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  Subjects -> ENGINEERING (Total: 1955 journals)
    - CHEMICAL ENGINEERING (153 journals)
    - CIVIL ENGINEERING (148 journals)
    - ELECTRICAL ENGINEERING (81 journals)
    - ENGINEERING (1113 journals)
    - ENGINEERING MECHANICS AND MATERIALS (289 journals)
    - HYDRAULIC ENGINEERING (45 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (74 journals)

ENGINEERING (1113 journals)            First | 4 5 6 7 8 9 10 11 | Last

Journal of Networks     Open Access   (Followers: 3)
Journal of Nonlinear Dynamics     Open Access  
Journal of Oceanography and Marine Science     Open Access   (Followers: 2)
Journal of Operations Management     Hybrid Journal   (Followers: 13)
Journal of Optics     Hybrid Journal   (Followers: 2)
Journal of Organizational Behavior     Hybrid Journal   (Followers: 20)
Journal of Petroleum Science Research     Open Access   (Followers: 1)
Journal of Phase Equilibria and Diffusion     Hybrid Journal  
Journal of Power Sources     Partially Free   (Followers: 22)
Journal of Pre-College Engineering Education Research     Open Access  
Journal of Pressure Vessel Technology     Full-text available via subscription   (Followers: 9)
Journal of Professional Issues in Engineering Education and Practice     Full-text available via subscription   (Followers: 6)
Journal of Quality and Reliability Engineering     Open Access  
Journal of Quality in Maintenance Engineering     Hybrid Journal   (Followers: 3)
Journal of Radiation Research and Applied Sciences     Open Access   (Followers: 1)
Journal of Rare Earths     Full-text available via subscription   (Followers: 2)
Journal of Real-Time Image Processing     Hybrid Journal   (Followers: 5)
Journal of Regional Science     Hybrid Journal   (Followers: 6)
Journal of Reinforced Plastics and Composites     Hybrid Journal   (Followers: 4)
Journal of Research of NIST     Open Access   (Followers: 1)
Journal of Rock Mechanics and Geotechnical Engineering     Open Access   (Followers: 2)
Journal of Russian Laser Research     Hybrid Journal  
Journal of Safety Engineering     Open Access   (Followers: 3)
Journal of Safety Research     Hybrid Journal   (Followers: 4)
Journal of Science and Technology     Open Access  
Journal of Science and Technology (Ghana)     Open Access   (Followers: 1)
Journal of Science and Technology Policy Management     Hybrid Journal   (Followers: 3)
Journal of Scientific Computing     Hybrid Journal   (Followers: 2)
Journal of Scientific Innovations for Development     Open Access   (Followers: 2)
Journal of Semiconductors     Full-text available via subscription   (Followers: 2)
Journal of Sensor Technology     Open Access   (Followers: 2)
Journal of Shanghai Jiaotong University (Science)     Hybrid Journal  
Journal of Sol-Gel Science and Technology     Hybrid Journal   (Followers: 2)
Journal of Solar Energy     Open Access   (Followers: 2)
Journal of Solar Energy Engineering     Full-text available via subscription   (Followers: 14)
Journal of Superconductivity and Novel Magnetism     Partially Free   (Followers: 1)
Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques     Hybrid Journal   (Followers: 1)
Journal of Surveying Engineering     Full-text available via subscription   (Followers: 7)
Journal of Technology Management & Innovation     Open Access   (Followers: 2)
Journal of Telecommunications Management     Full-text available via subscription   (Followers: 2)
Journal of Testing and Evaluation     Full-text available via subscription   (Followers: 9)
Journal of the Air & Waste Management Association     Hybrid Journal   (Followers: 3)
Journal of the Chinese Institute of Engineers     Hybrid Journal  
Journal of the Chinese Institute of Industrial Engineers     Hybrid Journal   (Followers: 1)
Journal of the Franklin Institute     Full-text available via subscription   (Followers: 2)
Journal of the Institution of Engineers (India ): Series D     Hybrid Journal  
Journal of the Institution of Engineers (India) : Series B     Hybrid Journal   (Followers: 1)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal  
Journal of the Institution of Engineers (India): Series A     Hybrid Journal  
Journal of the Institution of Engineers (India): Series C     Hybrid Journal   (Followers: 1)
Journal of the National Science Foundation of Sri Lanka     Open Access   (Followers: 1)
Journal of the University of Ruhuna     Open Access  
Journal of Thermal Science and Engineering Applications     Full-text available via subscription   (Followers: 2)
Journal of Thermal Stresses     Hybrid Journal   (Followers: 3)
Journal of Transplantation     Open Access   (Followers: 3)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 5)
Journal of Transportation Engineering     Full-text available via subscription   (Followers: 13)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 12)
Journal of Tribology     Full-text available via subscription   (Followers: 8)
Journal of Turbomachinery     Full-text available via subscription   (Followers: 6)
Journal of Turbulence     Hybrid Journal  
Journal of Unmanned Vehicle Systems     Full-text available via subscription   (Followers: 1)
Journal of Urban and Environmental Engineering     Open Access  
Journal of Urban Planning and Development     Full-text available via subscription   (Followers: 27)
Journal of Urban Regeneration and Renewal     Full-text available via subscription   (Followers: 10)
Journal of Vibration and Acoustics     Full-text available via subscription   (Followers: 19)
Journal of Visualization     Hybrid Journal   (Followers: 2)
Journal of Volcanology and Seismology     Hybrid Journal   (Followers: 1)
Journal of Wuhan University of Technology-Mater. Sci. Ed.     Hybrid Journal  
Journal of X-Ray Science and Technology     Hybrid Journal  
Journal of Zhejiang University SCIENCE A     Hybrid Journal  
Journal on Chain and Network Science     Full-text available via subscription   (Followers: 2)
Jurnal Teknologi     Open Access   (Followers: 1)
Karaelmas Science and Engineering Journal     Open Access  
Kleio     Full-text available via subscription   (Followers: 2)
Landscape and Ecological Engineering     Hybrid Journal   (Followers: 3)
Langmuir     Full-text available via subscription   (Followers: 35)
Leadership and Management in Engineering     Full-text available via subscription   (Followers: 9)
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Lighting Research and Technology     Hybrid Journal  
Logic and Analysis     Hybrid Journal  
Logica Universalis     Hybrid Journal  
Lubrication Science     Hybrid Journal  
Machines     Open Access  
Machining Science and Technology: An International Journal     Hybrid Journal   (Followers: 2)
Macromolecular Reaction Engineering     Hybrid Journal  
Magazine of Concrete Research     Hybrid Journal   (Followers: 4)
Magdeburger Journal zur Sicherheitsforschung     Open Access  
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 1)
Management and Production Engineering Review     Open Access  
Management Science and Engineering     Open Access   (Followers: 1)
Manufacturing Engineer     Hybrid Journal   (Followers: 4)
Manufacturing Research and Technology     Full-text available via subscription   (Followers: 5)
MATEC Web of Conferences     Open Access  
Matériaux & Techniques     Full-text available via subscription   (Followers: 1)
Mathematical Models and Methods in Applied Sciences     Hybrid Journal   (Followers: 2)
Mathematical Problems in Engineering     Open Access   (Followers: 3)
Mathematics of Control, Signals, and Systems (MCSS)     Hybrid Journal   (Followers: 4)
Mauerwerk     Hybrid Journal  
Measurement     Hybrid Journal   (Followers: 1)

  First | 4 5 6 7 8 9 10 11 | Last

Journal Cover Pest Management Science
   [6 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1526-498X - ISSN (Online) 1526-4998
     Published by John Wiley and Sons Homepage  [1603 journals]   [SJR: 0.99]   [H-I: 64]
  • Identification and characterization of multiple glutathione
           S‐transferase genes from the diamondback moth, Plutella xylostella
    • Authors: Xi'en Chen; Ya‐lin Zhang
      Pages: n/a - n/a
      Abstract: Background The diamondback moth (DBM), Plutella xylostella, is one of the most harmful insect pests on crucifer crops worldwide. In this study, 19 cDNA encoding glutathione S‐transferases (GSTs) were identified from the genomic and transcriptomic database for DBM (KONAGAbase) and further characterized. Results Phylogenetic analysis showed that 19 GSTs were classified into six different cytosolic classes, including 4 in delta, 6 in epsilon, 3 in omega, 2 in sigma, 1 in theta, and 1 in zeta. Two GSTs were unclassified. RT‐PCR analysis revealed most GSTs genes were expressed in all developmental stages with relatively higher expression in the larval stages. Six DBM GSTs were expressed at the highest levels in the midgut tissue. Twelve purified recombinant GSTs showed varied enzymatic properties toward CDNB and GSH, whereas rPxGSTo2, rPxGSTz1, and rPxGSTu2 had no activity. Real‐time quantitative PCR revealed that expression levels of 19 DBM GSTs genes were varied and changed after exposure to acephate, indoxacarb, beta‐cypermethrin, and spinosad. PxGSTd3 was significantly overexpressed while PxGSTe3 and PxGSTs2 were significantly down‐regulated by all four insecticide exposures. Conclusion The changes in DBM GSTs gene expression levels exposed to different insecticides indicate they may play individual roles in tolerance to insecticides and xenobiotics.
      PubDate: 2014-08-15T05:59:24.465718-05:
      DOI: 10.1002/ps.3884
       
  • Dealing with transgene flow of crop protection traits from crops to their
           relatives
    • Authors: Jonathan Gressel
      Pages: n/a - n/a
      Abstract: Genes regularly move within species, to/from crops, as well as to their con‐ specific progenitors, feral and weedy forms (‘vertical’ gene flow). Genes occasionally move to/from crops and their distantly related, hardly sexually interbreeding relatives, within a genus or among closely related genera (diagonal gene flow). Regulators have singled out transgene flow as an issue, yet non‐transgenic herbicide resistance traits pose equal problems, which cannot be mitigated. The risks are quite different from genes flowing to natural (wild) ecosystems versus ruderal and agroecosystems. Transgenic herbicide resistance poses a major risk if introgressed into weedy relatives; disease and insect resistance less so. Technologies have been proposed to contain genes within crops (chloroplast transformation, male sterility) that imperfectly prevent gene flow by pollen to the wild. Containment does not prevent related weeds from pollinating crops. Repeated backcrossing with weeds as pollen parents results in gene establishment in the weeds. Transgenic mitigation relies on coupling crop protection traits in a tandem construct with traits that lower the fitness of the related weeds. Mitigation traits can be morphological (dwarfing, no seed shatter) or chemical (sensitivity to a chemical used later in a rotation). Tandem mitigation traits are genetically linked and will move together. Mitigation traits can also be spread by inserting them in multicopy transposons which disperse faster than the crop protection genes in related weeds. Thus, there are gene flow risks mainly to weeds from some crop protection traits; risks that can and should be dealt with. © 2014 Society of Chemical Industry
      PubDate: 2014-08-15T05:36:04.894193-05:
      DOI: 10.1002/ps.3850
       
  • Resmethrin, the First Modern Pyrethroid Insecticide
    • Authors: David M. Soderlund
      Pages: n/a - n/a
      Abstract: The discovery of resmethrin almost five decades ago was the seminal event in the development of pyrethroid insecticides as important pest management tools whose value endures today. This brief review considers the development of pyrethroids from the perspective of the discovery of resmethrin. I describe the pathway to the discovery of resmethrin and the unique properties that differentiated it from the pyrethrins and earlier synthetic pyrethroids. I also summarize information on metabolic fate and mechanisms of selective toxicity, first elucidated with resmethrin, that have shaped our understanding of pyrethroid toxicology since that time. Finally, I review the discovery pathway that led from resmethrin to the development of the first photostable, agriculturally useful pyrethroids that established the importance of this insecticide class.
      PubDate: 2014-08-14T03:20:37.824077-05:
      DOI: 10.1002/ps.3881
       
