ABSTRACTS I

S FOR 92 ANNUAL MEETING PACFIC BRANCH, ENTOMOLOGICAL SOCIETY OF AMERICA March 30 – April 2, 2008 Embassy Suites Napa Valley Napa, California, USA 1. IMPROVED MANAGEMENT OF CUCUMBER BEETLES IN CALIFORNIA MELONS Andrew Pedersen, Larry D. Godfrey, Carolyn Pickel Dept. of Entomology, University of California, Davis, Davis, CA University of California Cooperative Extension, 142 Garden Highway, Suite A, Yuba City, CA In recent years cucumber beetles (Chrysomelidae) have become increasingly problematic as pests of melons grown in the Sacramento and San Joaquin Valleys of California. The primary source of damage comes from feeding on the rind of the developing fruit by adults, and occasionally by larvae, which creates corky lesions and renders the fruit unmarketable, especially for export. Larval feeding on the roots may also be contributing. There are two species of cucumber beetles that are pests of California melons: Western spotted cucumber beetle (Diabrotica undecimpunctata undecimpunctata Mannerheim) and Western striped cucumber beetle (Acalymma trivittatum Mannerheim). Monitoring of both species in Sutter and Colusa Counties began mid-season in July 2007 to investigate biology, distribution, and population dynamics but has not yet produced conclusive results. A study comparing the effects of different insecticide treatments with and without a cucurbitacin-based feeding stimulant called Cidetrak was initiated in the summer of 2007. Cidetrak did appear to reduce beetle numbers when combined with either Spinosad or low doses of Sevin XLR Plus. None of the treatments however, reduced cosmetic damage sustained to the fruit. The limited plot size may have compromised the integrity of the treatments. Future studies will utilize field cages or larger plots in order to prevent movement between treatment plots. 2. PATTERNS OF INSECT CAUSED CUTTING FAILURE WITHIN AN IRRIGATED PERENNIAL CROP R. Andrew Rodstrom, John J. Brown and John R. Rodstrom Washington State University, Department of Entomology, Pullman, WA The inland Pacific Northwest has an ideal climate in which hybrid poplars can be grown as an irrigated perennial crop. Harvest generally occurs during winter, when most root pests are dormant, and by spring the growers replant the recently harvested areas. When these root pests break diapause, their food source has been removed and they actively seek a new food source, potentially causing fatal root damage to the newly planted poplar cuttings. Cutting mortality within a planting unit was recorded following each replant. Using Spatial Analysis and Decision Assistance (SADA) we discerned patterns of insect caused cutting failure within individual units. We found that patterns of cutting failure were consistent for a given pest across all units. These findings suggest that insect caused cutting failures occur in discernable patterns linked to specific pests. These patterns indicate that both sessile and mobile pests attack hybrid poplar cuttings. Our illustration of insect caused cutting failure through SADA allows the growers to identify problematic areas within the farms and address pest problems within individual units based on failure patterns. 3. PREDICTING PARASITOID POPULATION DYNAMICS RESULTING FROM NOVEL INTERACTIONS OF CLIMATE CHANGE AND SELENIUM POLLUTION Casey D. Butler and John T. Trumble Department of Entomology, University of California, Riverside, CA Our research has investigated the individual and joint effects of increased temperatures and the anthropogenic pollutant selenium (Se) on the life history on the parasitoid Cotesia marginiventris (Cresson) attacking the beet armyworm, Spodoptera exigua (Hubner). Previous research has indicated that parasitoids can be affected detrimentally by environmental pollutants, and that changes in insect-plant interactions due to global climate change are likely to have consequences for higher trophic levels. However, information regarding the effects of these factors on parasitoids is relatively sparse. Our specific objective was to determine in a factorial experiment how three temperatures (constant 28.6°C, constant 33°C and a fluctuating temperature between 28.6 and 33°C) and three concentrations of seleno-DL-methionine (0.00, 10.59, and 21.21 μg/g) affected this parasitoid’s survival, development and fecundity. Cotesia marginiventris larvae exhibited a significant temperature by selenium interaction on development time. There were significant declines due to increased temperature, but not selenium, on adult C. marginiventris female lifespan and fecundity. Mean generation times and the intrinsic rate of increase (r) further show that both of these life table statistics declined under conditions of increasing levels of selenium and temperature. These data will be used to increase the potential for the success of biological control programs. 4. IS THERE INTERFERENCE AMONG MEALYBUG SEX PHEROMONES USED IN PHEROMONE-BAITED TRAPS FOR MONITORING MEALYBUGS? R. A. Waterworth, J. G. Millar, J. S. McElfresh, J. A. Bethke Department of Entomology, University of California, Riverside, 92507 Cooperative Extension, University of California, San Diego County, 92078