate synthase (ALS)‐inhibiting herbicides. Thirty‐three resistant L. rigidum populations, randomly collected from crop fields in a most recent resistance survey, were analysed for non‐target‐site diclofop metabolism and all known target‐site ACCase gene resistance‐endowing mutations. Results The HPLC profile of [14C]‐diclofop‐methyl in vivo metabolism revealed that 79% of these resistant L. rigidum populations showed enhanced capacity for diclofop acid metabolism (metabolic resistance). ACCase gene sequencing identified that 91% of the populations contains plants with ACCase resistance mutation(s). Importantly, 70% of the populations exhibit both non‐target‐site metabolic resistance and target‐site ACCase mutations. Conclusions This work demonstrates that metabolic herbicide resistance is commonly occurring in L. rigidum and co‐evolution of both metabolic resistance and target‐site resistance is an evolutionary reality. Metabolic herbicide resistance can potentially endow resistance to many herbicides and poses a threat to herbicide sustainability and thus crop production, calling for major research and management efforts.
      PubDate: 2015-02-23T02:15:26.391989-05:
      DOI: 10.1002/ps.3995
       
  • Study on long‐distance migration of small brown planthoppers
           Laodelphax striatellus in China using next‐generation
           sequencing
    • Authors: Wenjing Zheng; Zhiqiang Li, Jiaming Zhao, Yanzhi Zhang, Changhua Wang, Xiaochun Lu, Fuyu Sun
      Abstract: Background The small brown planthopper (L. striatellus) is a wide‐spread insect pest of rice in East Asia. Previous studies have shown the long‐distance migrations undertaken by L. striatellus, but did not provide molecular evidence to support this. Results Long‐distance immigration occurred in the northeast coastal rice growing region of China. Using the SALF‐seq technique, sequence data for 2.7Gb of an abruptly increased population and 13 L. striatellus local populations from a range of regions in China that have serious rice stripe disease were obtained. A total of 2572 SNPs and 37 Indels were detected and the genotypes of many polymorphism sites were heterozygous in every sample, which indicated that there were rich genetic differences among the populations and the migration of insect pests accelerated the gene flow and increased the heterozygosity of L. striatellus populations. The genetic distance and the polymorphism markers among different populations showed that the abruptly increased population in Liaoning Province is close to several populations that from Jiangsu Province and Shandong Province. Conclusion The vector that caused rice stripe disease in the northeast of China was an immigrant population; however the population may be formed from several groups from different areas, such as Jiangsu and Shandong Provinces.
      PubDate: 2015-02-13T03:32:00.898739-05:
      DOI: 10.1002/ps.3992
       
  • Fumigation efficacy and emission reduction using low permeability film in
           orchard soil fumigation
    • Authors: Suduan Gao; Lynn M Sosnoskie, J Alfonso Cabrera, Ruijun Qin, Bradley D Hanson, James Gerik, Dong Wang, Greg T Browne, John E Thomas
      Abstract: Background Many orchards use fumigation to control soil borne pests prior to replanting. Controlling emissions is mandatory to reduce air pollution in California, USA. This research evaluated the effects of plastic film type [polyethylene (PE) or totally impermeable film (TIF)], application rate of Telone C35 [full (610 kg/ha), 2/3, or 1/3 rates], and carbonation at 207 kPa on fumigant transport (emission and in soil) and efficacy. Results While increasing fumigant concentrations under the tarp, TIF reduced emissions >95% (~2% and
      PubDate: 2015-02-13T03:31:59.797948-05:
      DOI: 10.1002/ps.3993
       
  • Lack of fitness costs and inheritance of resistance to Bacillus
           thuringiensis Cry1Ac toxin in a near‐isogenic strain of Plutella
           xylostella (Lepidoptera:Plutellidae)
    • Authors: Xun Zhu; Yanjv Yang, Qingjun Wu, Shaoli Wang, Wen Xie, Zhaojiang Guo, Shi Kang, Jixing Xia, Youjun Zhang
      Abstract: BACKGROUND Resistance to Bt formulations in insects may be associated with fitness costs. A lack of cost enable resistance alleles to persist, which may contribute to the rapid develop and spread of resistance in populations. RESULTS To assess the fitness costs associated with Bt Cry1Ac resistance in Plutella xylostella, life tables were constructed for near‐isogenic resistant strain (NIL‐R) and susceptible strain in this study. No fitness costs associated with Cry1Ac resistance in NIL‐R were detected based on duration of egg and larval stages, survival of eggs and larvae, adult longevity, fecundity, net reproductive rate, gross reproduction rate, finite rate of increase, or mean generation time. Based on log dose–probit lines, resistance in NIL‐R is incompletely recessive and results from a single, autosomal, recessive locus; the degree of dominance was estimated to be −0.74 and −0.71 for F1 (resistant ♀ × susceptible ♂) and F1’ (susceptible ♀ × resistant ♂) progeny, respectively. CONCLUSION Assessment of near‐isogenic Cry1Ac‐resistant and ‐susceptible strains of P. xylostella indicated that resistance is not accompanied by fitness costs and that resistance is incompletely recessive. These finding should be useful for managing the development of Bt Cry1Ac resistance.
      PubDate: 2015-02-12T03:30:33.803156-05:
      DOI: 10.1002/ps.3991
       
