Progress 11/04/10 to 06/30/15

Outputs
Progress Report Objectives (from AD-416): Develop knowledge and control tactics based on the physiology, biochemistry, genetics and vector-pathogen interactions of insect pests. Characterize and exploit interactions among plants, insect pests and natural enemies; investigate the role of arthropod predators and trophic interactions for improved biological control. Characterize flight behavior and dispersal of insect pests and natural enemies; elucidate relationships among landscape structure, pest and natural enemy biology and dispersal behavior. Refine sampling strategies for insect pests and their associated natural enemies; develop and refine economic thresholds for sucking pests in cotton that incorporate biological control potential; support post-eradication detection of pink bollworm populations. Refine insecticide-based management strategies; characterize factors influencing resistance to chemical insecticides and insecticidal proteins in transgenic crops; evaluate insecticide selectivity; support post- eradication pink bollworm resistance monitoring in Bt cotton. Approach (from AD-416): Research will build a solid foundation of fundamental tactics for avoiding pest problems and will strengthen prescriptive pest control through refinement of monitoring, decision aids and effective treatment options. Research will explore and exploit the molecular and chemical basis of male-derived factors on female mating inhibition and hormonal factors regulating reproduction and diapause in Lygus. hesperus, the molecular basis of water channel proteins in Bemisia tabaci, the impact of plant virus and plant allelochemical mediated changes on B. tabaci fitness and insecticide resistance, respectively, and the molecular basis of Bt resistance in Pectinophora gossypiella. Further research will exploit semiochemicals and tri-trophic interactions for enhanced biological control, and identify insect and plant based semiochemicals enabling mating disruption and improved monitoring of B. tabaci and L. hesperus. Flight behavior and inter- and intra-crop dispersal of L. hesperus, and source-sink relationships for arthropod predators inhabiting the agro-ecosystem will be quantified, facilitating IPM at the landscape scale. Selective insecticides and improved decision aids that account for natural enemy abundance will be evaluated and developed for B. tabaci in cotton. Research will further support P. gossypiella post- eradication efforts through refinement of pheromone-based monitoring systems and detection of resistance to Bt cotton. This is the final report for this project, which expired in June 2015. The project is replaced by 2020-22620-022-00D, "Ecologically Based Pest Management Strategies for Arid Land Crops." Progress was made on all five objectives, which fall under National Program 304, Component 3, Insects and Mites, Subcomponent 3A, Agricultural and Horticultural Cropping Systems, Problem Statement 3A2, Systems approach to environmentally sound pest management. Objective 1: Males of the western tarnished plant bug (Lygus) were found to transfer a key hormone to females at mating. The hormone (juvenile hormone) suppressed female mating but promoted egg laying by changing the concentrations of brain hormones in the female. A chemical transferred from male to female Lygus at mating was identified and found to inhibit mating by making the female unattractive to males, but this activity was counteracted with time by a breakdown product of the anti-mating chemical. Differences in basal metabolism of reproductive and diapausing Lygus adults were documented and a visual method to distinguish diapause was developed. Diapause was shown to enhance host-free survival of Lygus adults, but additional work showed that adult survival under wintertime temperatures was sufficient to allow substantial overwintering by non- diapausing insects. Shifts in gene expression during Lygus development were documented and studies were started to associate these shifts with changes in hormone titers. In addition, mechanisms regulating insect development were explored by manipulating hormone levels and expression of genes. Photoperiod response of Lygus diapause was modeled and validated, including the critical photoperiod. Temperature dependence of development and survival under constant temperatures was defined for all Lygus stages, and studies of egg development under variable temperatures were completed. A catalog of genes expressed in adult Lygus was developed that identified potential targets for molecular disruption including genes that respond to insecticides and thermal stress. Totals of five and seven specific proteins that control water balance (aquaporins) were identified from whitefly and Lygus, respectively. Plant extracts were identified that disrupted function of these proteins. Injection methods to silence genes in whitefly and Lygus were developed but efforts continue to find methods to silence Lygus genes through feeding. Virus infection of cotton was shown to increase leaf sugar content and increase whitefly population levels compared with uninfected plants. Also, whitefly females on virus-infected plants survived heat stress better than females on uninfected plants. These collective results provide the basis for continued efforts to devise control tactics that maximize the impacts of environmental stressors on pest populations. Objective 2: Efforts to use natural enemy attractants in cotton were unsuccessful. Male Lygus were found to transfer hormones during mating which produced shifts in brain chemicals in the mated females. Candidate proteins used by male Lygus to identify mated females were identified and compared to similar proteins in a sister species, the tarnished plant bug. Five proteins in Lygus antennae were identified that likely function in chemical communication. Key genetic sequences from Lygus antennae were assembled and annotated to provide a comprehensive reference for future work. Chemicals used by female Lygus to attract males were identified and tested in the field. Improved methods of characterizing dose-dependent insect responses to attractive chemicals were developed, and a conceptual model of pest response to attractants was constructed. Studies were started to examine effects of host plant on natural enemy effectiveness against whitefly. Objective 3: Studies showed that Lygus adults fly under a narrow range of temperatures. Investigations of the effects of host plant on Lygus flight were started. Simulations of insect response to traps will facilitate determining optimal trap height for capturing pest insects. Lygus were found to feed on buds and developing seeds of four new industrial crops (camelina, guayule, lesquerella, veronia), but all stages of Lygus fed less on camelina than on the other crops. Protein marking methods were used to define the range of pollinator movement between conventional and transgenic crops. Marking methods using inexpensive common proteins (egg, milk, and soybean) were developed to reduce the cost of research, and these markers were broadcast to demonstrate the ability of trap crops to concentrate Lygus adults and thereby protect adjacent strawberries. Methods to predict abundance of Lygus in specific cotton fields were developed based on surrounding crop types. Studies to quantify colonization of cotton by Lygus from cut alfalfa are ongoing. Molecular analyses of gut contents of insect predators showed that target pests (Lygus, whitefly) are more often fed on by insect predators than by spiders. Methods using protein markers for studying predation were validated and used to distinguish predation from cannibalism and scavenging by selected predators. These results have direct application in better understanding pest dispersal and its implications to management. Objective 4: Studies showed that Lygus feeding did not impact yield or quality of lesquerella (a new oil-seed crop) when the crop was properly managed. Progress was also made in documenting the pest and beneficial insect complexes in another oil-seed crop, guayule. New treatment thresholds for sweetpotato whitefly in cotton were developed that incorporated impacts of natural enemies. The thresholds were demonstrated and validated in producer fields, and the technology is being transferred to producers in two western states and northern Mexico. This threshold work was facilitated by use of a new sampling method that employed a rapid knockdown insecticide. Impacts of cotton irrigation regime on population levels of Lygus, whitefly, and key natural enemies were demonstrated in the field. Lygus populations were more influenced by plant condition than natural enemies manipulated through insecticide treatments, whereas whitefly populations were affected more by natural enemies than plant quality as influenced by irrigation management. A review of world literature on the economics of biological control estimated economic returns for the three primary biological control approaches (classical, augmentative, and conservation). The importance of releases of sterile pink bollworm moths to suppression of resistance development to Bt cotton was demonstrated. Progress was also made in optimizing trap-based pink bollworm monitoring through computer simulations. Efforts to develop plant-based attractants for cotton pests were largely unsuccessful. The collective results provide improved guides for producers in making pest treatment decisions. Objective 5: Studies of a common class of whitefly insecticides (neonicotinoids) used in cantaloupes near honeybee colonies showed the insecticide can be exuded from plant leaves under some conditions, which may pose a hazard to foraging bees. An improved system for monitoring insecticide resistance in whitefly was developed that uses a combination of field- and laboratory-based assays. A new bioassay method was developed for evaluating insecticide response by the Bagrada bug, and new insecticide toxicity data were collected for the glassy-wing sharpshooter, green peach aphid, and four species of insect predator. Predation on pests feeding on transgenic insecticidal (Bt) corn or cotton was shown to have no direct negative effects on a beetle predator, three true bug predators, a predatory mite, or a parasitic wasp. Comprehensive protocols for collecting and evaluating field-based data on effects of Bt-crops on non-target organisms were developed and transferred to other scientists and regulatory agencies. Studies indicated whiteflies exhibit different levels of resistance to different neonicotinoid insecticides. Host plant (broccoli, cantaloupe, and cotton) differentially induced a suite of detoxification enzymes in the whitefly that influenced insecticide toxicity. Whiteflies feeding on hosts that most stimulate expression of detoxification genes also were less fit than whiteflies feeding on hosts that did not elicit a strong reaction, suggesting an ecological cost of detoxification. Ongoing studies of differences in these enzymes indicate a higher diversity of detoxification enzymes in sucking insects that feed on phloem (the plant nutrient transport system) than for insects that feed on xylem (the plant water transport system). Ongoing studies of defensive chemicals in cotton suggested Lygus was little affected by the common cotton toxicant (gossypol), but survival and reproduction was reduced when other defensive mechanisms were induced by chewing pests. Four altered cell-adhesion proteins (cadherins) associated with resistance of laboratory-selected pink bollworm to Bt toxins were identified and analyses showed a mobile element (jumping gene) was involved in producing these proteins. However, analysis of Bt-resistant pink bollworm from India revealed a wide diversity of altered cadherins as well as novel mechanisms for their alteration. Laboratory selections yielded a pink bollworm strain with high levels of resistance to both Bt toxins used in dual-toxin cotton varieties, and the inheritance of resistance to both toxins was determined. Collaborations are ongoing to determine the genetic sequences associated with the altered cadherins as well as another class of possible Bt-toxin receptor (ABC transporter proteins). The normal cadherin that confers susceptibility to Bt toxins has been cloned into insect cell lines for studies of toxin binding and toxicity. These results contribute to critically important efforts to maintain effectiveness of current synthetic and transgenic pest control tools. Accomplishments 01 Transgenic crops do not affect important arthropod parasitoids and predators. Bt transgenic crops are cultivated on millions of hectares globally, but there remain concerns about the risks these crops may impose on non-target organisms like arthropod natural enemies that supply important ecological services. ARS scientists from the Arid-Land Agricultural Research Center, Maricopa, Arizona, and Ames, Iowa, researchers at Cornell University, Ithaca, New York, and Agroscope, Zurich, Switzerland, showed that the development and reproduction of a parasitic wasp, a predatory beetle, three predatory true bugs, a predatory mite and a predatory green lacewing over multiple generations were not affected by ingestion of prey that had fed on Bt plants. The natural enemy species tested represent some of the most abundant and important species in cropping systems. The prey used were either resistant to or not susceptible to the Bt proteins in the plants. This approach eliminates prey quality issues, allowing the direct effects of Bt proteins to be accurately assessed under realistic exposure scenarios. Results are valuable to governmental authorities responsible for regulating transgenic crops, scientists concerned with developing integrated pest management strategies for pest control, and a general public concerned about the environmental effects of biotechnology. 02 Economic value of biological control. Biological control is an underlying pillar of integrated pest management, but little focus has been placed on assigning economic value to this key ecosystem service. An ARS scientist from the Arid-Land Agricultural Research Center, Maricopa, Arizona, in collaboration with scientists from the University of Arizona, reviewed, synthesized and analyzed the world literature on biological control economics. The benefit:cost ratios for classical (introductory) biological control range from 1:1 to > 10,000:1 while augmentative biological control compares with chemical insecticides with an average benefit:cost ratio of about 2.5-5:1. The economic value of the conservation of natural enemies, a third approach to biological control, has been poorly studied, but the synthesis here suggests values of up to >$2000/hectare depending on the crop system. The study further identified some of the challenges of applying economics to biological control to advance integrated pest management and provides a conceptual outline and catalog of methods for how biological control can be valued by fully accounting for all internal and external costs and benefits. Understanding the economic value of biological control will help to broaden its utility in crop protection and raise its stock among all stakeholders of agriculture, including those who make funding decisions that spur needed innovations.