  • Identification of putative kdr mutations in the tropical bed bug, Cimex
           hemipterus (Hemiptera: Cimicidae).
    • Authors: Kai Dang; Cheryl S. Toi, David G. Lilly, Chow‐Yang Lee, Richard Naylor, Apiwat Tawatsin, Usavadee Thavara, Wenun Bu, Stephen L. Doggett
      Pages: n/a - n/a
      Abstract: Background Bed bugs (both Cimex hemipterus [F.] and Cimex lectularius L.) worldwide are highly resistant to the pyrethroids. An important resistance mechanism known as ‘knockdown resistance’ (kdr) is caused by genetic point mutations on the voltage‐gated sodium channel (VGSC) gene. Previous studies have identified two point mutations (V419L and L925I) on the VGSC gene in C. lectularius that are responsible for kdr‐type resistance. However, the kdr mutations in C. hemipterus have not been investigated. Results Four novel mutations, L899V (leucine to valine), M918I (methionine to isoleucine), D953G (aspartic acid to glycine) and L1014F (leucine to phenylalanine), were identified in the domain II region of the C. hemipterus VGSC gene. This region has been widely investigated for the study of ‘kdr’‐type resistance to the pyrethroids in other insect pests. The V419L and L925I kdr mutations as previously identified in C. lectularius, were not detected in C. hemipterus. Conclusion M918I and L1014F were considered probable kdr mutations and may play essential roles in kdr‐type resistance to pyrethroids in C. hemipterus. Further studies are in process to determinate the non‐kdr type resistance mechanisms in C. hemipterus in our laboratory.
      PubDate: 2014-08-14T03:20:35.818616-05:
      DOI: 10.1002/ps.3880
       
  • Concerted action of target‐site mutations and high EPSPS activity in
           glyphosate‐resistant junglerice (Echinochloa colona) from California
           
    • Authors: Rocío Alarcón‐Reverte; Alejandro García, Susan B. Watson, Ibrahim Abdallah, Sebastián Sabaté, María J. Hernández, Franck E. Dayan, Albert Fischer
      Pages: n/a - n/a
      Abstract: Background Echinochloa colona is an annual weed affecting field crops and orchards in California. An E. colona population carrying a mutation in the EPSPS gene endowing resistance to glyphosate, the most widely used non‐selective herbicide, was recently identified in the Northern Sacramento Valley of California. Plants from this population, from a suspected glyphosate‐resistant (GR) population, and from one susceptible (S) population collected in the Northern Sacramento Valley of California were used to generate three GR and one S selfed lines to study possible mechanisms involved in glyphosate resistance. Results Based on the amount of glyphosate required to kill 50% of the plants (LD50), GR lines were 4‐ to 9‐fold more resistant than S plants and accumulated less shikimate after glyphosate treatment. GR and S lines did not differ in glyphosate absorption, translocation or metabolism. A different target site mutation was found in each of two of the GR lines corresponding to Pro106Thr and Pro106Ser substitutions; the mutations were found in different homoeologous EPSPS genes. No mutation was found in the third GR line, which exhibited 1.4‐fold higher basal EPSPS activity and a 5‐fold greater LD50 than S plants. Quantitative RT‐PCR revealed that GR lines had similar or lower EPSPS expression than S plants. Conclusion We demonstrate that individuals with different glyphosate resistance mechanisms can coexist in the same population, individuals from different populations may carry different resistance mechanisms, and different mechanisms can act in concert within single E. colona plants. However, other plant factors or resistance mechanisms appear to modulate plant expression of EPSPS sensitivity to glyphosate.
      PubDate: 2014-08-13T01:06:41.453335-05:
      DOI: 10.1002/ps.3878
       
  • Transportation Behavior of fluopicolide and its control effect against
           Phytophthora capsici in greenhouse tomatoes after soil application
    • Authors: Lili Jiang; Hongyan Wang, Hui Xu, Kang Qiao, Xiaoming Xia, Kaiyun Wang
      Pages: n/a - n/a
      Abstract: Background Fluopicolide, a novel benzamide fungicide, was registered for control of oomycete pathogens, of which P. capsici is included. In this study, fluopicolide (5% SC) was applied in soil at the rate of 1.5, 3 and 6 L ha−1 (which is normal, double and quadruple dosage respectively) to investigate its transportation behavior and control efficiency on tomato blight as a soil treatment agent. Results The results showed that, soil treated fluopicolide could be absorbed by tomato roots and then transplanted to stems and leaves. It could exist in tomato roots for more than 30 days, and in leaves and stems until the 20th day. The decline discipline of fluopicolide in soil was in accordance with the first order dynamic equation, with half‐lives (t1/2) 5.33, 4.75 and 5.42 d for the ND, DD and QD treatment respectively. The control efficiencies of soil treated fluopicolide were better than spraying applied one, and the inhibition ratios were 93.02%, 97.67% and 100% on the 21st day for the ND, DD and QD treatment respectively. Conclusion Soil application of fluopicolide could control P. capsici in greenhouse tomatoes with high efficiency and long persistence.
      PubDate: 2014-08-12T03:42:54.52326-05:0
      DOI: 10.1002/ps.3879
       
  • Data worth and prediction uncertainty for pesticide transport and fate
           models in Nebraska and Maryland, USA
    • Authors: Bernard T Nolan; Robert W Malone, John E Doherty, Jack E Barbash, Liwang Ma, Dale L Shaner
      Pages: n/a - n/a
      Abstract: Background Complex environmental models frequently are extrapolated to overcome data limitations in space and time, but quantifying data worth to such models is rarely attempted. We determined which field observations most informed the parameters of agricultural systems models applied to field sites in Nebraska (NE) and Maryland (MD), and we identified parameters and observations that most influenced prediction uncertainty. Results The standard error of regression of the calibrated models was about the same at both NE (0.59) and MD (0.58), and overall reductions in prediction uncertainties of metolachlor and metolachlor ethane sulfonic acid concentrations were 98.0 and 98.6 %, respectively. Observation data groups reduced the prediction uncertainty by 55–90 % at NE and 28–96 % at MD. Soil hydraulic parameters were well informed by the observed data at both sites, but pesticide and macropore properties had comparatively larger contributions after model calibration. Conclusions Although the observed data were sparse, they substantially reduced prediction uncertainty in unsampled regions of pesticide breakthrough curves. Nitrate evidently functioned as a surrogate for soil hydraulic data in well‐drained loam soils conducive to conservative transport of nitrogen. Pesticide properties and macropore parameters could most benefit from improved characterization to further reduce model misfit and prediction uncertainty.
      PubDate: 2014-08-06T07:38:34.263931-05:
      DOI: 10.1002/ps.3875
       
  • Efficacy of thiamethoxam and fipronil, applied alone and in combination,
           to control Limonius californicus and Hypnoidus bicolor (Coleoptera:
           Elateridae)
    • Authors: Anuar Morales‐Rodriguez; Kevin W. Wanner
      Pages: n/a - n/a
      Abstract: Background Wireworms, the larval stage of click beetles (Family Elateridae), are significant soil pests of wheat and barley crops in the Pacific Northwest. At present, few pest management alternatives exist. For several decades, wireworms were effectively controlled by first generation insecticides applied to the soil or as seed treatments. Currently used neonicotinoid insecticides protect crop seeds and germinating seedlings by temporary toxicity but limited mortality. As a result, field populations may increase, reaching levels too high for crop protection. In this study we investigated the combination of two insecticides to achieve crop protection as well as insect mortality in wheat fields. Results Laboratory bioassays using wheat seed treated with fipronil at 1.0 and 5.0 grams AI 100 kg−1 of seed resulted in 72‐90% mortality of two wireworm species, Limonius californicus and Hypnoidus bicolor. At a rate of 39 g AI 100 kg−1 kg of seed, eight times higher than the high rate of fipronil, thiamethoxam caused only 10‐31% larval mortality in the bioassays, but did protect developing wheat stands from damage in field trials. Field plots planted with wheat seed treated with both 5.0 g AI of fipronil and 39.0 g AI of thiamethoxam 100 kg−1 of seed had 83% fewer wireworms the following year compared to untreated check plots. No reduction in population was observed in plots treated with 39.0 g of thiamethoxam alone. Conclusions Fipronil and thiamethoxam can be combined as a seed treatment to protect wheat crops from wireworm damage and reduce larval populations in the field.
      PubDate: 2014-08-06T07:37:19.940157-05:
      DOI: 10.1002/ps.3877
       
  • Establishment of multiple pesticide biodegradation capacities from
           pesticide‐primed materials in on‐farm biopurification system
           microcosms treating complex pesticide‐contaminated waste water
    • Authors: Kristel Sniegowski; Dirk Springael
      Pages: n/a - n/a
      Abstract: Background “On farm” biopurification systems (BPS) treat pesticide containing waste water at farms by biodegradation and sorption processes. The inclusion of pesticide‐primed material carrying a pesticide degrading microbial community is beneficial to improve biodegradation but no data exist for treating wastewater containing multiple pesticides as often occurs at farms. In a microcosm setup, it was examined whether multiple pesticides degradation activities could be simultaneously established in the matrix of a BPS, by simultaneous inclusion of different appropriate pesticide‐primed materials. The microcosms were fed with a mixture of pesticides including the fungicide metalaxyl and the herbicides bentazon, isoproturon, linuron and metamitron and pesticide degrading activities were monitored in time. Results The strategy immediately provided the microcosms with a multiple pesticide degradation/mineralization capacity that improved during feeding of the pesticide mixture. Not only the degradation of the parent compound improved but also this of produced metabolites and compound mineralization. The time to achieve maximum degradation/mineralization capacity depended on the pesticide degradation capacity of the pesticide primed materials. Conclusions Our data show that the addition of pesticide‐primed materials into the matrix of a BPS as an approach to improve biodegradation, can be extended towards the treatment of pesticide mixtures.
      PubDate: 2014-08-05T02:10:35.462975-05:
      DOI: 10.1002/ps.3876
       
  • Intensive cropping systems select for greater seed dormancy and increased
           herbicide resistance levels in Lolium rigidum (annual ryegrass)
    • Authors: Mechelle J. Owen; Danica E. Goggin, Stephen B. Powles
      Pages: n/a - n/a
      Abstract: Background Lolium rigidum (annual ryegrass) is a widespread annual crop weed which has evolved high levels of resistance to selective herbicides. Anecdotal evidence suggests that intensive cropping also leads to higher seed dormancy in L. rigidum. This was quantified by measuring dormancy levels in L. rigidum populations collected from paired sites (one with nil to low cropping intensity, the other intensively cropped) located throughout the Western Australian grain belt. Results Populations from non‐cropped fields or those with low cropping intensity showed higher and faster germination than populations from fields with a medium‐ or high‐intensity cropping regime. Resistance to selective herbicides was also higher in the medium‐ and high‐intensity cropping fields than in the low‐intensity cropping fields. Conclusion High‐intensity cropping systems are likely to impose greater selection pressures for seed dormancy and selective herbicide resistance, because late‐emerging seedlings avoid pre‐planting weed control practices (tillage and non‐selective herbicide application) but are exposed to selective in‐crop herbicides.
      PubDate: 2014-08-01T04:05:22.303242-05:
      DOI: 10.1002/ps.3874
       