  • Establishment of an RTA‐Bddsx hybrid system for
           female‐specific splicing that can affect the sex ratio of Bactrocera
           dorsalis (Hendel) after embryonic injection
    • Authors: Chun‐Yen Huang; Chia Chia Huang, Shu‐Mei Dai, Cheng Chang
      Abstract: Background The oriental fruit fly, Bactrocera dorsalis (Hendel), a very destructive insect pest in many areas of Asia, including Taiwan, can cause significant damages by ovipositing in and larval feeding of many kinds of fruits. A female lethal system, combining the splicing property of doublesex (dsx) with the toxicity of ricin A chain (RTA), has been developed. In this system, a modified RTA is separated by Bddsx intron 3; the expressed RNA can only be spliced in females, with toxic effects, whereas the immature RTA in males is harmless. Results Two RTA‐Bddsx constructs, clone BE 24–7 and clone CF 26–21, containing Bddsx intron 3 and its flanking exonic sequences, with 4 nucleotides at 5’ end and 5 nucleotides at 3’ end, correctly spliced in a sex‐specific manner. Wild‐type and modified RTAs expressed in E. coli system retained their ability to suppress protein synthesis: 90.4% for Ricin‐WT, 71.3% for Ricin‐LERQ, and 58.0% for Ricin‐FEGQ. Embryonic injection of Acp‐CF26‐21, the RTA‐Bddsx gene driven by the actin 5C promoter, resulted in a significant increase of male percentage in the eclosed adults. Conclusion Our results indicate the RTA‐Bddsx hybrid system offers a novel and promising approach for oriental fruit fly control.
      PubDate: 2015-02-05T05:17:18.090763-05:
      DOI: 10.1002/ps.3990
       
  • Naturally occurring bioactive compounds from four repellent essential oils
           against Bemisia tabaci whiteflies
    • Authors: Emilie Deletre; Fabrice Chandre, Barbara Barkman, Chantal Menut, Thibaud Martin
      Abstract: Background In tropical countries, netting is an effective sustainable tool for protecting horticultural crops against Lepidoptera, though not against small pests like Bemisia tabaci, while smaller mesh netting can be used in temperate regions. A solution is to combine a net with a repellent. Previously we identified repellent essential oils: lemongrass (Cymbopogon citratus), cinnamon (Cinnamomum zeylanicum), cumin (Cuminum cyminum) and citronella (Cymbopogon winternarius). The present study was designed to identify the active compounds of these essential oils, characterize their biological activity, and examine their potential for coating nets. We investigated the efficiency and toxicity of nets dipped in different solutions. We then studied the repellent effect with an olfactometer and the irritant effect by videotracking. Results Geraniol and citronellol were the most promising net coatings due to their repellent effect. The repellency, irritancy or toxicity varied with the product and concentration and these features were independent, indicating that the repellent and the irritant/toxic mechanisms were not the same. The combined effects of these different compounds account for the bioactivity of the mixture, suggesting interactions between the compounds. Conclusion This new sustainable strategy for protecting vegetable crops against whiteflies is discussed, in addition to the use of companion plants that could produce such bioactive compounds.
      PubDate: 2015-02-02T02:10:58.748534-05:
      DOI: 10.1002/ps.3987
       
  • Understanding trophic interactions of Orius spp. (Hemiptera: Anthocoridae)
           in lettuce crops by molecular methods
    • Authors: Priscila Gomez‐Polo; Oscar Alomar, Cristina Castañé, Thaïs Aznar‐Fernández, Jonathan G Lundgren, Josep Piñol, u Agustí
      Abstract: Background The aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) and the thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) are common pests in Mediterranean lettuce crops, where Orius spp. are common generalist predators. Predation by Orius spp. was studied in a lettuce plot by conventional PCR and real‐time PCR analyses using specific primers of both main pests. Also high‐throughput sequencing was used to have a wider approach of the diet of these predators in natural field conditions. Results Molecular analyses indicated a higher predation on N. ribisnigri in spring and on F. occidentalis in summer. Predation on alternative prey, like Collembola, was also found in both seasons. Real‐time PCR was more sensitive than conventional PCR in showing the target trophic links, whereas high‐throughput sequencing revealed predation on other natural enemies (Intraguild Predation (IGP)), showing other trophic interactions of Orius majusculus within the studied ecosystem. Conclusions This study gives important information about the trophic relationships present in Mediterranean lettuce crops in different periods of the year. The detected predation by Orius spp. on alternative prey, as well as on other natural enemies should be further investigated to clarify whether it adds or detracts to the biological control of N. ribisnigri and F. occidentalis.
      PubDate: 2015-01-31T04:31:15.207861-05:
      DOI: 10.1002/ps.3989
       
  • Should I fight or should I flight? How studying insect aggression can
           help Integrated Pest Management
    • Authors: Giovanni Benelli
      Abstract: Aggression plays a key role all across the Animal Kingdom, as it allows the acquisition and/or defence of limited resources (food, mates and territories) in a huge number of species. A large part of our knowledge on aggressive behaviour has been developed on insects of economic importance. How can this knowledge be exploited to enhance Integrated Pest Management? Here, I highlight how knowledge on intra‐specific aggression can help IPM both in terms of insect pests (with a focus on the enhancement of the Sterile Insect Technique), and biological control agents (with a focus on mass‐rearing optimisation). Then, I examine what implications for IPM can be outlined from knowledge about inter‐specific aggressive behaviour. Besides predator‐pest aggressive interactions predicted by classic biological control, I focus on what IPM can learn from (i) inter‐specific aggression among pest species (with special reference to competitive displacement), (ii) defensive behaviour exhibited by prey against predaceous insects, and (iii) conflicts among predaceous arthropods sharing the same trophic niche (with special reference to learning/sensitisation practices and artificial manipulation of chemically‐mediated interactions).
      PubDate: 2015-01-13T01:45:59.855255-05:
      DOI: 10.1002/ps.3974
       
 
 
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