Impacts
(N/A)

Publications

• Hull, J.J., Chaney, K., Geib, S.M., Fabrick, J.A., Brent, C.S., Walsh, D., Lavine, L.C. 2014. Transcriptome-based identification of ABC transporters in the western tarnished plant bug Lygus hesperus. PLoS ONE. 9(11):e113046.
• Hull, J.J., Wang, M. 2014. Molecular cloning and characterization of G alpha proteins from the western tarnished plant bug, Lygus hesperus. Insects. 6(1):54-76.
• Hagler, J.R., Naranjo, S.E., Machtley, S.A., Blackmer, F. 2014. Development of a standardized protein immunomarking protocol for insect mark-capture dispersal research. Journal of Applied Entomology. 138:772- 782.
• Hagler, J.R., Machtley, S.A., Blackmer, F. 2015. A potential sampling error associated with insect protein mark-capture data. Entomologia Experimentalis et Applicata. 154:28-34.
• Byers, J.A. 2014. Response to Martini and Habeck: Semiochemical dose- response curves fit by kinetic formation functions. Journal of Chemical Ecology. 40:1165-1166.
• Cooper, W.R., Spurgeon, D.W. 2015. Temperature-dependent survival of adult Lygus hesperus (Hemiptera: Miridae). Environmental Entomology. 44:808-813.
• Qui, L., Hou, L., Zhang, B., Liu, L., Li, B., Deng, P., Ma, W., Wang, X., Fabrick, J.A., Chen, L., Lei, C. 2015. Cadherin is a functional receptor of bacillus thuringiensis toxin Cry2Aa in the beet armyworm, spodoptera exigua. Journal of Invertebrate Pathology. 127:47-53.
• Fabrick, J.A., Wu, YiDong. 2015. Roles of insect midgut cadherin in Bt intoxication and resistance. In: Soberon, M., Gao, Y., Bravo, A., editors. Bt resistance-characterization and strategies for GM crops expressing Bacillus thuringiensis toxins. Boston, MA: CABI Crop Protection Compendium. 4:69-86.
• Lavine, L.C., Gotoh, H., Brent, C.S., Dworkin, I., Emlen, D. 2015. Exaggerated trait growth in insects. Annual Review of Entomology. 60:453- 472.
• Su, H.H., Tian, J., Naranjo, S.E., Romeis, J., Hellmich, R.L., Shelton, A. M. 2015. Bacillus thuringiensis plants expressing Cry1Ac, Cry2Ab and Cry1F are not toxic to the assassin bug, Zelus renardii. Journal of Applied Entomology. 139:23-30.
• Byers, J.A., Naranjo, S.E. 2014. Detection and monitoring of pink bollworm moths and invasive insects using pheromone traps and encounter rate models. Journal of Applied Ecology. 51:1041-1049.
• Romeis, J., Meissle, M., Naranjo, S.E., Li, Y., Bigler, F. 2014. The end of a myth � Bt(Cry1Ab) maize does not harm green lacewings. Frontiers in Plant Science. 5:391. doi: 10.3389/fpls.2014.00391.
• Naranjo, S.E., Ellsworth, P.C., Frisvold, G.B. 2015. Economic value of biological control in integrated pest management of managed plant systems. Annual Review Of Entomology. 60:621-645.
• Luthi, C., Alvarez-Alfageme, F., Li, Y., Naranjo, S.E., Higgins, T.J.V., Romeis, J. 2015. Potential of the bean alpha-amylase inhibitor alpha-AI-1 to inhibit alpha-amylase activity in true bugs(Hemiptera). Journal of Applied Entomology. 139:192-200.
• Terrapon, N., Li, C., Robertson, H.M., Ji, L., Meng, X., Booth, W., Chen, Z., Childers, C.P., Glastad, K.M., Gokhale, K., Gowin, J., Gronenberg, W., Hermansen, R.A., Hu, H., Hunt, B.G., Huylmans, I., Khalil, S.M., Mitchell, R., Munoz-Torres, M.C., Mustard, J., Pan, H., Reese, J.T., Scharf, M.E., Sun, F., Vogel, H., Xiao, J., Yang, W., Yang, Z., Yang, Z., Zhou, J., Zhu, J., Brent, C.S., Elsik, C.G., Goodisman, M.A., Liberles, D.A., Roe, R.M., Vargo, E.L., Vilcinskas, A., Wang, J., Bornberg-Bauer, E., Korb, J., Zhang, G., Liebig, J. 2014. The draft genome of a termite illuminates alternative social organization. Nature Communications. 5:3636.
• Naranjo, S.E. 2014. Effects of GM crops on non-target organisms. In: Ricroch, A. Chopra, S., Fleischer, S.J., editors. Plant biotechnology - experience and future prospects. Dordrecht-Heidelberg-London-New York. Springer. p. 129-142.
• Fleischer, S.J., Hutchison, W.D., Naranjo, S.E. 2014. Sustainable management of insect-resistant crops. In: Ricroch, A., Chopra, S., Fleischer, S.J., editors. Plant biotechnology - experience and future prospects. Dordrecht-Heidelberg-London-New York: Springer. p. 115-127.