  • Mating competitiveness and life table comparisons between transgenic and
           Indian wild type Aedes aegypti L.
    • Authors: Prabhakargouda B Patil; Niranjan B P Reddy, Kevin Gorman, Seshu Reddy V K, Shirish R Barwale, Usha B Zehr, Derric Nimmo, Neil Naish, Luke Alphey
      Pages: n/a - n/a
      Abstract: Background OX513A is a genetically‐engineered strain of Ae. aegypti carrying a repressible, dominant inherited transgene that confers lethality in immature heterozygous progeny. Released male OX513A adults have proven effective for the localised suppression of wild Ae. aegypti, highlighting its potential in vector control. Mating and life table assessments were used to compare OX513A with reared Ae. aegypti strains collected from New Delhi and Aurangabad regions in India. Results Mating proportions of New Delhi females versus males of OX513A or New Delhi strains were 0.52 and 0.48 respectively, indicating no discrimination by females against either strain, and males of both strains were equally competitive. Developmental time from first instar to adult emergence was significantly longer for OX513A (10.7 ± 0.04 days) than for New Delhi (9.4 ± 0.04 days) and Aurangabad strains (9.1 ± 0.04 days). Differences in mean longevities, female reproductive parameters and population growth parameters between the strains were non‐significant. Conclusions Present laboratory study demonstrates that, only minor life table variations of limited biological relevance exist between OX513A and Indian Ae. aegypti populations, and males were equally potential for mating competitiveness. Thus results support OX513A strain as a suitable candidate for continued evaluation towards sustainable management of Ae. aegypti populations in India.
      PubDate: 2014-07-31T03:54:20.897985-05:
      DOI: 10.1002/ps.3873
       
  • Effect of insecticidal fusion proteins containing spider toxins targeting
           sodium and calcium ion channels on pyrethroid‐resistant strains of
           peach‐potato aphid (Myzus persicae)
    • Authors: Sheng Yang; Elaine Fitches, Prashant Pyati, John A. Gatehouse
      Pages: n/a - n/a
      Abstract: Background The recombinant fusion proteins Pl1a/GNA and Hv1a/GNA contain the spider venom peptides δ‐amaurobitoxin‐PI1a or ω‐hexatoxin‐Hv1a respectively, linked to snowdrop lectin (GNA). Pl1a targets receptor site 4 of insect voltage‐gated sodium channels (NaCh) while Hv1a targets voltage‐gated calcium channels. Insecticide‐resistant strains of peach‐potato aphid (Myzus persicae) contain mutations in NaCh. The pyrethroid‐resistant "kdr" (794J) and "super‐kdr" (UKO) strains contain mutations at residues L1014 and M918 in the channel α‐subunit respectively, while the "kdr + super‐kdr" strain (4824J), insensitive to pyrethroids, contains mutations at both L1014 and M918. Results Pl1a/GNA and Hv1a/GNA fusion proteins have estimated LC50 values of 0.35 and 0.19 mg ml−1 when fed to wild‐type M. persicae. For insecticide‐resistant aphids, LC50 for the Pl1a/GNA fusion protein increased by 2‐ to 6‐fold, correlating with pyrethroid resistance (wild‐type < kdr < super‐kdr < kdr + super‐kdr strains). In contrast, LC50 for the Hv1a/GNA fusion protein showed limited correlation with pyrethroid resistance. Conclusion Mutations in the sodium channel in pyrethroid‐resistant aphids also protect against a fusion protein containing a sodium channel‐specific toxin, despite differences in ligand‐channel interactions, but do not confer resistance to a fusion protein targeting calcium channels. The use of fusion proteins with differing targets could play a role in managing pesticide resistance.
      PubDate: 2014-07-31T03:45:19.438895-05:
      DOI: 10.1002/ps.3872
       
  • Metabolism of agrochemicals and related environmental chemicals based on
           cytochrome P450s in mammals and plants
    • Authors: Hideo Ohkawa; Hideyuki Inui
      Pages: n/a - n/a
      Abstract: A yeast gene expression system originally established for mammalian cytochrome P450 monooxygenase cDNAs was applied to functional analysis of a number of mammalian and plant P450 species including 11 human P450 species (CYP1A1, CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP2D6, CYP2E1 and CYP3A4). The human P450 species CYP1A1, CYP1A2, CYP2B6, CYP2C18 and CYP2C19 were identified as P450 species metabolizing various agrochemicals and environmental chemicals. CYP2C9 and CYP2E1 specifically metabolized sulfonylurea herbicides and halogenated hydrocarbons, respectively. Plant P450 species metabolizing phenylurea and sulfonylurea herbicides were also identified mainly as CYP71 family, although CYP76B1, CYP81B1 and CYP81B2 metabolized phenylurea herbicides. The transgenic plants expressing these mammalian and plant P450 species were applied to herbicide tolerance as well as phytoremediation of agrochemical and environmental chemical residues. The combined use of CYP1A1, CYP2B6 and CYP2C19 belonging to 2 families and 3 subfamilies covered a wide variety of herbicide tolerance and phytoremediation of these residues. The use of 2,4‐D and bromoxynil induced CYP71AH11 in tobacco seemed to enhance herbicide tolerance and selectivity.
      PubDate: 2014-07-31T02:14:40.571498-05:
      DOI: 10.1002/ps.3871
       
  • Neonicotinoids and bumble bees (Bombus terrestris): Effects on nectar
           consumption in individual workers
    • Authors: Helen M. Thompson; Selwyn Wilkins, Sarah Harkin, Sarah Milner, Keith F A Walters
      Pages: n/a - n/a
      Abstract: Background The objective of this study was to quantify whether the presence of three different neonicotinoid insecticides in sucrose solution: imidacloprid, thiamethoxam or clothianidin results in anti‐feedant effects in individual worker bumble bees (Bombus terrestris) and, if so, whether this effect is reversible if bees are subsequently offered untreated feed. Results Bees exposed to imidacloprid displayed a significant dose‐dependent reduction in consumption at 10 and 100 µg/L which was reversed when untreated feed was offered. No consistent avoidance/antifeedant response to nectar substitute with thiamethoxam was detected at the more field realistic dose rates of 1 and 10 µg/L, and exposure to the very high 100 µg/L dose rate was followed by 100% mortality of experimental insects. At 1 µg clothianidin /L no reduction in food intake was recorded, at 10 µg clothianidin /L reduced consumption was noted and 100% mortality occurred when bees were exposed to rates of 100 µg clothianidin /L. Conclusion This study provides evidence of a direct anti‐feedant effect of imidacloprid and clothianidin in individual bumble bees but highlights that this may be a compound specific effect.
      PubDate: 2014-07-30T03:10:25.857145-05:
      DOI: 10.1002/ps.3868
       
  • Transgenic cry1C or cry2A Rice had no Adverse Impacts on Life‐table
           Parameters and Population Dynamics of the Brown Planthopper, Nilaparvata
           lugens (Hemiptera: Delphacidae)
    • Authors: Zeng‐Bing Lu; Yu‐E Liu, Nai‐Shun Han, Jun‐Ce Tian, Yu‐Fa Peng, Cui Hu, Yu‐Yuan Guo, Gong‐Yin Ye
      Pages: n/a - n/a
      Abstract: Background Transgenic rice producing the insecticidal protein from Bacillus thuringiensis Berliner (Bt) is protected from damage by lepidopteran insect pests. However, one of the main concerns about Bt rice is their potential impacts on non‐target herbivores. In the current study, ecological impacts of two Bt rice lines, T1C‐19 expressing Cry1C protein and T2A‐1 expressing Cry2A protein, on the non‐target herbivore brown planthopper (BPH), Nilaparvata lugens (Stål), were evaluated under laboratory and field conditions. The purpose was to verify whether these Bt rice lines could affect the performance of BPH at individual and population scales. Results Laboratory results showed that most of the fitness parameters (development duration, survival rate, fecundity, fertility, amount of honeydew excreted) of BPH were not significantly affected by two tested Bt rice lines, although the development duration of 4th instar nymphs fed on T1C‐19 was distinctly longer compared with that on T2A‐1 and non‐Bt rice plants. Five life‐table parameters did not significantly differ among rice types. Two‐year field trials also revealed no significant difference in population dynamics of BPH among rice types. Conclusion It is inferred that our tested Bt rice lines will unlikely affect the population growth of BPH as released to farmers in future.
      PubDate: 2014-07-28T05:43:32.536934-05:
      DOI: 10.1002/ps.3866
       
  • Characterization of heteroplasmic status at codon 143 of Botrytis cinerea
           cytochrome b gene using semi‐quantitative AS‐PCR assay
    • Authors: Maki Hashimoto; Yoshinao Aoki, Seiya Saito, Shunji Suzuki
      Pages: n/a - n/a
      Abstract: Background An in‐depth understanding of QoI‐fungicide‐resistant B. cinerea isolates in a vineyard is expected to contribute to the development of an optimum disease management program for the control of grape grey mould. Results We characterized the resistance and structure of cytochrome b gene in B. cinerea collected from a Japanese vineyard. The semi‐quantitative AS‐PCR assay developed in the present study was able to distinguish heteroplasmic status from homoplasmic status at codon 143 of cytochrome b gene in QoI‐fungicide‐resistant B. cinerea from vineyards in Japan. With this assay, we demonstrated that the repeated introduction of QoI fungicide selection pressure increased the ratio of G143A‐mutated cytochrome b genes in B. cinerea isolates. Conclusion We propose that the semi‐quantitative AS‐PCR assay is a reliable tool for the detection of QoI fungicide‐resistant and the evaluation of homoplasmic/heteroplasmic status at codon 143 of cytochrome b gene in B. cinerea isolates.
      PubDate: 2014-07-26T04:36:00.972396-05:
      DOI: 10.1002/ps.3867
       
  • Expanding the SAR of Sulfoxaflor: the Synthesis and Biological Activity of
           N‐Heterocyclic Sulfoximines
    • Authors: Benjamin M. Nugent; Ann M. Buysse, Michael R. Loso, Jon M. Babcock, Timothy C. Johnson, M. Paige Oliver, Timothy P. Martin, Matthias S. Ober, Nneka Breaux, Andrew Robinson, Yelena Adelfinskaya
      Pages: n/a - n/a
      Abstract: Background Sulfoxaflor, a new insect control agent developed by Dow AgroSciences, exhibits broad spectrum control of many sap‐feeding insect pests, including aphids, whiteflies, leafhoppers, planthoppers, and lygus bugs. During the development of sulfoxaflor, SAR exploration of the sulfoximine functional group revealed the nature of the sulfoximine nitrogen substituent significantly affects insecticidal acitivity. As part of the investigation to probe the various electronic, steric and lipophilic parameters at this postion, a series of N‐heterocyclic sulfoximines were synthesized and tested for bioactivity against green peach aphid. Results Using a variety of chemistries, the nitrile substituent was replaced with different substituted 5‐ and 6‐membered heterocycles. The compounds in the series were then tested for insecticidal acitivty against green peach aphid in foliar spray assays. Despite the larger steric demand of these substituents, the resulting N‐heterocyclic sulfoximine analogs displayed good levels of efficacy. In particular, the N‐thiazolyl sulfoximines exhibited the greatest activity, with LC50 values as low as 1 ppm. Conclusions The novel series of N‐heterocyclic sulfoximines helped advance the knowledge of the sulfoxaflor SAR, and demonstrated that the structural requirement for the sulfoximine nitrogen position was not limited to small, electron deficient moeities, but rather was tolerant of larger functionality.
      PubDate: 2014-07-26T03:20:17.125736-05:
      DOI: 10.1002/ps.3865
       
