Influence of seasonal adaptation on pheromone-mediated behavior of Euschistus conspersus Uhler: Implications for IPM field monitoring in processing tomatoes
Eileen M. Cullen, firstname.lastname@example.org, Frank G. Zalom, email@example.com, Jocelyn G. Millar, firstname.lastname@example.org, and Christine Y. S. Peng2. (1) University of Wisconsin, Department of Entomology, 237 Russell Labs, Madison, WI, (2) University of California, Department of Entomology, Davis, CA
A field behavior study of Euschistus conspersus was conducted over five growing seasons in California processing tomatoes. Twelve fields were monitored weekly, from flower initiation through fruit ripening, using Euschistus spp. pheromone baited traps and canopy shake samples. Additional E. conspersus were collected year-round from seasonal habitats to develop a reproductive profile, and test the ‘oogenesis-flight syndrome’ hypothesis of physiological trade-off between flight capability and reproduction to explain depressed trap response during the mid-summer reproductive period. Adults were dissected to assess thoracic flight muscle condition, and females further dissected to assess reproductive status. Dissection results supported an early season trap catch peak as a biofix from which to accumulate degree-days and forecast nymphal development within the field and indicated that E. conspersus retains flight capability throughout the calendar year. Early season trap peaks were tested as degree-day (DD) biofix dates. Two on-farm demonstrations compared a neonicotinoid plus pyrethroid tank mix, a pyrethroid alone, and an organophosphate standard at early (226 DD) and optimal (327 DD) spray timings relative to the biofix dates and the 310 DD reference for nymphal development as predicted by the E. conspersus phenology model. Mean fruit damage between the two organophosphate timings and the neonicotinoid plus pyrethroid, or pyrethroid alone, treatments timed optimally from the biofix were not significantly different. This study demonstrates the value of using a life history approach to explain insect pest behavior in annual cropping systems and illustrates the emerging role for biologically based, reduced-risk management strategies under production agriculture conditions.