Progress 10/01/13 to 09/30/14

Outputs
Progress Report Objectives (from AD-416): Develop knowledge and control tactics based on the physiology, biochemistry, genetics and vector-pathogen interactions of insect pests. Characterize and exploit interactions among plants, insect pests and natural enemies; investigate the role of arthropod predators and trophic interactions for improved biological control. Characterize flight behavior and dispersal of insect pests and natural enemies; elucidate relationships among landscape structure, pest and natural enemy biology and dispersal behavior. Refine sampling strategies for insect pests and their associated natural enemies; develop and refine economic thresholds for sucking pests in cotton that incorporate biological control potential; support post-eradication detection of pink bollworm populations. Refine insecticide-based management strategies; characterize factors influencing resistance to chemical insecticides and insecticidal proteins in transgenic crops; evaluate insecticide selectivity; support post- eradication pink bollworm resistance monitoring in Bt cotton. Approach (from AD-416): Research will build a solid foundation of fundamental tactics for avoiding pest problems and will strengthen prescriptive pest control through refinement of monitoring, decision aids and effective treatment options. Research will explore and exploit the molecular and chemical basis of male-derived factors on female mating inhibition and hormonal factors regulating reproduction and diapause in Lygus. hesperus, the molecular basis of water channel proteins in Bemisia tabaci, the impact of plant virus and plant allelochemical mediated changes on B. tabaci fitness and insecticide resistance, respectively, and the molecular basis of Bt resistance in Pectinophora gossypiella. Further research will exploit semiochemicals and tri-trophic interactions for enhanced biological control, and identify insect and plant based semiochemicals enabling mating disruption and improved monitoring of B. tabaci and L. hesperus. Flight behavior and inter- and intra-crop dispersal of L. hesperus, and source-sink relationships for arthropod predators inhabiting the agro-ecosystem will be quantified, facilitating IPM at the landscape scale. Selective insecticides and improved decision aids that account for natural enemy abundance will be evaluated and developed for B. tabaci in cotton. Research will further support P. gossypiella post- eradication efforts through refinement of pheromone-based monitoring systems and detection of resistance to Bt cotton. In efforts to characterize the hormonal regulation of reproductive development and diapause induction in the western tarnished plant bug, Lygus hesperus, altered expression of specific genes associated with the transition from the immature stage to adulthood in other insects was also observed in late-instar and young adult lygus. Experiments were initiated to associate gene expression levels to changes in endocrine titers. Studies to describe the functional relationship between daylength and diapause expression in Lygus hesperus were completed. Preliminary results of ongoing studies of temperature-dependent Lygus egg development indicate development times observed under constant temperatures poorly represent development times observed under fluctuating temperatures near upper- and lower-temperature thresholds. Studies of the composition of male-derived factors rendering mated Lygus hesperus females unattractive after mating revealed that males transfer substantial quantities of juvenile hormone with the spermatophore. Topical application of juvenile hormone to unmated females did not reduce female receptivity to mating, but elicited shifts in neurotransmitter levels associated with post-mating changes in reproductive behavior. In collaboration with other ARS scientists (Wapato, Wahsington), a putative lygus sex peptide receptor was stably transfected into mammalian cell lines. Profiling of corresponding RNA transcriptomes of accessory glands of mated and unmated males yielded 17,000 transcripts, and efforts to validate control genes were initiated. Efforts to elucidate the recognition mechanisms used by male lygus to identify receptive females prompted transcriptomic analyses of male and female antennae which yielded 30,000 transcripts. Annotated sequences were deposited in the National Center for Biotechnology Information repository. Studies were initiated to develop RNA interference-based knockdown methods to determine the efficacy of transcript knockdown on selected phenotypes. Lygus hesperus chemosensory proteins were identified and comparative analyses with Lygus lineolaris (tarnished plant bug) genes were performed. Experiments to define temporal patterns of degradation of the low-volatility anti-aphrodisiac in recently mated female Lygus hesperus were completed. In continuing studies to characterize functional aquaporin water transport proteins in the silverleaf whitefly, Bemisia tabaci, full- length DNA sequences of seven aquaporins were cloned. The diversity of aquaporins suggests RNA-interference targeting of single aquaporin genes will be ineffective because of compensation by other genes. Therefore, additional testing of combinations of aquaporin double-stranded RNAs are needed. Studies indicated the five functional aquaporins previously identified in Lygus hesperus were associated primarily with organ systems functioning in water exchange to maintain normal physiology. The Lygus aquaporins represented different genetic families, exhibited unique expression profiles and cellular localization, and were all functional transporters of water. Disruption of water transport function in one of the Lygus aquaporins by selected plant extracts was demonstrated, and these plant extracts exhibited insecticidal activity when included in artificial diets provided to either Lygus or whiteflies. Active components of the plant extracts await identification and may represent a new insecticidal mode of action specifically targeting aquaporins. To better document pathogen-mediated changes in host plants and their impact on vector populations, experiments were initiated to evaluate the use of insecticides to prevent transmission of Cucurbit Yellow Stunting Disorder Virus by whitefly. Studies to evaluate the diversity and incidence of vectors of Pierce�s disease in Arizona vineyards continued. The objective of characterizing semiochemical systems of key insect pests for use in methods of pest control was addressed by continued research to determine effective attraction radii of the sex pheromones of the plant bugs Lygus hesperus and Lygus lineolaris. Models of pest flight and invasive species detection exemplified by the pink bollworm moth were also constructed. Research with collaborators from Israel to identify a whitefly attractive pheromone revealed a possible aggregation pheromone component for further testing. Ongoing research to examine the influence of induced plant defense compounds (terpenoids) in Bt and non-Bt cotton on the biology and population dynamics of Lygus hesperus and key natural enemies addresses the objective of characterizing and exploiting interactions among plants, insect pests and natural enemies. Refinement and implementation of molecular gut content assays to evaluate predation on sucking insect pests and associated multi-trophic level interactions were facilitated by improvements in protein markers used to study insect dispersal and insect predation. The markers were used to study both the movement patterns of pests and natural enemies in the field and to evaluate insect predation. Evaluation of a new insect sampling method utilizing a rapid knockdown insecticide was continued. Insect predator gut contents were examined for prey remains to identify food chain interactions such as cannibalism and scavenging. The objective of incorporating information on natural enemies into decision aids for sucking cotton pests was addressed by on-farm demonstration and implementation of new biological control based economic thresholds for whitefly. Efforts to develop monitoring systems based on plant derived and other attractants were addressed by models of mass trapping developed for a fruit orchard pest (almond bark beetle) as well as for the lesser date moth. Analysis of colored nettings covering herb plantings was done in cooperation with Israeli researchers. Video analysis software was developed for use in behavioral bioassays involving the identification of Mediterranean fruit fly pheromone components. A new bioassay developed for Bagrada bug using tissue culture medium with embedded neonicotinoid insecticide for systemic uptake by test plants will facilitate evaluations of insecticide selectivity. Baseline responses of California and Arizona populations of green peach aphid to Sivanto (a member of a new class of insecticides, the butenolides) and two other insecticide products was determined. Progress was made in identifying cytochrome P450 oxidases that are upregulated in the whitefly, Bemisia tabaci, according to particular feeding hosts. These investigations contribute to understanding the role of enzyme induction by plant allelochemicals in whitefly susceptibility to pesticides. In an effort to characterize mechanisms of resistance to Bt Cry proteins and monitor resistance to Bt proteins by pink bollworm in the field, studies of Bt resistant pink bollworms from India were completed. All known Cry1Ac Bt resistant strains of pink bollworm from Arizona exhibit changes to one or more cadherin genes. Analyses of these genes from resistant India pink bollworms revealed a unique set of mutations compared with those identified from Arizona. These results implicate cadherin as a critical source of Bt resistance in pink bollworm. A new strain of pink bollworm called BtZ-R was created with high levels of resistance to the Bt proteins produced in first- and second-generation Bt cottons (Cry1Ac and Cry2Ab). Survival of BtZ-R on cotton plants producing both toxins was demonstrated. Laboratory crosses of Bt4R-2 with a Bt- susceptible strain and laboratory diet feeding tests revealed inheritance of the resistance trait was autosomal and completely recessive. Accomplishments 01 Alfalfa trap crop for lygus bugs in strawberry. Lygus bugs are major pests of strawberries that reduce yields and diminish quality of the fruit. An ARS scientist at Maricopa, Arizona, and collaborators at the University of California at Santa Cruz, demonstrated the efficacy of alfalfa trap crop strips for protecting commercial strawberries. In addition to attracting lygus bugs, the alfalfa strips tended to concentrate natural enemies of the pest. This method is being adopted by both conventional and organic strawberry producers to reduce dependency on conventional chemical controls. 02 Identification of critical genes in the western tarnished plant bug. Although the western tarnished plant bug is widely recognized as an important crop pest in the western U.S., little information is available regarding its molecular biology and physiology. ARS scientists from Maricopa, Arizona, identified 65 members of a gene family (the ABC transporters) known from other organisms to function in protein synthesis, reproductive development, and the elimination of toxins. A subset of these genes likely to function in pesticide resistance was further identified. These results suggest possible targets for genetic-based pest control and provides a broad baseline for future research to develop species-specific non-insecticidal control tactics. 03 Host plant induction of detoxification enzymes in relation to insecticide resistance. Insects that feed on many types of host plants are often exposed to a variety of plant defensive chemicals that are toxic to the insect. The mechanisms these insects use to eliminate or detoxify plant defensive chemicals may also deactivate certain insecticides. ARS scientists at Maricopa, Arizona, identified a suite of detoxification enzymes in the silverleaf whitefly that are stimulated when the insects feed on specific hosts. Increased tolerance to selected insecticides was also associated with increased activity of the detoxification enzymes. Improved understanding of the influence of host plant on the effectiveness of insecticides is an important consideration to the design of sustainable management strategies for the silverleaf whitefly. 04 Novel molecular mechanisms associated with pink bollworm resistance to transgenic Bt cotton. Although the pink bollworm is a major cotton pest worldwide, the advent of insecticidal Bt cotton has revolutionized management and suppression of this pest. However, recent emergence of highly-resistant field populations of pink bollworm in Asia accentuates the need to understand the molecular basis of Bt-resistance. When an ARS researcher in Maricopa, Arizona, and collaborators at the University of Arizona, analyzed field-collected pink bollworm from India, they found a diversity of genetic changes conferring resistance, including a novel mechanism called alternative splicing. These findings represent the first example of alternative splicing associated with Bt resistance that developed in the field. Because a diversity of resistance mechanisms were identified from only a few field-collected pink bollworm, current methods to detect resistance based on specific genetic changes may not be effective. 05 Improved characterization of semiochemical dose response functions. Most dose-response relationships in insect ecology are presumed to be logarithmic, although logarithmic functions often provide poor representations of experimental observations. An ARS scientist from Maricopa, Arizona, simulated interactions between a hypothetical volatile scent and the receptors on insect antennae and found that, in general, enzyme kinetic functions provided better descriptions of the simulated interactions than did logarithmic functions. As well, the kinetic functions generally provided adequate descriptions of results from the published literature. The use of kinetic functions in lieu of logarithmic functions to characterize dose-response relationships will improve insights gleaned from studies of insect chemical communications. 06 A novel chemical regulating mating in the western tarnished plant bug. During mating, the male of the western tarnished plant bug transfers a chemical signal to the female that renders her temporarily unattractive to other males, as is known to occur in a number of insect species. ARS scientists at Maricopa, Arizona, demonstrated that, in this plant bug, the anti-mating chemical signal degrades over time to produce a new signal that enhances female attractiveness to potential mates. This phenomenon of competing chemical signals is unreported from other species. These results enhance understanding of plant bug chemical ecology and mating dynamics, and may lead to development of new methods of ecologically-based management. 07 Systematic review protocols for assessing non-target effects in Bt crops. Transgenic Bt crops are widely cultivated globally but there remain concerns about environmental risk, particularly the effects of these crops on non-target organisms. An ARS researcher in Maricopa, Arizona, and collaborators at Agroscope, Zurich, Switzerland, developed comprehensive and scientifically-based protocols for collecting and assessing field-based research on non-target organisms occurring in crop fields and surrounding margins. Primarily European stakeholders from academia, regulatory authorities, industry, and civil society organizations were given the opportunity to comment on the review protocols. The open access global literature database developed will be subject of meta-analysis to discover broad and specific trends and effects. Results are valuable to governmental authorities responsible for regulating transgenic crops, other scientists, and a general public concerned with the environmental effects of biotechnology.

Impacts
(N/A)