  • Induced resistance by oxidative shifts in pigeonpea (Cajanus cajan L.)
           following Helicoverpa armigera (Hübner) herbivory
    • Authors: Rimaljeet Kaur; Anil K Gupta, Gaurav K Taggar
      Pages: n/a - n/a
      Abstract: BACKGROUND Oxidative responses in leaves, developing seeds and the pod wall of nine pigeonpea genotypes were investigated against Helicoverpa armigera feeding. Out of nine genotypes, four were moderately resistant, three were intermediate and two were moderately susceptible genotypes. RESULTS A significant shift in the oxidative status of pigeonpea following herbivory was depicted by the upregulation of diamine oxidase (DAO), polyamine oxidase (PAO) and lipoxygenase 2 (LOX 2) activities. Polyphenol oxidase (PPO) activity was significantly higher in the infested pod wall and leaves of moderately resistant genotypes than in those of moderately susceptible genotypes. H. armigera infestation markedly enhanced phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) activities in wounded tissues. The decline in ascorbate peroxidase (APX) activity and ascorbate content was lower in moderately resistant genotypes than in moderately susceptible genotypes. A significant decrease in LOX 3 activity was also observed in the infested pod wall of moderately resistant and intermediate genotypes. A lower malondialdehyde (MDA) content and higher proline content of the infested pod wall and developing seeds was observed. Higher activities of PPO, PAL and proline content in leaves of uninfested moderately resistant genotypes could either be an unrelated observation or alternatively could help in identifying H. armigera‐resistant genotypes. CONCLUSION The increase in activities of PPO, DAO, PAO, PAL and TAL and higher proline and lower MDA content upon herbivory suggested their integrated contribution in providing resistance to pigeonpea against H. armigera. © 2014 Society of Chemical Industry
      PubDate: 2014-07-25T08:47:20.138845-05:
      DOI: 10.1002/ps.3851
       
  • Pathogenicity bioassays of isolates of Beauveria bassiana on Rhynchophorus
           ferrugineus
    • Authors: Gabriella Lo Verde; Livio Torta, Vincenzo Mondello, Cesare G Caldarella, Santella Burruano, Virgilio Caleca
      Pages: n/a - n/a
      Abstract: BACKGROUND The control of Rhynchophorus ferrugineus (Olivier), the main palm pest in the Mediterranean Basin, is problematic because of its biology and the current restrictions in many European countries on the use of chemical insecticides in urban areas. Entomopathogenic fungi have been studied as potential biological control agents, but information on their natural incidence is limited. Strains of Beauveria bassiana (Balsamo) Vuillemin were isolated from symptomatic insects collected on dead palms, and their pathogenicity against different instars of R. ferrugineus was evaluated in the laboratory. RESULTS The overall percentage of infected insects found in Canary palms was 7%. In laboratory bioassays, hatching of eggs treated with three different isolates of B. bassiana was 41.2, 26.8 and 29.9%, significantly lower than the control (62.4%). Larvae and adults were treated with a single isolate in two ways: spraying each insect with a conidial suspension or feeding them with fruit portions previously immersed in the same conidial suspension. At the end of the two trials, the mortality of treated larvae was 88 and 92%, and the mean survival time was 10.4 and 11.8 days, significantly different from the control, where no insect died during the trials. Mortality and survival time recorded in either trial on adults did not significantly differ between treatment and control. CONCLUSION This study shows that the pathogenicity of wild isolates of B. bassiana differs among the tested R. ferrugineus instars. The low mortality of treated adults supports their use as vectors of B. bassiana as a potential tool for reducing R. ferrugineus populations. © 2014 Society of Chemical Industry
      PubDate: 2014-07-24T09:48:31.213934-05:
      DOI: 10.1002/ps.3852
       
  • Bait station devices can improve mass trapping performance for the control
           of the Mediterranean fruit fly
    • Authors: Vicente Navarro‐Llopis; Jaime Primo, Sandra Vacas
      Pages: n/a - n/a
      Abstract: Background The use of traps and other attract‐and‐kill devices in pest management strategies to reduce Mediterranean fruit fly populations has proven efficient. Nevertheless, many farmers are concerned about the effect of these devices on the trees where they are hung. Direct field observations have revealed that fruit damage is higher in trees with traps than in trees without them. This work evaluates the efficacy of different types of attract‐and‐kill devices to protect fruit of the single tree where the device is placed in. Results Results suggested that trees with traps had, at least, the same fruit damage than trees without them. When traps were baited with protein hyrolizate, fruit damage was even higher than in trees without traps. However, fruit damage is significantly diminished when efficient bait station devices are used. Conclusion Although mass trapping is able to control fruit fly populations as a control method, trees with some type of traps and baits are more susceptible to fly puncture. However, bait station devices reduce fruit damage in the single trees where they are hung. As a conclusion bait station resulted more efficient in fruit protection as fruit flies are affected as soon as they contact the device. Some recommendations for use of the different attract‐and‐kill devices are discussed.
      PubDate: 2014-07-24T04:36:49.253818-05:
      DOI: 10.1002/ps.3864
       
  • Activity‐temperature relationships in Meligethes aeneus:
           Implications for pest management
    • Authors: Andrew W. Ferguson; Lucy M. Nevard, Suzanne J. Clark, Samantha M. Cook
      Pages: n/a - n/a
      Abstract: Background Pollen beetle (Meligethes aeneus F.) management in oilseed rape (Brassica napus L.) has become an urgent issue in the light of insecticide resistance. Risk prediction advice has relied upon flight temperature thresholds while risk assessment uses simple economic thresholds. However, there is variation in the reported temperature of migration and economic thresholds vary widely across Europe; probably due to climatic factors interacting with beetle activity and plant compensation for damage. The effect of temperature on flight, feeding and oviposition activity of M. aeneus was examined in controlled conditions. Results Escape from a release vial was taken as evidence of flight and was supported by video observations. The propensity to fly followed a sigmoid temperature‐response curve between 6–23 °C; 10%, 25% and 50% flight temperature thresholds were 12.0–12.5 °C, 13.6–14.2 °C and 15.5–16.2 °C, respectively. Thresholds were slightly higher in the second of two flight bioassays, suggesting an effect of beetle age. We found strong positive relationships between temperature (6–20 °C) and the rates of feeding and oviposition on flower buds of oilseed rape. Conclusion These temperature relationships could be used to improve M. aeneus migration risk assessment, refine weather‐based decision support systems and modulate damage thresholds according to rates of bud damage.
      PubDate: 2014-07-23T03:54:14.749329-05:
      DOI: 10.1002/ps.3860
       
  • Perspectives on Transgenic, Herbicide‐Resistant Crops in the USA
           Almost 20 Years after Introduction
    • Authors: Stephen O. Duke
      Pages: n/a - n/a
      Abstract: Herbicide‐resistant crops have had profound impacts on weed management. Most of the impact has been by glyphosate‐resistant maize, cotton, soybean, and canola. Significant economic savings, yield increases, and more efficacious and simplified weed management resulted in widespread adoption of the technology. Initially, glyphosate‐resistant crops enabled significantly reduced tillage and reduced the environmental impact of weed management. Continuous use of glyphosate with glyphosate‐resistant crops over broad areas facilitated the evolution of glyphosate‐resistant weeds, which have resulted in increases in the use of tillage and other herbicides with glyphosate, reducing some of the initial environmental benefits of glyphosate‐resistant crops. Transgenic crops with resistance to auxinic herbicides, as well as to herbicides that inhibit acetolactate synthase, acetyl‐CoA carboxylase, and hydroxyphenylpyruvate dioxygenase, stacked with glyphosate and/or glufosinate resistance, will become available in the next few years. These technologies will provide additional weed management options for farmers, but will not have all of the positive impacts (reduced cost, simplified weed management, lowered environmental impact, and reduced tillage) that glyphosate‐resistant crops had initially. In the more distant future, other herbicide‐resistant crops (including non‐transgenic ones), herbicides with new modes of action, and technologies that are currently in their infancy (e.g., bioherbicides, sprayable herbicidal RNAi, and/or robotic weeding) may impact the role of transgenic, herbicide‐resistant crops in weed management.
      PubDate: 2014-07-23T03:39:08.764241-05:
      DOI: 10.1002/ps.3863
       
  • Detection of knockdown resistance (kdr) mutations in the Common bed bug,
           Cimex lectularius (Hemiptera: Cimicidae) in Australia.
    • Authors: Kai Dang; Cheryl S. Toi, David G. Lilly, Wenjun Bu, Stephen L. Doggett
      Pages: n/a - n/a
      Abstract: Background Pyrethroid resistance in the Common bed bug, Cimex lectularius L. has been reported worldwide. An important resistant mechanism is via knockdown resistance (kdr) mutations, notably V419L and L925I. Information regarding this kdr‐type resistant mechanism is unknown in Australia. This study aims to examine the status of kdr mutations in Australian C. lectularius strains. Results Several modern field‐collected strains and museum preserved reference collections of Australian C. lectularius were examined. Of the field strains (2007–2013), 96% had the known kdr‐mutations (L925I or both V419L/L925I). The ‘Adelaide’ strain (2013), and samples from the preserved reference collections (1994–2004), revealed no known kdr‐mutations. A novel mutation I936F was apparent in the insecticide‐resistant ‘Adelaide’ strain, one strain from Perth (with L925I), and the majority of the reference collection specimens. The laboratory insecticide‐resistant ‘Sydney’ strain showed a mixture of no kdr‐mutations (20%) and L925I (80%). Conclusion The novel mutation, I936F may be a kdr‐mutation but appeared to contribute less resistance to the pyrethroids than the V419L and L925I mutations. The detection of high frequencies of kdr mutations indicates that kdr‐type resistance is widespread across Australia. Hence, there should be a reduced reliance on pyrethroid insecticides and an integrated management approach for the control of C. lectularius infestations.
      PubDate: 2014-07-21T04:59:12.864813-05:
      DOI: 10.1002/ps.3861
       
  • Physiological Effects of Temperature on Turfgrass Tolerance to
           Amicarbazone
    • Authors: Jialin Yu; Patrick E. McCullough, Timothy Grey
      Pages: n/a - n/a
      Abstract: Background Amicarbazone effectively controls annual bluegrass (Poa annua L.) in bermudagrass (Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt‐Davy) and tall fescue (Festuca arundinacea Schreb.) with spring applications, but summer applications may excessively injure tall fescue. The objective of this research was to investigate physiological effects of temperature on amicarbazone efficacy, absorption, translocation, and metabolism in annual bluegrass, bermudagrass, and tall fescue. Results At 25/20 ºC (day/night), annual bluegrass absorbed 58 and 40% more foliar applied amicarbazone than bermudagrass and tall fescue, respectively, after 72 h. Foliar absorption increased at 40/35 ºC in all species, compared to 25/20 ºC, and tall fescue had similar absorption to annual bluegrass at 40/35 ºC. At 6 DAT, annual bluegrass metabolized 54% of foliar applied amicarbazone, while bermudagrass and tall fescue metabolized 67 and 64%, respectively. Conclusion Tall fescue is more tolerant to amicarbazone than annual bluegrass at moderate temperatures (≈25/20 ºC) due to less absorption and greater metabolism. However, tall fescue susceptibility to amicarbazone injury at high temperatures (40/35 ºC) results from enhanced herbicide absorption compared to lower temperatures (25/20 ºC). Bermudagrass is more tolerant to amicarbazone than annual bluegrass and tall fescue due to less herbicide absorption, regardless of temperature.
      PubDate: 2014-07-18T04:50:23.156623-05:
      DOI: 10.1002/ps.3853
       
