Location: Pest Management and Biocontrol Research2011 Annual Report
1a. 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.
1b. 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).
3. Progress Report
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.
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.