Publications

• Zilnik, G., Hagler, J.R. 2013. An immunological approach to distinguish arthropod viviphagy from necrophagy. Biocontrol. 58:807-814.
• Callier, V., Shingleton, A.W., Brent, C.S., Ghosh, S.M., Kim, J., Harrison, J. 2013. The role of reduced oxygen in the developmental physiology of growth and metamorphosis initiation in Drosophila. Journal of Experimental Biology Online. 216:4334-4340.
• Swezey, S.L., Nieto, D.J., Pickett, C.H., Hagler, J.R., Bryer, J.A., Machtley, S.A. 2014. Dispersion and movement of the Lygus spp.parasitoid Peristenus relictus (Hymenoptera: Braconidae) in trapcropped organic strawberries. Environmental Entomology. 42(2):363-369.
• Tian, J.C., Long, L.P., Wang, X.P., Naranjo, S.E., Romeis, J., Hellmich, R. L., Wang, P., Shelton, A.M. 2014. Using resistant prey demonstrates that Bt plants producing Cry1Ac, Cry2Ab and Cry1F have no negative effects on Geocoris punctipes and Orius insidiosus. Environmental Entomology. 43:242- 251.
• Tabashnik, B.E., Fabrick, J.A., Unnithan, G.C., Yelich, A.J., Masson, L., Zhang, J., Bravo, A., Soberon, M. 2013. Efficacy of genetically modified Bt toxins alone and in combinations against pink bollworm resistant to Cry1Ac and Cry2Ab. PLoS One. 8(11):e80496.
• Hull, J.J., Perera, O.P., Snodgrass, G.L. 2014. Cloning and expression profiling of odorant-binding proteins in the tarnished plant bug, Lygus lineolaris. Insect Molecular Biology. 23(1):78-97.
• Kelly, J.L., Hagler, J.R., Kaplan, I. 2014. Semiochemical lures reduce emigration and enhance pest control services in open-field predator augmentation. Biological Control. 71:70-77.
• Fabrick, J.A., Pei, J., Hull, J.J., Yool, A.J. 2014. Molecular and functional characterization of multiple aquaporin water channel proteins from the western tarnished plant bug, Lygus hesperus. Insect Biochemistry and Molecular Biology. 45:125-140.
• Hull, J.J., Brent, C.S. 2014. Identification and characterization of a sex peptide receptor-like transcript from the western tarnished plant bug, Lygus hesperus. Insect Molecular Biology. 23:301-319.
• Meissle, M., Naranjo, S.E., Kohl, C., Riedel, J., Romeis, J. 2014. Does the growing of Bt maize change populations or ecological functions of non- target animals compared to the growing of conventional non-GM maize? A systematic review protocol. Environmental Evidence. 3:7.
• Fabrick, J.A., Ponnuraj, J., Singh, A., Tanwar, R.K., Unnithan, G., Yelich, A.J., Li, X., Carriere, Y., Tabashnik, B.E. 2014. Alternative splicing and highly variable cadherin transcripts associated with field-evolved resistance of pink bollworm to Bt cotton in India. PLoS One. 9(5):e97900.
• Brent, C.S., Hull, J.J. 2014. Characterization of male-derived factors inhibiting female sexual receptivity in Lygus hesperus. Journal of Insect Physiology. 60:104-110.
• Byers, J.A. 2013. Modeling and regression analysis of semiochemical dose- response curves of insect antennal reception and behavior. Journal of Chemical Ecology. 39(8):1081-1089.
• Byers, J.A., Fefer, D., Levi-Zada, A. 2013. Sex pheromone component ratios and mating isolation among three lygus plant-bug species of North America. Naturwissenschaften. 12:1115-1123.
• Kawai, T., Nagata, K., Guo, L., Liu, D., Suzuki, T., Katayama, Y., Hayakawa, K., Lee, J., Nagamine, T., Hull, J.J., Matsumoto, S., Nagasawa, H., Tanokura, M. 2014. Identification of functionally important residues in the silkmoth pheromone biosynthesis-activating neuropeptide receptor, an insect ortholog of the vertebrate Neuromedin U Receptor. Journal of Biological Chemistry. 27:19150-19163.
• Asiimwe, P., Naranjo, S.E., Ellsworth, P. 2014. Effects of irrigation regime on interactions between Lygus hesperus, insecticides and predators in cotton. Environmental Entomology. 43:263-273.
• Klick, J., Lee, J.C., Hagler, J.R., Bruck, D.J., Yang, W.Q. 2014. Evaluating Drosophila suzukii (Diptera: Drosophilidae) immunomarking for mark-capture research. Environmental Entomology. 152:31-41.
• Kumar, R., Tian, J.C., Naranjo, S.E., Shelton, A.M. 2014. Effects of Bt cotton on Thrips tabaci and its predator, Orius insidiosus. Journal of Economic Entomology. 107:927-932.
• Williams III, L.H., Hagler, J.R., Tonkel, K.C. 2013. Does dimethyl sulfoxide increase protein immunomarking efficiency for dispersal and predation studies? Entomologia Experimentalis et Applicata. 148:275-286.
• Castle, S.J., Merten, P., Prabhaker, N. 2013. Comparative susceptibility of bemisia tabaci to imidacloprid in field- and laboratory-based bioassays. Pest Management Science. 2:773-780.
• Luo, S., Naranjo, S.E., Wu, K. 2013. Biological control of cotton pests in China. Biological Control. 68:6-14.
• Naranjo, S.E., Tian, J., Wang, X., Long, L., Romeis, J., Hellmich, R., Shelton, A. 2014. Eliminating host-mediated effects demonstrates Bt maize producing Cry1F has no adverse effects on the parasitoid Cotesia marginiventris. Transgenic Research. 23:257-264.
• Penick, C.A., Brent, C.S., Dolezal, K., Liebig, J. 2014. Neurohormonal changes associated with ritualized combat and the formation of a reproductive hierarchy in the ant Harpegnathos saltator. Journal of Experimental and Environmental Biology. 217:1496-1503.
• Byers, J.A., Birgersson, G., Francke, W. 2013. Aggregation pheromones of bark beetles, pityogenes quadridens and P. bidentatus, colonizing scotch pine: olfactory avoidance of interspecific competition. Chemoecology. 4:251-261.

Progress 10/01/12 to 09/30/13

Outputs
Progress Report Objectives (from AD-416): Develop knowledge and control tactics based on the physiology, biochemistry, genetics and vector-pathogen interactions of insect pests. Characterize and exploit interactions among plants, insect pests and natural enemies; investigate the role of arthropod predators and trophic interactions for improved biological control. Characterize flight behavior and dispersal of insect pests and natural enemies; elucidate relationships among landscape structure, pest and natural enemy biology and dispersal behavior. Refine sampling strategies for insect pests and their associated natural enemies; develop and refine economic thresholds for sucking pests in cotton that incorporate biological control potential; support post-eradication detection of pink bollworm populations. Refine insecticide-based management strategies; characterize factors influencing resistance to chemical insecticides and insecticidal proteins in transgenic crops; evaluate insecticide selectivity; support post- eradication pink bollworm resistance monitoring in Bt cotton. Approach (from AD-416): Research will build a solid foundation of fundamental tactics for avoiding pest problems and will strengthen prescriptive pest control through refinement of monitoring, decision aids and effective treatment options. Research will explore and exploit the molecular and chemical basis of male-derived factors on female mating inhibition and hormonal factors regulating reproduction and diapause in Lygus. hesperus, the molecular basis of water channel proteins in Bemisia tabaci, the impact of plant virus and plant allelochemical mediated changes on B. tabaci fitness and insecticide resistance, respectively, and the molecular basis of Bt resistance in Pectinophora gossypiella. Further research will exploit semiochemicals and tri-trophic interactions for enhanced biological control, and identify insect and plant based semiochemicals enabling mating disruption and improved monitoring of B. tabaci and L. hesperus. Flight behavior and inter- and intra-crop dispersal of L. hesperus, and source-sink relationships for arthropod predators inhabiting the agro-ecosystem will be quantified, facilitating IPM at the landscape scale. Selective insecticides and improved decision aids that account for natural enemy abundance will be evaluated and developed for B. tabaci in cotton. Research will further support P. gossypiella post- eradication efforts through refinement of pheromone-based monitoring systems and detection of resistance to Bt cotton. Replaces 5347-22620-017- 00D, 5347-22620-018-00D and 5347-22620-020-00D (10/10). Studies of plant bugs (Lygus) identified a new compound transferred from male to female during mating. This compound initially enhances inhibition of mating, but a breakdown product promotes mating. Synthetic versions of male-derived chemicals influenced mating behaviors in assays. Analyses of Lygus male sexual glands showed an increase in the numbers of genes expressed following mating. A Lygus protein receptor similar to those that regulate mating in other species was identified and characterized. Chemicals that promote egg laying but do not influence mating, were identified from brains of Lygus females. The diapause response of Lygus to different daylengths was defined and validation was initiated. Sex pheromones of three Lygus pest species were characterized and assayed. Lygus odorant binding proteins, essential for chemical communications, were analyzed but initial efforts at biochemical interference were inconclusive. The number of known functional aquaporins (proteins controlling internal water balance) was increased to five for Lygus and to seven for the sweetpotato whitefly, which increases the potential for genetic or biochemical-based controls. Botanical extracts influenced aquaporin function in assays, and were insecticidal when fed to the insects. Studies of the whitefly indicated the production of specific detoxification enzymes varied with exposure to different hosts. These results begin to elucidate the complex physiological relationships that must be understood to develop novel biochemically- or ecologically-based management approaches for Lygus and whitefly. Selection experiments produced a new strain of pink bollworm that is highly resistant to the two transgenic bacterial toxins used world-wide in commercial cotton, and the inheritance patterns of this resistance were elucidated. Analyses of pink bollworm from India, which are resistant to the most common transgenic toxin in cotton (Cry1Ac) indicated novel changes to a cell adhesion protein (cadherin). The changes differ from those in the modified cadherin of resistant pink bollworm selected in the laboratory. These results implicate the cadherins as a critically important source of resistance in pink bollworm, and are important in developing strategies to avoid or monitor resistance in the field. Protein markers used to study insect dispersal were improved, and movement patterns of Lygus and natural enemies within cotton were examined in the field. A new insect sampling method utilizing a rapid knockdown insecticide was evaluated. Studies of predator gut contents were conducted to distinguish cannibalism and scavenging from predation. Field studies of biological control-based thresholds for sweetpotato whitefly evaluated use of predator-prey ratios as an addendum to standard thresholds based on whitefly numbers only. Field surveys examined the pest and beneficial arthropod complexes associated with guayule seedlings. Better understanding of intra- and inter-crop diversity, population levels, and dispersion patterns of pests and their natural enemies is essential to successful integration of new management tactics into production systems. Accomplishments 01 An adult transcriptome for the western tarnished plant bug, Lygus hesperus. The western tarnished plant bug is an important crop pest in the western United States for which almost no molecular genetics information exists. ARS scientists at the Arid-Land Agricultural Research Center, Maricopa, Arizona, used next-generation sequencing to construct an adult Lygus transcriptome, which represents a record of gene expression. Compared with better-studied insects, many of the sequences were unique to Lygus. Intriguingly, compared with other insects a higher percentage of sequences were associated with antioxidant activity, which may be important to resisting biotic and abiotic stress. Exposure to high temperatures triggered increased expression of heat shock proteins that are thought to facilitate short- term adaptation to environmental stresses. This information serves as a broad baseline for future research, and will be essential to efforts to identify and develop new species-specific non-insecticidal controls. 02 Identification of Lygus plant bug sex pheromones. Lygus bugs (western tarnished plant bug, tarnished plant bug, and the pale legume bug) are important pests of many field, fruit, and vegetable crops. Elucidation of the chemicals emitted by females to attract males for mating (sex pheromones) has represented an intractable problem. An ARS scientist at the Arid-Land Agricultural Research Center, Maricopa, Arizona, and Israeli collaborators identified the chemical components of the respective Lygus sex pheromones and demonstrated attractiveness to males in field studies. These results provide the opportunity to develop pheromone lures and traps to permit improved population detection and monitoring. 03 Invasive species detection using traps and encounter-rate equations. Although the pink bollworm has been eradicated from several production regions of the United States, this critically important pest of cotton remains a major problem in other parts of the world. Sustainable eradication is dependent upon effective monitoring methods to detect re- invasion. ARS scientists at the Arid-Land Agricultural Research Center, Maricopa, Arizona, developed simulation methods to determine numbers and arrangements of pheromone traps to facilitate efficient monitoring. The methods use estimates of trap attractiveness combined with moth flight distance to instantaneously solve for trap number through modified encounter-rate equations. Estimates from the simulations will be useful to action agencies for optimizing trapping efforts for the pink bollworm. Furthermore, the simulation approach is adaptable to detection and monitoring of other invasive pests. 04 Transgenic crops have no effect on insect predators or parasitoids. Transgenic crops currently produce a number of target-specific insecticidal proteins from Bacillus thuringiensis (Bt) and have been cultivated on millions of hectares globally. Concerns about the ecological risk associated with these crops, specifically to nontarget organisms, continue to be raised. An ARS scientist from the Arid-Land Agricultural Research Center, Maricopa, Arizona, and researchers at Cornell University, ARS in Ames, Iowa, and Agroscope in Zurich, Switzerland, showed that the biology of two common predators (insidious flower bugs and big-eyed bugs) found in cotton and maize were not affected by chronic exposure to several Bt proteins via ingestion of Bt- resistant prey fed on Bt-maize and cotton over two generations. Similarly, the biology of a common parasitoid (Cotesia) of various caterpillar pests was not affected when exposed to Bt proteins through a Bt-resistant host feeding on Bt maize over multiple generations. Use of Bt-resistant prey and hosts instead of susceptible prey overcame a common problem with such assays by ensuring any observed effects were caused by the Bt toxin instead of by poor prey quality. Results are valuable to governmental authorities responsible for regulating transgenic crops, other scientists, and a general public concerned about the environmental effects of biotechnology. 05 Thermal ecology of the western tarnished plant bug (Lygus). Previous descriptions of Lygus development rates were simplistic and used antiquated experimental and statistical methodology. Because the adult reproductive diapause of Lygus in southern regions terminates in early winter, development and survival of immature stages and young adults under winter conditions may be as important to successful overwintering as the diapause. ARS scientists from the Arid-Land Agricultural Research Center, Maricopa, Arizona, and the Yakima Agricultural Research Laboratory, Wapato, Washington, defined the temperature dependence of development and survival for all Lygus life stages. Demonstration of extended development times and host-free survival under low-temperature conditions contradicts earlier reports that place ecological constraints on mechanisms of Lygus overwintering. Ecological interpretation of these results is consistent with field observations of overwintering populations, and quantitative models permit prediction of population phenology given appropriate meteorological inputs. These results will be indispensible to a more complete understanding of Lygus overwintering ecology, and provide important baseline information for ongoing examinations of the physiology and molecular biology of Lygus thermal ecology.