  • Laboratory and field assessment of cyantraniliprole relative to existing
           fly baits
    • Authors: Amy C Murillo; Alec C Gerry, Nicola T Gallagher, Nyles G Peterson, Bradley A Mullens
      Pages: n/a - n/a
      Abstract: BACKGROUND Toxic fly baits are commonly used for fly control in California animal operations. However, resistance development has been a problem. Comprehensive laboratory and field studies were conducted to test commercial baits (imidacloprid, methomyl, dinotefuran, spinosad) and one novel cyantraniliprole bait. A susceptible Musca domestica strain was compared with wild‐type M. domestica and Fannia canicularis strains in the laboratory using choice/no‐choice tests. Field visitation to baits and both short‐ and longer‐term mortality were documented. RESULTS Susceptible Musca suffered high mortality with all baits after 3 days of choice and no‐choice tests. Wild‐type Musca mortality was more variable and higher in no‐choice relative to choice tests. Fannia were most susceptible to spinosad > dinotefuran = cyantraniliprole > methomyl = imidacloprid. Field Musca were most attracted to spinosad > cyantraniliprole > dinotefuran > sugar > methomyl > imidacloprid. Delayed mortality from bait‐fed field flies (captured and held with untreated food and water for 3 days) was ranked spinosad = cyantraniliprole > dinotefuran = methomyl > imidacloprid > sugar. CONCLUSION Behavioral resistance of M. domestica to imidacloprid and methomyl persists. Spinosad and cyantraniliprole baits (delayed mortality) performed best. Speed of action may be a factor in use and misuse of baits. © 2014 Society of Chemical Industry
      PubDate: 2014-07-15T10:22:23.135631-05:
      DOI: 10.1002/ps.3847
       
  • Prospects for control of apple leaf midge Dasineura mali (Diptera:
           Cecidomyiidae) by mass trapping with pheromone lures
    • Authors: Peter L Lo; James TS Walker, D Max Suckling
      Pages: n/a - n/a
      Abstract: Background Apple leaf midge, Dasineura mali (Kieffer), poses quarantine issues for some apple export markets because larvae occasionally pupate in the stem end and calyx of fruit. Pheromone‐baited oil‐filled containers in 1‐ha orchard plots trapped adult male D. mali to test the potential for mass trapping to reduce populations. Results Mass trapped plots had 97% fewer adult males in pheromone traps and 48% fewer larvae per shoot in the second D. mali generation compared with untreated areas. Oil traps caught on average 900,000 D. mali per plot over 11 weeks during the second and third generations. Catches averaged 9200/trap at plot corners. By comparison, catches were 51% lower 10–25 m away along borders, 80% lower at the midpoint of borders and 95% lower >7 m from plot edges. Fruit infestation was low (4/8000 apples). Conclusion The attractiveness of the pheromone, monophagous habit and low mobility of D. mali enhance the prospects for successful mass trapping. Countering this are high populations, multi‐voltinism and aspects of mating behaviour. Mass trapping would probably be more effective had it been in place season‐long and conducted over successive years. It needs refinements and more study before becoming a feasible control option for D. mali.
      PubDate: 2014-07-14T13:23:48.85129-05:0
      DOI: 10.1002/ps.3857
       
  • Protection of winter wheat against orange wheat blossom midge,
           Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae): efficacy of
           insecticides and cultivar resistance
    • Authors: Sandrine Chavalle; Florence Censier, Gilles San Martin y Gomez, Michel De Proft
      Pages: n/a - n/a
      Abstract: Background In 2012 and 2013, Sitodiplosis mosellana (Géhin) flights occurred during the susceptible phase of wheat development in Belgium. The protection against this midge afforded by various insecticides was assessed in infested fields on four winter wheat cultivars (susceptible or resistant, and early or late heading). Results The insecticides sprayed at the right time reduced the number of larvae in the ears by 44‐96%, depending on the product. For Julius, the cultivar (cv.) most exposed to S. mosellana in 2013, the mean yield gain resulting from insecticide use was 1,558 kg ha−1 (18%). In the same year, insecticide use resulted in a yield gain of 780 kg ha−1 (8%) for the cv. Lear, despite its resistance to this pest. The link between yield and number of larvae counted in the ears was a logarithmic relationship, suggesting an important reduction in yield caused either by the damage inflicted by young larvae which died at the start of their development or by the activation of costly reactions in plants. Conclusion The study showed that, in cases of severe attack, the timely application of insecticide treatments can protect wheat against S. mosellana and that even resistant cultivars can benefit from these treatments.
      PubDate: 2014-07-11T03:04:20.412309-05:
      DOI: 10.1002/ps.3855
       
  • Biofumigation with Brassica juncea, Raphanus sativus and Eruca sativa for
           the Management of Field Populations of the Potato Cyst Nematode Globodera
           pallida
    • Authors: B. M. Ngala; P.P.J. Haydock, S. Woods, M. A. Back
      Pages: n/a - n/a
      Abstract: Background The viability of potato cyst nematode (PCN) populations (Globodera pallida) was evaluated in three field experiments using Brassica juncea, Raphanus sativus and Eruca sativa amendments. These species were summer-cultivated and autumn-incorporated in Experiment-1; in Experiment-2, overwintered brassicaceous cover crops were spring-incorporated. Experiment-3 involved determination of effects of metconazole application on biomass/glucosinolate production by B. juncea and R. sativus and on PCN pre- and post-incorporation. Glucosinolate contents were determined before incorporation. Following cover crop incorporation, field plots were planted with susceptible potatoes to evaluate the biofumigation effects on PCN reproduction. Results In Experiment-1, PCN population post-potato harvest was reduced (P = 0.03) in B. juncea-treated plots, while R. sativus prevented further multiplication, but in Experiment-2, there were no significant effects on PCN reproduction. In Experiment-3, B. juncea or R. sativus either untreated or treated with metconazole reduced PCN populations. Glucosinolate concentrations varied significantly between different plant regions and cultivation seasons. Metconazole application increased sinigrin concentration in B. juncea tissues. Glucosinolate concentrations correlated positively with PCN mortality for summer-cultivated brassicaceous plants. Conclusion Our results demonstrated that Brassica juncea and Raphanus sativus green manures can play an important role in PCN management, particularly if included in an integrated pest management scheme.
      PubDate: 2014-06-25T12:28:43.11758-05:0
      DOI: 10.1002/ps.3849
       
  • Manipulating behaviour with substrate-borne vibrations – potential
           for insect pest control
    • Authors: J Polajnar; A Eriksson, A Lucchi, G Anfora, M Virant-Doberlet, V Mazzoni
      Pages: n/a - n/a
      Abstract: This review presents an overview of potential use of substrate-borne vibrations for the purpose of achieving insect pest control in the context of integrated pest management. Although the importance of mechanical vibrations in the life of insects has been fairly well established, the effect of substrate-borne vibrations has historically been understudied, in contrast to sound sensu stricto. Consequently, the idea of using substrate-borne vibrations for pest control is still in its infancy. Our review therefore focuses on theoretical background, using it to highlight potential applications in field environment, and lists the few preliminary studies that have been or are being performed. We also note conceptual similarities with the use of sound, as well as limitations inherent in this approach.
      PubDate: 2014-06-24T12:43:32.834097-05:
      DOI: 10.1002/ps.3848
       
  • Frequency of V1016I and F1534C mutations in the voltage-gated sodium
           channel gene in Aedes aegypti of Venezuela.
    • Authors: Leslie C. Alvarez; Gustavo Ponce, Karla Saavedra, Beatriz Lopez, Adriana E. Flores
      Abstract: Background The V1016I and F1534C mutations in the voltage-gated sodium channel gene have been associated with resistance to pyrethroids and DDT in Aedes aegypti mosquitoes. In this study, we determined the frequency of I1016 and C1534 by real time PCR in five natural populations of Ae. aegypti in Venezuela during 2008, 2010 and 2012, as well as in a strain selected with 0.14 µg of deltamethrin for 15 generations. Results In natural populations, frequencies of I1016 varied between 0.01 and 0.37; and for C1534 between 0.35 and 1.0. In Pampanito strain, the frequency of I1016 increased from 0.02 in F1 up to 0.5 in F15 and from 0.35 up to fixation for C1534 after selection with deltamethrin. Conclusion Our results showed that C1534 frequencies are higher in natural populations of Ae. aegypti in Venezuela compared with I1016 and that deltamethrin selected the C1534 more rapidly than I1016.
      PubDate: 2014-06-17T04:02:52.048232-05:
      DOI: 10.1002/ps.3846
       
  • Estimating development of the fennel aphid, Hyadaphis foeniculi
           (Passerini) (Hemiptera: Aphiididae) using nonlinear models
    • Authors: J. B. Malaquias; F.S. Ramalho, A.C.S. Lira, F.Q. Oliveira, F.S. Fernandes, J.C. Zanuncio, W.A.C. Godoy
      Abstract: Background Nonlinear models allowing us to predict agricultural pest outbreaks and optimize control tactics are of primary importance for Integrated Pest Management. The development period for immature stages of Hiadaphis foeniculi (Passerini) (Hemiptera: Aphididae) at constant temperatures was modeled in order to determine mathematical functions for simulating the aphid's development. Nonlinear models were used to describe the relationship between temperature and development rates H. foeniculi subjected to constant temperatures. Results The models used were found to be good fits for estimating H. foeniculi development rates as a function of temperature, with the exception of the Davidson model. The development time of H. foeniculi nymphs ranged from 2.73 days (1st instar) to 6.18 days (4th instar) at 15 °C, 2.57 days (1st instar) to 4.52 days (4th instar) at 20 °C and 1.53 days (1st instar) to 2.05 days (4th instar) at 28 °C. Conclusion These models provide important tools for better elucidating the relationship between temperature and development rates in H. foeniculi. The results could be used for predicting the occurrence of the various immature stages of H. foeniculi in the fennel crop in Brazil, allowing us to more accurately predict the best periods for implementing pest control.
      PubDate: 2014-06-13T15:20:31.095013-05:
      DOI: 10.1002/ps.3845
       
  • Toxicity of hiba oil constituents and spray formulations to American house
           dust mites and copra mites
    • Authors: Jun-Ran Kim; Haribalan Perumalsamy, Min Jung Kwon, Se Um Chae, Young-Joon Ahn
      Abstract: Background Dermatophagoides farinae and Tyrophagus putrescentiae are recognized as an important source of allergens. An assessment was made of the toxicity of hiba, Thujopsis dolabrata var. hondai, oil and 13 organic compounds and the control efficacy of four experimental spray formulations containing the oil (5–30 g L−1 sprays) against both mite species. Results In a contact + fumigant mortality bioassay, (−)-thujopsene was the most toxic constituent against D. farinae and T. putrescentiae (24 h LC50, 9.82 and 10.92 µg/cm2) and the toxicity of the compound was nearly identical to that of benzyl benzoate (9.33 and 10.14 µg/cm2). The toxicity was more pronounced in carvacrol, (+)-terpinen-4-ol, β-thujaplicin, (−)-terpinen-4-ol, cedrol and α-terpineol (LC50, 12.05–15.20 and 12.74–16.48 µg/cm2) than N,N-diethyl-3-methylbenzamide (LC50, 35.53 and 38.42 µg/cm2) against both mite species. The hiba oil 30 g L−1 spray and commercial permethrin (cis:trans, 25:75) 2.5 g L−1 spray treatment resulted in 100 and 11% mortality against both mite species respectively. In vapour-phase mortality tests, the two compounds were consistently more toxic in closed versus open containers, indicating that toxicity was achieved mainly through the action of vapour. Conclusion Reasonable mite control in indoor environments can be achieved by spray formulation containing the 30 g L−1 hiba oil as potential contact-action fumigants.
      PubDate: 2014-06-10T12:01:26.485344-05:
      DOI: 10.1002/ps.3843
       
  • Polyenylcyclopropane carboxylic esters with high insecticidal activity
    • Authors: Claudia Ferroni; Lucio Bassetti, Valerio Borzatta, Elisa Capparella, Carlotta Gobbi, Alberto Guerrini, Greta Varchi
      Abstract: Background Pyrethroids are synthetic derivatives of naturally occurring pyrethrum. These molecules are widely used in agriculture for ant, flies and mosquito control and for lawn and garden care. Pyrethroids are the optically active esters of 2,2-dimethyl-3-(2-methylpropenyl)-cyclopropane carboxylic acid, also known as chrysanthemic acid. However, their intense use resulted in the development of resistance in many insect species. We report herein specific structural modifications of pyrethroids’ scaffold and their effect on insecticidal activity, especially on resistant pests strains. Results The exposure to (1R)-trans-(E/Z)-2,3,5,6-tetrafluorobenzyl-3-(buta-1,3-dienyl)-2,2-dimethyl cyclopropanecarboxylate and its diastereomers, produced 100% mortality in yellow fever mosquitoes (Aedes aegypti), house mosquitoes (Culex quinquefasciatus) and houseflies (Musca domestica). Besides, this compound provided a complete knockdown (KT100) within 15 minutes of exposure against cockroaches (Blattella germanica) and maintained an excellent knockdown activity after 10 days from treatment. Conclusion In conclusion, we describe novel pyrethroid derivatives obtained from 2,2-dimethyl-3-(2-methylpropenyl)-cyclopropanecarboxylic acid, which display high insecticidal activity, a wide spectrum of action and no toxicity towards mammalians. Moreover, the described synthetic procedures are highly efficient and inexpensive, therefore suitable for industrial scale-up.
      PubDate: 2014-06-05T04:23:01.59148-05:0
      DOI: 10.1002/ps.3842
       
  • Enantioselective bioaccumulation and toxic effects of fipronil in the
           earthworm Eisenia foetida following soil exposure
    • Authors: Fang Qin; Yongxin Gao, Peng Xu, Baoyuan Guo, Jianzhong Li, Huili Wang
      Abstract: Background Enantiomers of chiral pesticides often have different bioactivity, toxicity, and environmental behaviors. Fipronil has been used in racemate for agricultural purposes against soil insects, leading to increased inputs into soil environments and complex biota exposures. To understand the potential risk associated with fipronil enantiomers exposure, subchronic toxicity and bioaccumulation tests with earthworms (Eisenia foetida) in fipronil-spiked soils were evaluated under laboratory condition. Results Enantioselective toxicity was measured in E. foetida biomass after 28-days of subchronic exposure, with increased toxicity from racemate and S-fipronil compared with R-fipronil. The bioaccumulation of fipronil in earthworm tissues was also enantioselective with a preferential accumulation of S-fipronil and the enantiomer fraction were approximately 0.56-0.60. During the soil exposure, fipronil was transformed primarily into fipronil sulfide, sulfone, and amide, and E. foetida rapidly accumulated fipronil and sulfone. Conclusion This work points out the enantioselective subchronic toxicity and bioaccumulation of enantiomers of fipronil in E. foetida. The earthworm tissues exhibited a relative enrichment of fipronil and fipronil sulfone, and these compounds might biomagnify (with a biota-to-soil accumulation factor ≥1.0 kgOC kglip−1) allowing for the possible trophic transfer and/or bioaccumulation of all these chemicals if earthworms were consumed by predator organisms.
      PubDate: 2014-06-05T03:20:13.493968-05:
      DOI: 10.1002/ps.3841
       
  • Population management of Rock Hyraxes (Procavia capensis) in residential
           areas
    • Authors: Roelof E Wiid; Hennie J B Butler
      Abstract: Background Frequent reports of rock hyrax (Procavia capensis) invasions in residential areas led to the investigation of this problem as well as identification of possible solutions. From these reports, problem areas in South Africa were identified and sites within the Free State Province were selected for this study. At these sites populations demonstrate an unusual annual increase. This increase led to a food and habitat shortage forcing individuals into residential areas in search of additional refuges and food sources. In order to manage populations, several preventive as well as control methods were assessed and implemented. Population densities were determined using the Lincoln Index and the Robson-Whitlock Technique. Wild populations were included in the study for comparison purposes. Results Additional resources within residential areas supported populations to grow much larger and some exceeded the natural limits, 30 to 40 individuals, by 470%. This influx contributes to human-wildlife conflict. With the use of relocation populations were reduced within three months. Discussion Preventive methods showed various levels of success. Specific combinations of these methods proved more successful than others. To capture and relocate individuals, in order to rapidly decrease a population, was successful. Preliminary results show that establishing relocated populations was not successful due to high predation rates. The reintroduction of natural predators for rock hyrax population control seemed successful but will have to be monitored in a regular basis.
      PubDate: 2014-06-04T12:40:18.964669-05:
      DOI: 10.1002/ps.3840
       
  • Neonicotinoid Concentrations in Arable Soils After Seed Treatment
           Applications in Preceding Years
    • Authors: Ainsley Jones; Paul Harrington, Gordon Turnbull
      Abstract: Background Concentrations of the neonicotinoid insecticides clothianidin, thiamethoxam and imidacloprid were determined in arable soils from a variety of locations in England Results In soil samples taken from the central area of fields, concentrations of clothianidin ranged from 0.02 µg/kg to 13.6 µg/kg. Thiamethoxam concentrations were between
      PubDate: 2014-05-29T03:53:42.43197-05:0
      DOI: 10.1002/ps.3836
       
  • Quantifying the past and future impact of climate on outbreak patterns of
           bank voles (Myodes glareolus)
    • Authors: Christian Imholt; Daniela Reil, Jana A. Eccard, Daniela Jacob, Nils Hempelmann, Jens Jacob
      Abstract: Background Central European outbreak populations of the bank vole (Myodes glareolus Schreber) are known to cause damage in forestry and to transmit the most common type of Hantavirus (Puumala virus, PUUV) to humans. A sound estimation of potential effects of future climate scenarios on population dynamics is prerequisite for long-term management strategies. Historic abundance time series were used to identify the key weather conditions associated with bank vole abundance, and extrapolated to future climate scenarios to derive potential long-term changes in bank vole abundance dynamics. Results Classification and regression tree analysis revealed the most relevant weather parameters associated with high and low bank vole abundances. Summer temperatures two years prior to trapping had the highest impact on abundance fluctuation. Extrapolation of the identified parameters to future climate conditions revealed an increase of years with high vole abundance. Conclusion Key weather pattern associated with vole abundance reflect the importance of superabundant food supply through masting on the occurrence of bank vole outbreaks. Due to changing climate these outbreaks are predicted to potentially increase in frequency 3-4 fold by the end of this century. This may negatively affect damage patterns in forestry and the risk of human PUUV infection in the long-term.
      PubDate: 2014-05-29T03:46:26.92273-05:0
      DOI: 10.1002/ps.3838
       
  • Susceptibility of Tuta absoluta (Lepidoptera: Gelechiidae) Brazilian
           populations to ryanodine receptor modulators
    • Authors: Mateus R. Campos; Tadeu B. M. Silva, Wellington M. Silva, Jefferson E. Silva, Herbert A. A. Siqueira
      Abstract: Background Phthalic and anthranilic diamides comprise a new insecticide class recently registered in Brazil to control Lepidoptera such as the Tuta absoluta (Meyrick). Therefore, the baseline of susceptibility was determined for eight representative field populations of this species to establish a resistance monitoring program. The potential of cross-resistance as well as detoxification metabolism were assessed to fine-tune the resistance management program. Results Brazilian populations were very susceptible to chlorantraniliprole (LC50s varied from 3.17 to 29.64 µg AI L−1), cyantraniliprole (LC50s varied from 8.61 to 28.95 µg AI L−1), and flubendiamide (LC50s varied from 94 to 230 µg AI L−1) with respective resistance ratios of 9.33-, 3.36-, and 2.45- times between most susceptible and tolerant populations. Anthranilic diamides showed significant correlations between logarithm LC50 values among themselves, suggesting a high risk of cross-resistance. However, the logarithm LC50s of T. absoluta to phthalic diamide did not show any correlation with anthranilic diamides. Cytochrome P450-dependent monooxygenase activity showed a weak correlation with logarithm LC50 values of T. absoluta populations to anthranilic diamides, which suggests a potential route for evolving resistance to anthranilic diamides. Conclusion The diamides were highly effective against T. absoluta with populations showing a homogeneous response to them. Cross-resistance is highly expected between anthranilic diamides in T. absoluta. Populations of this pest may evolve resistance by increasing cytochrome P450–dependent monooxygenases.
      PubDate: 2014-05-24T05:36:42.25946-05:0
      DOI: 10.1002/ps.3835
       
  • Synthesis and antifungal evaluation of a series of maleimides
    • Authors: Xiao-Long Chen; Li-Jun Zhang, Fu-Ge Li, Yong-Xian Fan, Wei-Ping Wang, Bao-Ju Li, Yin-Chu Shen
      Abstract: Backgound Maleimides, both natural and synthesized, have good biological activities. In our continuous effort to discover new maleimides with good antifungal activities, we have synthesized a series of 3, 4-dichloro-, 3-methyl and non-substituted maleimides based on the previous studies. The compounds were biologically evaluated against the fungal pathogen Sclerotinia sclorotiorum. Results 25 of 63 compounds had interesting inhibitory potency with EC50 < 10 µg/mL. Among evaluated compounds, N-(3,5-dichlorophenyl)-3,4-dichloromaleimide (EC50= 1.11 µg/mL) and N-octyl-3-methylmaleimide (EC50 = 1.01 µg/mL) were more potent than the commercial fungicides dicloran (EC50=1.72 µg/mL). The results showed that compounds exhibiting LogP values within the range 2.4-3.0 displayed the best results in terms of fungicidal activity and it seemed, therefore, to be the optimal range for this physicochemical parameter. Conclusion The present work demonstrates that some maleimides can be used as potential lead compounds for developing novel antifungal agents against S. sclerotiorum.
      PubDate: 2014-05-05T09:02:11.958935-05:
      DOI: 10.1002/ps.3824
       