Impacts
(N/A)

Publications

• Penick, C.A., Trobaugh, B., Brent, C.S., Liebig, J. 2013. Head butting as an early indicator of reproductive disinhibition in the termite zootermopsis nevadensis. Journal of Insect Behavior. 26:23-24.
• Byers, J.A. (2012). Modelling female mating success during mass trapping and natural competitive attraction of searching males or females. Entomologia Experimentalis et Applicata. 145:228-237.
• Hartfelder, K., Bitondi, M., Brent, C.S., Guidugli-Lazzarini, K.R., Simoes, Z.L., Stabentheiner, A. 2013. Physiology and biochemistry of honey bees. In:Dietermann, V., Ellis, J.D., Neumann, P.,editors. The COLOSS BEEBOOK, Volume I: Standard methods for Apis mellifera research. South Glamorgan, United Kingdom: Ibra Publications.
• Spurgeon, D.W., Cooper, W.R. 2012. Disinfestation of Beauveria bassiana from adult Lygus hesperus using ultraviolet-C radiation. Southwest Entomology. 37(4):449-457.
• Hull, J.J., Geib, S.M., Fabrick, J.A., Brent, C.S. 2013. Sequencing and de novo assembly of the western tarnished plant bug (Lygus hesperus) transcriptome. PLoS One. 8:1.
• Byers, J.A. 2012. Ecological interactions of bark beetles with host trees. Psyche. 2012:1-3.
• Asiimwe, P., S.E. Naranjo & P.C. Ellsworth. 2013. Relative influence of plant quality and natural enemies on the seasonal dynamics of bemisia tabaci (Hemiptera: Aleyrodidae) in cotton. Journal of Economic Entomology. 106:1260-1273.
• Crowder, D., Ellsworth, P., Naranjo, S.E., Tabashnik, B., Carriere, Y. 2013. Modeling resistance to juvenile hormone analogs: linking evolution, ecology and management. In: Devillers, James, editor. Juvenile Hormones and Juvenoids. Boca Raton, FL: CRC Press. p. 99-126.
• Tian, J.C., Wang, X.P., Long, L.P., Romeis, J., Naranjo, S.E., Hellmich II, R.L., Wang, P., Earle, E.D., Shelton, A.M. 2013. Bt crops producing Cry1Ac, Cry2Ab and Cry1F do not harm the green lacewing, chrysoperla rufilabris. PLoS One. 8(3):e60125.
• Han, B., Zhang, Q.H., Byers, J.A. 2012. Attraction of the tea aphid, Toxoptera aurantii, to combinations of volatiles and colors related to tea plants. Entomologia Experimentalis et Applicata. 144:258-269.
• Sivakoff, F.S., Rosenheim, J.A., Hagler, J.R. (2012). Relative dispersal ability of a key agricultural pest and its predators in an annual agroecosystem. Biological Control. 63:296-303
• Spurgeon, D.W., Cooper, W.R. 2012. Temperature-dependent reproductive development of Lygus hesperus (Hemiptera: Miridae). Environmental Entomology. 41(4):941-949.
• Hull, J.J., Hoffmann, E.J., Perera, O.P., Snodgrass, G.L. 2012. Identification of the western tarnished plant bug (lygus hesperus) olfactory co-receptor orco: expression profile and confirmation of atypical membrane topology. Archives of Insect Biochemistry and Physiology. 81(4):179-198.
• Cooper, W.R., Spurgeon, D.W. 2013. Temperature-dependent egg development of Lygus hesperus (Hemiptera: Miridae). Journal of Economic Entomology. 106(1):124-130.
• Spurgeon, D.W., Cooper, W.R. 2013. Sweepnet captures of Lygus hesperus (Hemiptera:Miridae) adult genders and age-classes in cotton. Journal of Entomological Science. 48(3):195-205.
• Cooper, W.R., Spurgeon, D.W. 2013. Response by Lygus hesperus (Hemiptera: Miridae) adults to salivary preconditioning of cotton squares. Journal of Entomological Science. 48(3):261-264.
• Kelly, J.L., Hagler, J.R., Kaplan, I. 2012. Employing immunomarkers to track dispersal and trophic relationships of piercing-sucking predator, Podisus maculiventris (Hemiptera: Pentatomidae). Environmental Entomology. 41(6):1527-1533.
• Hagler, J.R., Blackmer, F. 2013. Identifying inter-and intraguild predator feeding activity of an anthropod predator assemblage. Ecological Entomology. 38:258-271.
• Hagler, J.R., Blackmer, F., Krugner, R., Groves, R.L., Morse, J.G., Johnson, M.W. 2013. Gut content examination of the citrus predator assemblage for the presence of Homalodisca vitripennis remains. Biocontrol. 58:341-349.
• Swezey, S.L., Nieto, D.J., Hagler, J.R., Pickett, C.H., Bryer, J.A., Machtley, S.A. 2013. Dispersion, distribution and movement of Lygus spp. (Hemiptera:Miridae)in trap-cropped organic strawberries. Environmental Entomology. 42(4):770-778.
• Castle, S.J., Prabhaker, N. 2013. Monitoring changes in bemisia tabaci susceptibility to neonicotinoid insecticides in Arizona and California. Journal of Economic Entomology. 106(3):1404-1413.
• Krugner, R., Hagler, J.R., Groves, R.L., Sisterson, M.S., Morse, J.G., Johnson, M.W. 2012. Plant water stress effects on the net dispersal rate of the insect vector Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) and movement of its egg parasitoid, Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae). Environmental Entomology. 41(6):1279- 1289.
• Brent, C.S., Klok, C.J., Naranjo, S.E. 2013. Effect of diapause status and gender on activity, metabolism and starvation resistance in the plant bug Lygus hesperus Knight. Entomologia Experimentalis et Applicata. 148(2):152- 160.
• Tian, J., Collins, H.L., Romeis, J., Naranjo, S.E., Hellmich II, R.L., Shelton, A.M. 2012. Using field-evolved resistance to Cry1F maize in a lepidopteran pest to demonstrate no adverse effects of Cry1F on one of its major predators. Transgenic Research. 21(6):1303-1310.
• Shelton, A., Naranjo, S.E., Romeis, J., Hellmich II, R.L. 2012. Errors in logic and statistics plague a meta-analysis. Environmental Entomology. 41:1047-1049.
• Dai, H., Hiromasa, Y., Takahashi, D., Vandervelde, D., Fabrick, J.A., Kanost, M.R., Krishnamoorthi, R. (2013). beta-1,3-Glucan recognition by an insect pathogen recognition domain causes self-association of protein: carbohydrate complex. Biochemistry, 52(1):161-170.