  • Development of an Efficient Trapping System for New Zealand Flower Thrips,
           Thrips obscuratus
    • Authors: Warwick J Allen; Vanessa J Mitchell, Kate Colhoun, Bernie A Attfield, Mailee E Stanbury, David M Suckling, Ashraf M El-Sayed
      Abstract: Background New Zealand flower thrips (NZFT), Thrips obscuratus (Crawford), is an economic pest of various horticultural crops in New Zealand and is recognised as a quarantine pest globally. We investigated two chemical attractants (ethyl nicotinate and 6-pentyl-2H-pyran-2-one), three dispensers, three trap designs, and four trap heights to determine the most effective method for monitoring NZFT. Phenology of NZFT at two locations was compared. Results 6-pentyl-2H-pyran-2-one in a polyethylene bag dispenser was the most attractive lure formulation, and exhibited high stability in release rate trials. There was no difference in NZFT catch between vertical panel and cross panel traps, but both caught significantly more than delta traps. However, both types of panel trap had unacceptably high by-catch of native insects. Catch of thrips increased with height from zero to three metres. Phenology of NZFT showed similar population trends at both locations, but with a timing difference of around 50 days. Conclusions Delta traps containing 6-pentyl-2H-pyran-2-one in a polyethylene bag at two metres above the ground is the recommended method for monitoring NZFT, significantly improving the sensitivity, accuracy, and labour input compared to prior methods. Long-term monitoring of NZFT could lead to more accurate economic damage thresholds and timing for when to apply insecticides.
      PubDate: 2014-05-05T09:01:25.390567-05:
      DOI: 10.1002/ps.3823
       
  • Global Herbicide Resistance Challenge
    • Authors: Stephen Powles
      Pages: 1305 - 1305
      PubDate: 2014-07-17T09:51:06.47385-05:0
      DOI: 10.1002/ps.3808
       
  • Global perspective of herbicide‐resistant weeds
    • Authors: Ian Heap
      Pages: 1306 - 1315
      Abstract: Two hundred and twenty weed species have evolved resistance to one or more herbicides, and there are now 404 unique cases (species × site of action) of herbicide‐resistant weeds globally. ALS inhibitor‐resistant weeds account for about a third of all cases (133/404) and are particularly troublesome in rice and cereals. Although 71 weed species have been identified with triazine resistance, their importance has dwindled with the shift towards Roundup Ready® crops in the USA and the reduction of triazine usage in Europe. Forty‐three grasses have evolved resistance to ACCase inhibitors, with the most serious cases being Avena spp., Lolium spp., Phalaris spp., Setaria spp. and Alopecurus myosuroides, infesting more than 25 million hectares of cereal production globally. Of the 24 weed species with glyphosate resistance, 16 have been found in Roundup Ready® cropping systems. Although Conyza canadensis is the most widespread glyphosate‐resistant weed, Amaranthus palmeri and Amaranthus tuberculartus are the two most economically important glyphosate‐resistant weeds because of the area they infest and the fact that these species have evolved resistance to numerous other herbicide sites of action, leaving growers with few herbicidal options for their control. The agricultural chemical industry has not brought any new herbicides with novel sites of action to market in over 30 years, making growers reliant on using existing herbicides in new ways. In addition, tougher registration and environmental regulations on herbicides have resulted in a loss of some herbicides, particularly in Europe. The lack of novel herbicide chemistries being brought to market combined with the rapid increase in multiple resistance in weeds threatens crop production worldwide. © 2013 Society of Chemical Industry
      PubDate: 2014-01-15T08:38:00.675104-05:
      DOI: 10.1002/ps.3696
       
  • Mechanisms of resistance to paraquat in plants
    • Authors: Timothy R Hawkes
      Pages: 1316 - 1323
      Abstract: The aim of this brief review is to draw information from studies of the mechanism of evolved resistance in weeds, together with information from laboratory studies of paraquat tolerance in model plants. Plants having mutations that limit paraquat uptake into cytoplasm, that confer various stress tolerances or that have transgenes that co‐express two or more of the chloroplast Halliwell–Asada cycle enzymes can all exhibit enhanced tolerance to paraquat. However, none of these mechanisms correspond to the high‐level resistances that have evolved naturally in weeds. Most, but not all, of the evidence from studies of paraquat‐resistant biotypes of weeds can reasonably be reconciled with the proposal of a single major gene mechanism that sequesters paraquat away from chloroplasts and into the vacuole. However, the molecular details of this putative mechanism remain ill‐defined. © 2013 Society of Chemical Industry
      PubDate: 2014-01-21T10:55:53.131738-05:
      DOI: 10.1002/ps.3699
       
  • Management of herbicide resistance in wheat cropping systems: learning
           from the Australian experience
    • Authors: Michael J Walsh; Stephen B Powles
      Pages: 1324 - 1328
      Abstract: Herbicide resistance continues to escalate in weed populations infesting global wheat (Triticum aestivum L.) crops, threatening grain production and thereby food supply. Conservation wheat production systems are reliant on the use of efficient herbicides providing low‐cost, selective weed control in intensive cropping systems. The resistance‐driven loss of herbicide resources combined with limited potential for new herbicide molecules means greater emphasis must be placed on preserving existing herbicides. For more than two decades, since the initial recognition of the dramatic consequences of herbicide resistance, the challenge of introducing additional weed control strategies into herbicide‐based weed management programmes has been formidable. Throughout this period, herbicide resistance has expanded unabated across the world's wheat production regions. However, in Australia, where herbicide resources have become desperately depleted, the adoption of harvest weed seed control is evidence, at last, of a successful approach to sustainable weed management in wheat production systems. Growers routinely including strategies to target weed seeds during crop harvest, as part of herbicide‐based weed management programmes, are now realising significant weed control and crop production benefits. When combined with an attitude of zero weed tolerance, there is evidence of a sustainable weed control future for wheat production systems. The hard‐learned lessons of Australian growers can now be viewed by global wheat producers as an example of how to stop the continual loss of herbicide resources in productive cropping systems. © 2013 Society of Chemical Industry
      PubDate: 2014-01-20T04:10:20.194833-05:
      DOI: 10.1002/ps.3704
       
  • The future for weed control and technology
    • Authors: Dale L Shaner; Hugh J Beckie
      Pages: 1329 - 1339
      Abstract: This review is both a retrospective (what have we missed?) and prospective (where are we going?) examination of weed control and technology, particularly as it applies to herbicide‐resistant weed management (RWM). Major obstacles to RWM are discussed, including lack of diversity in weed management, unwillingness of many weed researchers to conduct real integrated weed management research or growers to accept recommendations, influence or role of agrichemical marketing and governmental policy and lack of multidisciplinary research. We then look ahead to new technologies that are needed for future weed control in general and RWM in particular, in areas such as non‐chemical and chemical weed management, novel herbicides, site‐specific weed management, drones for monitoring large areas, wider application of ‘omics’ and simulation model development. Finally, we discuss implementation strategies for integrated weed management to achieve RWM, development of RWM for developing countries, a new classification of herbicides based on mode of metabolism to facilitate greater stewardship and greater global exchange of information to focus efforts on areas that maximize progress in weed control and RWM. There is little doubt that new or emerging technologies will provide novel tools for RMW in the future, but will they arrive in time? © 2013 Her Majesty the Queen in Right of Canada Pest Management Science © 2013 Society of Chemical Industry
      PubDate: 2014-01-31T05:23:58.568484-05:
      DOI: 10.1002/ps.3706
       
  • Resistance to AHAS inhibitor herbicides: current understanding
    • Authors: Qin Yu; Stephen B Powles
      Pages: 1340 - 1350
      Abstract: Acetohydroxyacid synthase (AHAS) inhibitor herbicides currently comprise the largest site‐of‐action group (with 54 active ingredients across five chemical groups) and have been widely used in world agriculture since they were first introduced in 1982. Resistance evolution in weeds to AHAS inhibitors has been rapid and identified in populations of many weed species. Often, evolved resistance is associated with point mutations in the target AHAS gene; however non‐target‐site enhanced herbicide metabolism occurs as well. Many AHAS gene resistance mutations can occur and be rapidly enriched owing to a high initial resistance gene frequency, simple and dominant genetic inheritance and lack of major fitness cost of the resistance alleles. Major advances in the elucidation of the crystal structure of the AHAS (Arabidopsis thaliana) catalytic subunit in complex with various AHAS inhibitor herbicides have greatly improved current understanding of the detailed molecular interactions between AHAS, cofactors and herbicides. Compared with target‐site resistance, non‐target‐site resistance to AHAS inhibitor herbicides is less studied and hence less understood. In a few well‐studied cases, non‐target‐site resistance is due to enhanced rates of herbicide metabolism (metabolic resistance), mimicking that occurring in tolerant crop species and often involving cytochrome P450 monooxygenases. However, the specific herbicide‐metabolising, resistance‐endowing genes are yet to be identified in resistant weed species. The current state of mechanistic understanding of AHAS inhibitor herbicide resistance is reviewed, and outstanding research issues are outlined. © 2013 Society of Chemical Industry
      PubDate: 2014-01-20T10:59:42.723314-05:
      DOI: 10.1002/ps.3710
       
  • Current state of herbicides in herbicide‐resistant crops
    • Authors: Jerry M Green
      Pages: 1351 - 1357
      Abstract: Current herbicide and herbicide trait practices are changing in response to the rapid spread of glyphosate‐resistant weeds. Growers urgently needed glyphosate when glyphosate‐resistant crops became available because weeds were becoming widely resistant to most commonly used selective herbicides, making weed management too complex and time consuming for large farm operations. Glyphosate made weed management easy and efficient by controlling all emerged weeds at a wide range of application timings. However, the intensive use of glyphosate over wide areas and concomitant decline in the use of other herbicides led eventually to the widespread evolution of weeds resistant to glyphosate. Today, weeds that are resistant to glyphosate and other herbicide types are threatening current crop production practices. Unfortunately, all commercial herbicide modes of action are over 20 years old and have resistant weed problems. The severity of the problem has prompted the renewal of efforts to discover new weed management technologies. One technology will be a new generation of crops with resistance to glyphosate, glufosinate and other existing herbicide modes of action. Other technologies will include new chemical, biological, cultural and mechanical methods for weed management. From the onset of commercialization, growers must now preserve the utility of new technologies by integrating their use with other weed management technologies in diverse and sustainable systems. © 2014 Society of Chemical Industry
      PubDate: 2014-02-24T12:08:32.218363-05:
      DOI: 10.1002/ps.3727
       
  • Evolution of resistance to phytoene desaturase and protoporphyrinogen
           oxidase inhibitors – state of knowledge
    • Authors: Franck E Dayan; Daniel K Owens, Patrick J Tranel, Christopher Preston, Stephen O Duke
      Pages: 1358 - 1366
      Abstract: Two major classes of herbicides include inhibitors of protoporphyrinogen oxidase (PPO) and phytoene desaturase (PDS). Plants can evolve resistance to PPO and PDS inhibitors via several mechanisms that include physical changes, resulting in reduced uptake, physiological changes, resulting in compartmentalization or altered translocation, and biochemical changes, resulting in enhanced metabolic degradation or alterations of protein structures, leading to loss of sensitivity to the herbicides. This review discusses the involvement of some of these mechanisms in the various cases of resistance to PDS‐ and PPO‐inhibiting herbicides, and highlights unique aspects of target‐site resistance to these herbicides. © 2014 Society of Chemical Industry
      PubDate: 2014-02-24T12:09:06.573481-05:
      DOI: 10.1002/ps.3728
       
  • Glyphosate resistance: state of knowledge
    • Authors: Robert Douglas Sammons; Todd A Gaines
      Pages: 1367 - 1377
      Abstract: Studies of mechanisms of resistance to glyphosate have increased current understanding of herbicide resistance mechanisms. Thus far, single‐codon non‐synonymous mutations of EPSPS (5‐enolypyruvylshikimate‐3‐phosphate synthase) have been rare and, relative to other herbicide mode of action target‐site mutations, unconventionally weak in magnitude for resistance to glyphosate. However, it is possible that weeds will emerge with non‐synonymous mutations of two codons of EPSPS to produce an enzyme endowing greater resistance to glyphosate. Today, target‐gene duplication is a common glyphosate resistance mechanism and could become a fundamental process for developing any resistance trait. Based on competition and substrate selectivity studies in several species, rapid vacuole sequestration of glyphosate occurs via a transporter mechanism. Conversely, as the chloroplast requires transporters for uptake of important metabolites, transporters associated with the two plastid membranes may separately, or together, successfully block glyphosate delivery. A model based on finite glyphosate dose and limiting time required for chloroplast loading sets the stage for understanding how uniquely different mechanisms can contribute to overall glyphosate resistance. © 2014 The
      Authors . Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
      PubDate: 2014-03-12T10:30:31.084642-05:
      DOI: 10.1002/ps.3743
       
  • Resistance to herbicides inhibiting the biosynthesis of
           very‐long‐chain fatty acids
    • Authors: Roberto Busi
      Pages: 1378 - 1384
      Abstract: Herbicides that act by inhibiting the biosynthesis of very‐long‐chain fatty acids (VLCFAs) have been used to control grass weeds in major crops throughout the world for the past 60 years. VLCFA‐inhibiting herbicides are generally highly selective in crops, induce similar symptoms in susceptible grasses and can be found within the herbicide groups classified by the HRAC as K3 and N. Even after many years of continuous use, only 12 grass weed species have evolved resistance to VLCFA‐inhibiting herbicides. Here, the cases of resistance that have evolved in major grass weed species belonging to the Avena, Echinochloa and Lolium genera in three different agricultural systems are reviewed. In particular we explore the possible reasons why VLCFA herbicides have been slow to select resistant weeds, outline the herbicide mode of action and discuss the resistance mechanisms that are most likely to have been selected. © 2014 Society of Chemical Industry
      PubDate: 2014-03-10T11:42:59.468183-05:
      DOI: 10.1002/ps.3746
       
  • Expanding the eco‐evolutionary context of herbicide resistance
           research
    • Authors: Paul Neve; Roberto Busi, Michael Renton, Martin M Vila‐Aiub
      Pages: 1385 - 1393
      Abstract: The potential for human-driven evolution in economically and environmentally important organisms in medicine, agriculture and conservation management is now widely recognised. The evolution of herbicide resistance in weeds is a classic example of rapid adaptation in the face of human-mediated selection. Management strategies that aim to slow or prevent the evolution of herbicide resistance must be informed by an understanding of the ecological and evolutionary factors that drive selection in weed populations. Here, we argue for a greater focus on the ultimate causes of selection for resistance in herbicide resistance studies. The emerging fields of eco-evolutionary dynamics and applied evolutionary biology offer a means to achieve this goal and to consider herbicide resistance in a broader and sometimes novel context. Four relevant research questions are presented, which examine (i) the impact of herbicide dose on selection for resistance, (ii) plant fitness in herbicide resistance studies, (iii) the efficacy of herbicide rotations and mixtures and (iv) the impacts of gene flow on resistance evolution and spread. In all cases, fundamental ecology and evolution have the potential to offer new insights into herbicide resistance evolution and management. © 2014 Society of Chemical Industry
      PubDate: 2014-04-09T03:39:51.810655-05:
      DOI: 10.1002/ps.3757
       
  • Herbicide resistance modelling: past, present and future
    • Authors: Michael Renton; Roberto Busi, Paul Neve, David Thornby, Martin Vila‐Aiub
      Pages: 1394 - 1404
      Abstract: Computer simulation modelling is an essential aid in building an integrated understanding of how different factors interact to affect the evolutionary and population dynamics of herbicide resistance, and thus in helping to predict and manage how agricultural systems will be affected. In this review, we first discuss why computer simulation modelling is such an important tool and framework for dealing with herbicide resistance. We then explain what questions related to herbicide resistance have been addressed to date using simulation modelling, and discuss the modelling approaches that have been used, focusing first on the earlier, more general approaches, and then on some newer, more innovative approaches. We then consider how these approaches could be further developed in the future, by drawing on modelling techniques that are already employed in other areas, such as individual‐based and spatially explicit modelling approaches, as well as the possibility of better representing genetics, competition and economics, and finally the questions and issues of importance to herbicide resistance research and management that could be addressed using these new approaches are discussed. We conclude that it is necessary to proceed with caution when increasing the complexity of models by adding new details, but, with appropriate care, more detailed models will make it possible to integrate more current knowledge in order better to understand, predict and ultimately manage the evolution of herbicide resistance. © 2014 Society of Chemical Industry
      PubDate: 2014-04-28T05:29:13.51685-05:0
      DOI: 10.1002/ps.3773
       
  • Resistance to acetyl‐CoA carboxylase‐inhibiting herbicides
    • Authors: Shiv S Kaundun
      Pages: 1405 - 1417
      Abstract: Resistance to acetyl‐CoA carboxylase herbicides is documented in at least 43 grass weeds and is particularly problematic in Lolium, Alopecurus and Avena species. Genetic studies have shown that resistance generally evolves independently and can be conferred by target‐site mutations at ACCase codon positions 1781, 1999, 2027, 2041, 2078, 2088 and 2096. The level of resistance depends on the herbicides, recommended field rates, weed species, plant growth stages, specific amino acid changes and the number of gene copies and mutant ACCase alleles. Non‐target‐site resistance, or in essence metabolic resistance, is prevalent, multigenic and favoured under low‐dose selection. Metabolic resistance can be specific but also broad, affecting other modes of action. Some target‐site and metabolic‐resistant biotypes are characterised by a fitness penalty. However, the significance for resistance regression in the absence of ACCase herbicides is yet to be determined over a practical timeframe. More recently, a fitness benefit has been reported in some populations containing the I1781L mutation in terms of vegetative and reproductive outputs and delayed germination. Several DNA‐based methods have been developed to detect known ACCase resistance mutations, unlike metabolic resistance, as the genes remain elusive to date. Therefore, confirmation of resistance is still carried out via whole‐plant herbicide bioassays. A growing number of monocotyledonous crops have been engineered to resist ACCase herbicides, thus increasing the options for grass weed control. While the science of ACCase herbicide resistance has progressed significantly over the past 10 years, several avenues provided in the present review remain to be explored for a better understanding of resistance to this important mode of action. © 2014 Society of Chemical Industry
      PubDate: 2014-05-06T08:01:06.595167-05:
      DOI: 10.1002/ps.3790
       
  • Fluridone: a combination germination stimulant and herbicide for problem
           fields?
    • Authors: Danica E Goggin; Stephen B Powles
      Pages: 1418 - 1424
      Abstract: BACKGROUND Problem weeds in agriculture, such as Lolium rigidum Gaud., owe some of their success to their large and dormant seed banks, which permit germination throughout a crop‐growing season. Dormant weed seed banks could be greatly depleted by application of a chemical that stimulates early‐season germination and then kills the young seedlings. Fluridone, a phytoene desaturase‐inhibiting herbicide that can also break seed dormancy, was assessed for its efficacy in this regard. RESULTS The germination of fluridone‐treated Lolium rigidum seeds was stimulated on soils with low organic matter, and almost 100% seedling mortality was observed, while the treatment was only moderately effective on a high‐organic‐matter potting mix. Seedlings from wheat, canola, common bean and chickpea seeds sown on fluridone‐treated sandy loam were bleached and did not survive, but lupins and field peas grew normally. CONCLUSION This proof‐of‐concept study with fluridone suggests that it may be possible to design safe and effective molecules that act as germination stimulants plus herbicides in a range of crop and soil types: a potentially novel way of utilising herbicides to stimulate seed bank germination and a valuable addition to an integrated weed management system. [[ArtCopyrightmsg]]
      PubDate: 2014-02-13T10:56:30.056769-05:
      DOI: 10.1002/ps.3721
       
  • Pollen‐mediated transfer of herbicide resistance in Echinochloa
           crus‐galli
    • Authors: Muthukumar V Bagavathiannan; Jason K Norsworthy
      Pages: 1425 - 1431
      Abstract: BACKGROUND Pollen‐mediated gene flow (PMGF) can facilitate the dispersal and spread of herbicide resistance from one weed population to another within an agricultural landscape. The aim of this study was to quantify the extent of PMGF in Echinochloa crus‐galli (barnyardgrass), an important herbicide‐resistant weed species in the United States and across the world. RESULTS Gene flow declined exponentially with distance, and the double exponential decay model predicted an average gene flow of 5.6% when the pollen donor and recipient plants were at a close distance of 0.25 m from each other (12.5% at 0 m). Gene flow declined by 90% at 0.9 m from the pollen source, yet gene flow was detected as far as 50 m (the farthest distance studied). The farthest gene flow occurred in directions of the fastest wind events, but mean gene flow levels were similar among the directions. CONCLUSION Results indicate that long‐distance, landscape‐scale PMGF is unlikely in barnyardgrass, but gene flow is likely to occur between adjacent fields at levels greater than initial frequencies of resistance alleles in natural, unselected populations. Thus, any resistance management strategy should consider the likelihood that PMGF can contribute to the spread of herbicide resistance between production fields. © 2014 Society of Chemical Industry
      PubDate: 2014-04-16T10:06:26.604943-05:
      DOI: 10.1002/ps.3775
       
  • Identification of the first glyphosate‐resistant wild radish
           (Raphanus raphanistrum L.) populations
    • Authors: Michael B Ashworth; Michael J Walsh, Ken C Flower, Stephen B Powles
      Pages: 1432 - 1436
      Abstract: BACKGROUND In Australia, glyphosate has been used routinely to control wild radish (Raphanus raphanistrum L.) for the past 40 years. This study focuses on two field‐evolved glyphosate‐resistant populations of wild radish collected from the grainbelt of Western Australia. RESULTS Two wild radish biotypes were confirmed to be glyphosate resistant by comparing R/S of two suspected populations. Based on R/S from dose–response curves, the R1 and R2 populations were 2.3 and 3.2 times more resistant to glyphosate respectively. Dose response on glyphosate‐selected progeny (>1080 g ha−1) demonstrated that the glyphosate resistance mechanism was heritable. When compared with the pooled mortality results of three known susceptible populations (S1, S2 and S3), the R1 and R2 subpopulations were 3.4‐fold and 4.5‐fold more resistant at the LD50 level respectively. Both populations were found to have multiple resistance to the phytoene desaturase inhibitor; diflufenican, the synthetic auxin; 2,4‐D and the ALS inhibitors; chlorsulfuron, sulfometuron‐methyl, imazethapyr and metosulam. CONCLUSIONS This is the first report confirming glyphosate resistance evolution in wild radish and serves to re‐emphasise the importance of diverse weed control strategies. Proactive and integrated measures for resistance management need to be developed to diversify control measures away from glyphosate and advance the use of non‐herbicidal techniques. © 2014 Society of Chemical Industry
      PubDate: 2014-05-15T09:35:29.27469-05:0
      DOI: 10.1002/ps.3815
       
 
 
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