Progress 10/01/11 to 09/30/12

Outputs
Progress Report Objectives (from AD-416): Develop knowledge and control tactics based on the physiology, biochemistry, genetics and vector-pathogen interactions of insect pests. Characterize and exploit interactions among plants, insect pests and natural enemies; investigate the role of arthropod predators and trophic interactions for improved biological control. Characterize flight behavior and dispersal of insect pests and natural enemies; elucidate relationships among landscape structure, pest and natural enemy biology and dispersal behavior. Refine sampling strategies for insect pests and their associated natural enemies; develop and refine economic thresholds for sucking pests in cotton that incorporate biological control potential; support post-eradication detection of pink bollworm populations. Refine insecticide-based management strategies; characterize factors influencing resistance to chemical insecticides and insecticidal proteins in transgenic crops; evaluate insecticide selectivity; support post- eradication pink bollworm resistance monitoring in Bt cotton. Approach (from AD-416): Research will build a solid foundation of fundamental tactics for avoiding pest problems and will strengthen prescriptive pest control through refinement of monitoring, decision aids and effective treatment options. Research will explore and exploit the molecular and chemical basis of male-derived factors on female mating inhibition and hormonal factors regulating reproduction and diapause in Lygus. hesperus, the molecular basis of water channel proteins in Bemisia tabaci, the impact of plant virus and plant allelochemical mediated changes on B. tabaci fitness and insecticide resistance, respectively, and the molecular basis of Bt resistance in Pectinophora gossypiella. Further research will exploit semiochemicals and tri-trophic interactions for enhanced biological control, and identify insect and plant based semiochemicals enabling mating disruption and improved monitoring of B. tabaci and L. hesperus. Flight behavior and inter- and intra-crop dispersal of L. hesperus, and source-sink relationships for arthropod predators inhabiting the agro-ecosystem will be quantified, facilitating IPM at the landscape scale. Selective insecticides and improved decision aids that account for natural enemy abundance will be evaluated and developed for B. tabaci in cotton. Research will further support P. gossypiella post- eradication efforts through refinement of pheromone-based monitoring systems and detection of resistance to Bt cotton. Studies of Lygus flight after feeding on cotton, alfalfa, guayule, camelina, and lesquerella were initiated. Understanding host effects on flight may provide insights into Lygus movement among crops. A compound transferred by male lygus during mating that makes females unattractive to other males was shown to change chemically over time, restoring female attractiveness. Five odorant binding proteins were identified from Lygus antennae, and additional components involved in communication are sought. Understanding chemical communications may facilitate mating disruption or other control methods. Lygus overwinter in a state of reduced metabolism (diapause). Studies of the hormonal control of diapause continued. Survival studies showed that diapausing Lygus tolerated environmental stresses better than reproductive Lygus. About 36,000 DNA sequences from Lygus were generated and a subset may be involved in mediation of thermal stress. These results contribute to efforts to develop ecologically-based management strategies for Lygus. Efforts to optimize inexpensive protein markers (egg white, milk protein, soy protein) for studying insect dispersal revealed marker concentrations for effective marking of insects, and indicated a small incidence of inter-insect marker transfer. These results reduce cost and improve effectiveness of mark-recapture studies. Progress was made in developing biological control based thresholds for sweetpotato whitefly in cotton using selective and non-selective insecticides to manipulate pest and natural enemy populations. Whitefly populations were larger in cotton infected with cotton leaf crumple virus than in uninfected cotton, indicating virus infection benefits the whitefly. Studies were initiated to examine effects of prior experience and host plant on parasite effectiveness against the whitefly. Assays showed that whitefly resistance to a commonly used material (imidacloprid) was higher than to three other neonicotinoid insecticides. Studies of effects of plant defensive compounds on whiteflies were started. Field studies showed that Lygus, big-eyed bugs, and collops beetles fed on whitefly, but Lygus and big-eyed bugs also fed on each other. Function of a water channel protein in the whitefly gut, BtAQP1, was confirmed. Treatments to interfere with this protein have yet to affect whitefly fitness. Better methodology, or identification of additional channel proteins, is needed to advance this approach to whitefly control. Collectively, these results shed light on factors controlling whitefly populations, which is essential to improved management. Studies of pink bollworm resistance to Bt cotton revealed a new resistance gene resulting from a mutation. It is the fourth cadherin gene linked to resistance, suggesting the cadherin gene is a primary source of Bt resistance. Examination of field-collected Bt resistant pink bollworm indicated the resistance was from a cadherin gene modified by a mobile DNA element (jumping gene). Models of invasive species detection were developed based on pink bollworm. Progress in understanding Bt resistance and monitoring pink bollworm resistance is critical to eradication efforts. Accomplishments 01 Optimized protein marking for arthropod dispersal research. The protein marking procedure is a powerful method for marking insects for ecologica studies. However, first-generation protein marks consist of vertebrate I proteins, the expense of which has limited their use. In studies of alternative marking materials including egg white (albumin), milk protei (casein), and soy protein (trypsin), an ARS scientist from the Arid-Land Agricultural Research Center, Maricopa, AZ, identified substitutes more economical than, and in some cases superior to, the IgG proteins. Insect retention of the markers was compared to rabbit IgG, and application rat necessary to mark >90% of the resident arthropod population were determined. Application of these alternative markers to ecological questions facilitates large-scale studies that were previously prohibitively expensive, and increases the availability of this marking methodology to a wider range of potential users. 02 Bt resistance genes in pink bollworm. Transgenic Bt cotton, cotton that makes insecticidal proteins from the bacterium Bacillus thuringiensis, i an essential tool of the Pink Bollworm Eradication Program. Genes conferring resistance to Bt cotton are known to occur in the pink bollwo and although control failures have not been observed in the U.S., field populations of Bt-resistant pink bollworm have appeared in other countri An ARS scientist from the Arid-Land Agricultural Research Center, Maricopa, AZ, and collaborators at the University of Arizona, showed tha resistance to Bt cotton is genetically linked with changes in the pink bollworm cadherin gene, and that one such cadherin mutation involved an insertion of a mobile DNA element or �jumping gene.� In addition, the AR scientist identified a new resistance gene from the pink bollworm, bringing the total to four known cadherin mutations genetically linked t Bt resistance. These results implicate changes to the cadherin gene as t predominant mechanism of pink bollworm resistance to Bt cotton, and accentuate the importance of cadherin-based resistance monitoring to preservation of this critically important control technology. 03 An integrated approach to insecticide resistance monitoring. Pest resistance to insecticides remains a major concern to agricultural producers worldwide. Insecticide resistance monitoring programs generall rely on laboratory bioassays to detect changes in susceptibility of targ pest populations, but results of these assays are often poor indicators insecticide field performance. ARS scientists from the Arid-Land Agricultural Research Center, Maricopa, AZ, conducted parallel laborator and field-based bioassays on adults of the sweetpotato whitefly, Bemisia tabaci, and compared the results to control levels achieved in cantaloup treated with the insecticide imidacloprid. Whitefly mortality was much higher in the laboratory systemic uptake bioassay compared with the fiel based bioassay, whereas control obtained in the cantaloupes was excellen because the insecticide prevented establishment of immature whiteflies i the crop. These results underscore the importance of utilizing a combination of bioassay and field efficacy approaches in support of regulatory and control program decisions regarding insecticide performan 04 Transgenic crop has no effect on important insect predator. Transgenic crops producing the target-specific insecticidal proteins of Bacillus thuringiensis (Bt) have been widely adopted and cultivated on millions o hectares globally. However, there remain concerns about the ecological risk associated with these crops, specifically to non-target organisms. ARS scientists from the Arid-Land Agricultural Research Center, Maricopa AZ, and researchers at Cornell University, ARS in Ames, IA, and Agroscop in Zurich, Switzerland showed that the biology of a common predatory lad beetle was not affected by ingestion of Bt-resistant prey fed on Bt-maiz over two generations. Use of Bt-resistant prey instead of susceptible pr overcame a common problem with such assays by ensuring any observed effects were caused by the Bt toxin instead of by poor prey quality. Results are valuable to governmental authorities responsible for regulating transgenic crops, other scientists, and a general public concerned about the environmental effects of biotechnology. 05 Comparative impacts of plant quality and natural enemies on pest dynamic in cotton. The sweetpotato whitefly, Bemisia tabaci, and the western tarnished plant bug, Lygus hesperus, are key pests of cotton and other crops in the western U.S. ARS scientists from the Arid-Land Agricultural Research Center, Maricopa, AZ, and collaborators from the University of Arizona demonstrated differential influences of plant quality (manipulat by varying water supplied by irrigation) and natural enemies on these tw pest species. Crop water stress reduced Lygus bug populations, compared with unstressed cotton, regardless of insecticide treatments. In contras whitefly populations were more influenced by insecticide-induced disruption of generalist predators than by variations in plant quality. For both pests, preservation of natural enemies through use of selective insecticides provided better pest control and enhanced yields compared with broad-spectrum insecticides. These results provide producers information that is essential to conservation of natural enemies, and to improve the efficiency of pest and crop management efforts. 06 A molecular approach to studying arthropod predation. Understanding predator-prey interactions of the arthropod predator community in any given ecosystem is essential for pinpointing the ecosystem services provided by natural enemies. An ARS scientist from the Arid-Land Agricultural Research Center, Maricopa, AZ, developed, optimized, and utilized a suite of prey-specific DNA-based assays to analyze the gut contents of the cotton predator community. The targeted insects included an herbivore pest (sweetpotato whitefly), a strict predator (collops beetle), an omnivorous pest (lygus bug), and an omnivorous predator (big eyed bug). Gut analyses showed that the strict predator and both omnivor fed substantially on whiteflies. However, the two omnivores also fed on each other, but rarely fed on the collops beetle. The gut assays further revealed that the targeted pests (whitefly and lygus) were more frequent eaten by insect predators than by spiders, whereas the two beneficial species (big-eyed bug and collops beetle) were fed upon by both insect a spider predators. This study serves as a model to demonstrate the utilit of DNA-based methods in elucidating complex food web interactions.

Impacts
(N/A)

Publications

• Xianchun, L., Degain, B.A., Harpold, V.S., Marcon, P.G., Nichols, R.L., Fournier, A.J., Naranjo, S.E., Palumbo, J.C., Ellsworth, P.C. 2012. Baseline Susceptibilities of B- and Q-biotype Bemisia tabaci to anthranilic diamides. Pest Management Science. 68:83-91.
• Fabrick, J.A., Mathew, L.G., Tabashnik, B.E., Li, X. 2011. An intact CR1 retrotranspon is linked with BT resistance in the pink bollworm, Pectinophora gossypiella. Insect Molecular Biology. 20(5),651-665.
• Rosengaus, R.B., James, L., Hartke, T.R., Brent, C.S. 2011. Mate preference and disease risk in Zootermopsis angusticollis (Isoptera:Termopsidae. Environmental Entomology. 40(6):1554-1565.
• Naranjo, S.E., Ellsworth, P.C., Dierig, D.A. 2011. Impact of Lygus spp. (Hemiptera: Miridae) on damage, yield and quality of lesquerella (Physaria fendleri), a potential new oil-seed crop. Journal of Economic Entomology. 104: 1575-1583.
• Dolezal, A.G., Brent, C.S., Holldobler, B., Amdam, G. 2012. Worker division of labor and endocrine physiology are associated in the harvester ant, Pogonomyrmex californicus. Journal of Experimental Biology Online. 215:454-460.
• Irvin, N.A., Hagler, J.R., Hoddle, M.S. 2012. Laboratory investigation of triple marking the parasitoid Gonatocerus ashmeadi (Hymenoptera: Mymaridae) with a fluorescent dye and two animal proteins. Entomologia Experimentalis et Applicata. 143:1-12.
• Naranjo, S.E., Stefanek, M.A. 2012. Feeding Behavior of a Potential Insect Pest, Lygus hesperus, on Four New Industrial Crops for the Arid Southwestern USA.. Industrial Crops and Products. 37:358-361.
• Lu, R.C., Wang, H.B., Zhang, Z., Byers, J.A., Jin, Y.J., Wen, H.F. 2012. Coexistence and competition between Tomicus Yunnanensis and T. minor (Coleoptera: Scolytidae) in yunnan pine. Psyche. vol.2012,pp.1-6.
• Fabrick, J.A., Tabashnik, B.E. 2012. Similar genetic basis of resistance to bt toxin cry1ac in boll-selected and diet-selected strains of pink bollworm. PLoS One. doi:10.1371/journal.pone.0035658.
• Gao, Y., Jurat-Fuentes, J., Oppert, B.S., Fabrick, J.A., Lui, C.A., Gao, J. , Lei, Z. 2011. Increased toxicity of Bacillus thuringiensis Cry3Aa against Crioceris quatuordecimpunctata, Phaedon brassicae and Colaphellus bowringi by a Tenebrio molitor cadherin fragment. Pest Management Science. 67(9): 1076-1081.
• Hagler, J.R. 2011. An immunological approach to quantify consumption of protein-tagged Lygus hesperus by the entire cotton predator assemblage. Biological Control. 58 (2011) 337�345.
• Brent, C.S., Byers, J.A. 2011. Female attractiveness modulated by a male- derived antiaphrodisiac pheromone in a plant bug. Animal Behaviour. doi:10. 1016/j.anbehav.2011.08.010..
• Carriere, Y., Goddell, P., Ellers-Kirk, C., Dutilleul, P., Naranjo, S.E., Ellsworth, P.E. 2012. Effects of local and landscape factors on population dynamics of a cotton pest.. PLoS One. doi:10.1371/journal.pone.0039862.
• Booth, W., Brent, C.S., Calleri, D.V., Rosengaus, R.B., Traniello, J.F., Vargo, E.L. 2011. Population genetic structure and colony breeding system in dampwood termites (Zootermopsis angusticollis and Z. nevadensis nuttingi). Insectes Sociaux. 59:127-137.
• Byers, J.A. 2011. Analysis of vertical distributions and effective flight layers of insects: three-dimensional simulation of flying insects and catch at trap heights. Environmental Entomology. 40(5):1210-1222.
• Byers, J.A. 2012. Estimating insect flight densities from sticky trap catches and effective flight layers. Environmental Entomology. 38(5):592- 601.
• Byers, J.A. 2012. A genetic model of evolution of host-mate attraction and nonhost repulsion in a bark beetle Pityogenes bidentatus. Psyche. 2012:1- 10.
• Byers, J.A., Birgersson, G. 2012. Host-tree monoterpenes and biosynthesis of aggregation pheromones in the bark beetle Ips paraconfusus. Psyche. 2012:1-10.
• Byers, J.A. 2012. Bark beetles, Pityogenes bidentatus, responding to aggregation pheromone avoid conifer monoterpene odors when flying but not when walking. Psyche. 2012:1-10.
• Carri�re, Y., C.Ellers-Kirk, K. Hartfield, G. Larocque, B. Degain, P. Dutilleul, T. J. Dennehy, S. E. March, D. W. Crowder, X. Li, P. C. Ellsworth, S. E. Naranjo, J. C. Palumbo, A. Fournier, L. Antilla & B. E. Tabashnik. 2012. Large-scale, spatially explicit test of the refuge strategy for delaying insecticide resistance. Proc. Nat. Acad. Sci. (USA) 109:775-780.
• Castle, S.J., Palumbo, J.C. 2011. Cantaloupe Insects: Ecology and Control. Encyclopedia of Pest Management. 10.1081/E-EPM.
• Hagler, J.R., Mueller, S., Teuber, L.R., Van Deynze, A., Martin, J. 2011. A method for distinctly marking honey bees, Apis mellifera originating from multiple apiary locations. Journal of Insect Science. 11:143.
• Hagler, J.R., Mueller, S., Teuber, L.R., Machtley, S.A., Deynze, A.V. 2011. Foraging range of honey bees, Apis mellifera, in alfalfa seed production fields. Journal of Insect Science. 11:144.
• Helms Cahan, S., Graves, C.J., Brent, C.S. 2011. Intergenerational effect of juvenile hormone on offspring in Pogonomyrmex harvester ants. Journal of Comparative Physiology. 181(8):991.
• Hoffmann, E.J., Castle, S.J. 2012. Imidacloprid in Melon Guttation Fluid: A Mode of Exposure for Pest and Beneficial Organisms. Journal of Economic Entomology. 105(1):67-71.
• Lee, J.M., Hull, J.J., Kawai, T., Goto, C., Kurihara, M., Tanokura, Y., Nagata, K., Nagasawa, H., Matsumoto, S. 2012. Re-evaluation of the PBAN receptor (PBANR) molecule: Characterization of PBANR variants expressed in the pheromone glands of several moth species. Frontiers in Endocrinology. Vol 3,article 56,pp 1-8.
• Lee, J.M., Hull, J.J., Kawai, T., Kurihara, M., Tanokura, M., Nagata, K., Nagasawa, H., Matsumoto, S. 2012. Establishment of a stable Sf9 transformation expression system for functional evaluation of PBAN receptor (PBANR) variants. Frontiers in Endocrinology. Vol 3,article 56, pp 1-8.
• Lu, R.C., Wang, H.B., Zhang, Z., Byers, J.A., Jin, Y.J., Wen, H.F. 2012. Attraction of Tomicus yunnanensis (Coleoptera: Scolytidae) to Yunnan pine logs with and without periderm or phloem: an effective monitoring bait. Psyche. ID 794683. 2012:1-5.
• Oppert, B.S., Dowd, S.E., Bouffard, P., Li, L., Conesa, A., Lorenzen, M.D., Toutges, M., Marshall, J., Huestis, D., Fabrick, J.A., Oppert, C., Jurat- Fuentes, J. 2012. Transcriptome profiling of the intoxication response of Tenebrio molitor larvae to Bacillus thuringiensis Cry3Aa protoxin. PLoS One. 7(4): e34624. 12pp. Available:
• Penick, C.A., Liebig, J., Brent, C.S. 2011. Reproduction, dominance, and caste: endocrine profiles of queens and workers of the ant Harpegnathos saltator. Journal of Comparative Physiology. 197(11):1063-1071.
• Rodriguez-Saona, C., Byers, J.A., Schiffhauer, D. 2012. Effect of trap color and height on captures of blunt-nosed and sharp-nosed leafhoppers (Hemiptera: Cicadellidae) and non-target arthropods in cranberry bogs. Journal of Applied Entomology. 40:132-144.
• Florence, T., Yun-Gen, M., Bong-Hee, S., Young-Soo, K., Hull, J.J., Fraser, M.J., Lewis, R.V., Jarvis, D.L. 2012. Silkworms transformed with chimeric silkworm/spider silk genes spin composite silk fibers with improved mechanical properties. Proceedings of the National Academy of Sciences. 109(3):923-928.
• Wang, Y., Brent, C.S., Fennern, E., Amdam, G.V. 2012. Gustatory perception and fat body energy metabolism are jointly affected by vitellogenin and juvenile hormone in honey bees. PLoS Genetics. 8(6):e1002779.
• Williams III, L.H., Hagler, J.R., Tonkel, K.C. 2011. Retention of immunolabels by Diorhabda carinulata (Coleoptera: Chrysomelidae), a biological control agent of saltcedar. Entomologia Experimentalis et Applicata. 141:154-162.
• Slosky, L.M., Hoffmann, E.J., Hagler, J.R. 2012. A comparative study of the retention and lethality of the first and second generation arthropod protein markers. Entomologia Experimentalis et Applicata. 144(2):165-171.

Progress 10/01/10 to 09/30/11

Outputs
Progress Report Objectives (from AD-416) Develop knowledge and control tactics based on the physiology, biochemistry, genetics and vector-pathogen interactions of insect pests. Characterize and exploit interactions among plants, insect pests and natural enemies; investigate the role of arthropod predators and trophic interactions for improved biological control. Characterize flight behavior and dispersal of insect pests and natural enemies; elucidate relationships among landscape structure, pest and natural enemy biology and dispersal behavior. Refine sampling strategies for insect pests and their associated natural enemies; develop and refine economic thresholds for sucking pests in cotton that incorporate biological control potential; support post-eradication detection of pink bollworm populations. Refine insecticide-based management strategies; characterize factors influencing resistance to chemical insecticides and insecticidal proteins in transgenic crops; evaluate insecticide selectivity; support post- eradication pink bollworm resistance monitoring in Bt cotton. Approach (from AD-416) Research will build a solid foundation of fundamental tactics for avoiding pest problems and will strengthen prescriptive pest control through refinement of monitoring, decision aids and effective treatment options. Research will explore and exploit the molecular and chemical basis of male-derived factors on female mating inhibition and hormonal factors regulating reproduction and diapause in Lygus. hesperus, the molecular basis of water channel proteins in Bemisia tabaci, the impact of plant virus and plant allelochemical mediated changes on B. tabaci fitness and insecticide resistance, respectively, and the molecular basis of Bt resistance in Pectinophora gossypiella. Further research will exploit semiochemicals and tri-trophic interactions for enhanced biological control, and identify insect and plant based semiochemicals enabling mating disruption and improved monitoring of B. tabaci and L. hesperus. Flight behavior and inter- and intra-crop dispersal of L. hesperus, and source-sink relationships for arthropod predators inhabiting the agro-ecosystem will be quantified, facilitating IPM at the landscape scale. Selective insecticides and improved decision aids that account for natural enemy abundance will be evaluated and developed for B. tabaci in cotton. Research will further support P. gossypiella post- eradication efforts through refinement of pheromone-based monitoring systems and detection of resistance to Bt cotton. Replaces 5347-22620-017- 00D, 5347-22620-018-00D and 5347-22620-020-00D (10/10). Plant bugs, Lygus spp., readily feed on the reproductive tissue of 4 new industrial crops (camelina, guayule, lesquerella, vernonia). Behavior did not differ among life stages or sexes and insects fed less on camelina. Flight assays for Lygus adults at high (30C) and low (16C) temperatures show the insect has a narrow physiological range for flight. Research determined Lygus bug hormonal dynamics regulating sexual maturation, gametogenesis and metabolism. The source and nature of Lygus male derived compounds that regulate female reproductive behavior were explored. The properties and composition of a Lygus male-derived antiaphrodisiac regulating female attractiveness was elucidated. Progress was made in understanding the metabolic rate and activity levels of diapausing and non-diapausing males and females and the efficacy of an external color classification system for non-invasively identifying the diapause status. Lygus bug odor receptors similar to the Drosophia sex peptide receptor and odorant receptor were identified. In addition, 39 Lygus odorant binding proteins were identified with many selectively expressed in the adult antennae and 1 up-regulated in response to female mating. These receptors are localized on the cell surface. The Lygus sex peptide receptor expression profile is consistent with a role in mediating sexual behavior. Research discovered a novel water channel protein from the Bemisia tabaci (whitefly) gut where it plays an important role in water balance. A whitefly strain discovered in 2004 from an Arizona retail store possessed high levels of resistance to insecticides and was confirmed as the first detection of the exotic Q biotype in the U.S. No Q biotype B. tabaci have ever been recovered from Arizona field crops indicating that the Q biotype may thus far be restricted to retail or wholesale ornamentals. Proteins are being used to mark insects for dispersal studies. Collaborative research is being conducted to monitor insect dispersal in conventional crops and biofuel crops. Protein markers are being applied with a broadcast sprayer. In turn, field-collected insects are examined for the presence of the marks. This technique provides a tool to mark insects over entire landscapes to study insect dispersal patterns. Studies were initiated to estimate the concentration of different marking materials that need to be applied in the field in order to mark a consistent proportion of the insect population and to estimate the rate of potential mark transfer during sampling operations. Landscape-scale spatial analyses are being conducted to estimate source and sink relationships for natural enemies of Lygus and whitefly in the cotton ecosystem. Studies were initiated to examine the efficacy of natural enemy attractants for improved biological control in cotton. Comparative honeybee colony fitness was examined in hives near imidacloprid-treated cantaloupes and hives near untreated cantaloupes to evaluate the potential link between neonicotinoid insecticide exposure and colony collapse disorder. Spirotetramat was superior to all other insecticide treatment regimens against vine mealybug infestations in table grapes. Accomplishments 01 Release of sterile insects suppresses resistance to Bt in transgenic Bt cotton. The introduction of Bt cotton - transgenic cotton that makes insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) - greatly reduced pink bollworm populations in Arizona. But the invasive moth remains one of the world�s most destructive cotton pests and lab tests and international field collections show that it can develop resistance to Bt in Bt cotton. To slow resistance by the pest, growers i Arizona had been required to set aside �refuges� of conventional cotton that promote survival of pink bollworm caterpillars susceptible to Bt. B due to the expense and crop losses associated with refuges, in 2006 the Environmental Protection Agency granted permission to dispense with refuges in favor of releasing sterile pink bollworms over Arizona�s cott fields. In this multi-agency cooperative project, ARS research scientist in Maricopa, AZ, and Parlier, CA, and scientists from the University of Arizona found for the first time that the release of sterile insects can be used to effectively suppress pest resistance to Bt in Bt cotton over very large area. This information benefits government, academic, and industry researchers as well as regulators and administrators of insect control and resistance monitoring programs and provides new information regarding possible benefits of large-scale sterile insect release. 02 Pollinator movement between conventional and genetically modified (GM) crops. One concern in deploying transgenic plants in the environment is the spread of transgenes to other related crops in the region through pollen flow. ARS research scientists at the Arid-Land Agricultural Research Center, Maricopa, AZ, and researchers at the University of California at Davis mass marked honey bees exiting from 112 colonies ove a five mile area in order to track pollinator movement between conventional and herbicide tolerant alfalfa. The honey bee dispersal dat along with alfalfa seed sampling data estimate gene spread via pollen (pollen mediated gene flow). The distances traveled by marked bees range from a minimum of 45 m to a maximum of 5,983 m, with an average flight distance of 800 m from their apiary of origin. Gene flow averaged 1.7% 50 m, 0.2% at 1600 m, and was not detectable at 8,050 m. These results a being utilized by seed certification agencies to develop isolation distances, and mapping and stewardship programs to be employed during th production of seed for markets that are sensitive to the presence of transgenic traits. The results are valuable to producers and regulators terms of understanding the required distances for isolating biotech and conventional seed alfalfa production. 03 Landscape level dynamics of plant bugs in cotton. Lygus bugs affect multiple crops in arid-land agricultural systems and are major pests of cotton in Western U.S. ARS research scientists from the Arid-Land Agricultural Research Center, Maricopa, AZ, and researchers at the University of Arizona and the University of California developed predictive methods for estimating Lygus abundance in specific cotton fields. Abundance in a given cotton field can be accurately predicted by knowing the area of cotton, uncultivated habitats and seed alfalfa withi 2.75m of the cotton field. This provides growers with valuable informati on how they can manipulate the planting of various crops on their farms and potentially cooperate with neighboring growers to reduce the impact pest insects regionally. 04 Flight behavior, metabolism and survivorship of lygus bugs. Lygus is a multicrop pest in the western USA, which may be more sensitive to contro measures when it is overwintering. To take advantage of any potential susceptibility, more information is needed about seasonal variation in movement and metabolism. ARS research scientists at the Arid-Land Agricultural Research Center in Maricopa, AZ, showed that diapause statu reduced flight activity of females but not males and that diapause increased survivorship in males but not females. These results benefit producers and pest managers in terms of understanding insect movement in the landscape during winter and spring when the pest is potentially easi to control. 05 Insecticide residues in plant guttation fluid. Identifying ways by whic insecticide exposure occurs in a crop environment is important not only for effective targeting of a pest insect, but also for conserving beneficial insects by limiting exposure to pollinators, predators and parasitoids. Imidacloprid is a neonicotinoid insecticide that is taken-u by roots and systemically distributed throughout treated plants, and thu is generally considered to be selectively toxic only to plant feeding insects. ARS research scientists at the Arid-Land Agricultural Research Center, Maricopa, AZ, recovered relatively high concentrations of imidacloprid in the guttation fluid on field grown cantaloupes that were soil-treated with imidacloprid. Honeybees and other beneficial insects commonly imbibe free sources of water such as guttation droplets on leaf margins and are potentially at risk where guttation occurrences are comm Awareness of this potential source of toxicity to honeybees could help growers mitigate exposure by altering the timing of imidacloprid applications in crops or by relying on alternative insecticides. 06 Methods for calculating optimal trap height for monitoring pest insects. The abundance of many pest insect populations is monitored by placement attractive traps with pheromone lures at the mean flight height of the particular pest. Over 60 previous studies have placed traps at several heights on a pole to catch insects at these heights above ground. Howeve most of these studies have not calculated the mean flight height of species in order to find the optimal trap height for monitoring. Researchers at the Arid-Land Agricultural Research Center, Maricopa, AZ, developed mathematical analysis methods to determine mean flight height and standard deviation from catch data on three or more trap placement heights for over 100 insect species reported in the literature - many pests of agriculture. Computer simulations verified the analysis methods which will allow future studies to accurately determine the optimal heig for monitoring traps that delineate pest population abundance and their distribution in the cropland. 07 Lygus impacts on the new oil-seed crop Lesquerella. Lygus bugs affect multiple crops in arid-land agricultural systems, including the new crop lesquerella that is being considered as a substitute for castor in production of industrial oils and resins. Researchers at the Arid-Land Agricultural Research Center, Maricopa, AZ, and the University of Arizon conducted long term field studies to quantify the impact of Lygus bugs o Lesquerella yield. Studies found no significant limits in seed yield or seed oil content when the crop is managed in an optimal fashion. Results will benefit growers in arid production regions who are considering Lesquerella as an alternative crop or a rotational crop in their production systems. 08 Diapause status affects external body color of Lygus. Elucidating the regulation of Lygus life cycles is essential for developing new approach for targeted control, but such research is constrained by a lack of clea external markers that can accurately and non-invasively differentiate between bugs in different metabolic and developmental states. ARS resear scientists at the Arid-Land Agricultural Research Center, Maricopa, AZ, showed that the extent and color of sub-cuticular fat creates distinct color variants that provides a non-invasive technique for quickly differentiating between diapausing (dormant) and non-diapausing individuals. Diapausers have a ventral abdomen that is light yellow to light green in color while non-diapausers have a dark green color. This color diagnostic will permit rapid assessment of field populations by growers and researchers, and will facilitate laboratory studies of development and reproduction regulation. 09 Development of an easy-to-use predator gut assay. The development of antibody and DNA probes for the study of predation is time consuming, costly, and may not be feasible for many biological control researchers. Researchers at the Arid-Land Agricultural Research Center, Maricopa, AZ, developed an easy, cost effective, and quantifiable molecular gut conten assay for studying predation on insect pests. Recent research has shown that this method is more accurate and reliable than DNA based gut conten assays. Predation rates on Lygus (a major pest) by the entire cotton predator complex were quantified using this method. This methodology provides a new tool for researchers to study many types of predator/prey interactions.

Impacts
(N/A)

Publications

• Salvucci, M.E., Barta, C., Byers, J.A., Canarini, A. 2010. Photosynthesis and assimilate partitioning between carbohydrates and isoprenoid products in vegetatively active and dormant guayule: physiological and environmental constraints on rubber accumulation in a semiarid shrub. Physiological Plantarum. 140:368-379.
• Brent,C.S., Spurgeon,D.W. 2011. Diapause response of laboratory reared and native lygus hesperus knight (Memiptera:Miridae). Environmental entomology. 40:455-461.
• Naranjo, S.E., Castle, S.J. 2010. Sequential sampling plans for estimating density of glassy-winged sharpshooter, homalodisca vitripennis (Hemiptera: Cicadellidae) on citrus. Crop Protection Journal. 29:1363-1370.
• Fabrick, J.A. 2010. Insights into the genetics and molecular mechanisms of pink bollworm resistance to cry toxins. Southwestern Entomologist.35:431- 435.
• Brent,C.S., Fasnacht,M.P., Judd,T.M. 2011. Post-mating enhancement of fecundity in females lygus hesperus. Physiological Entomology. 36:141-148.
• Byers,J.A., Zada,A. 2010. Individual variation of (S)-4-methyl-3-heptanone in heads of braconid wasp, Leiophron uniformis, and Pogonomyrmex ants indicates costs of semiochemical production. Chemoecology. 21:35-44.
• Dennehy,T.J., Degain,B.A., Harphold,V.S., Zaborac,M., Morin,S., Fabrick,J. A., Nichols, R.L., Brown, J.K., Byrne, F.J., Li, X. 2010. Extraordinary resistance to insecticides reveals exotic Q biotype of Bemisia tabaci. Journal of Economic Entomology. 103(6):2174-2186.
• Naranjo,S.E. 2011. Impact of Bt transgenic cotton on integrated pest management. Journal of Agricultural and Food Chemistry. 59:5842-5851.
• Prabhaker,N., Castle,S.J., Naranjo,S.E., Toscano,N., Morse,J. 2011. Compatibility of two systematic neonicotinoids, imidacloprid and thiamethoxam with various natural enemies of agricultural pests. Journal of Economic Entomology. 104:773-781.
• Richards, T.J., Ellsworth, P., Tronstad, R., Naranjo, S.E. 2010. Market- based instruments for optimal control of invasive insect species: B. tabaci in Arizona. Journal of Agricultural and Resource Economics. 35:349- 367.
• Sivakoff, F.S., Rosenheim, J.A., Hagler, J.R. 2011. Threshold choice and the analysis of protein marking data in long distance dispersal studies. Methods in Ecology and Evolution. 2:77�85.
• Tabashnik,B.E., Sisterson,M.S., Antilla,L., Liesner,L., Staten,R.T., Ellsworth, P.C., Fabrick,J.A., Yelich,A.J., Unnithan,G.C., Ellers-Kirk,C., Carriere,Y. 2010. Suppressing resistance to Bt cotton with sterile insect releases. Nature Biotechnology. 28(12):1304-1307.
• Zhang,Q., Ma,J., Byers,J.A., Klein,M.G., Luo,Y., Zhao,F., Yang,Q. 2010. Olfactory and visual responses of the long-legged chafer hoplia spectabilis medvedev (Coleoptera: Scarabaeidae) in Qinghai province, China. Pest Management Science. 67:162-169.
• Castle,S.J., Prabhaker,N. 2011. The challenge of green in a pesticide- dominant IPM World. pp.300-338. In green trends in insect control, Lopez, O, Fernandez Bolanos,J.(eds). Royal Society of Chemistry, Cambridge, UK.