PARENT SESSION
Oral Session #67: Ecotoxicology and Applied Ecology.
Presiding: W. Snyder
Wednesday, August 7. 1:00 PM to 4:45 PM. Cochise Meeting Room, TCC.
Temperature and host plant effects on the biodemography of Bemisia tabaci in Arizona.
Canas, Luis*,1, Naranjo, Steven2, Ellsworth, Peter1, 1 University of Arizona, Maricopa, AZ2 USDA-ARS, Western Cotton Research Laboratory, Phoenix, AZ
ABSTRACT- The sweetpotato whitefly, Bemisia tabaci (B-biotype=B. argentifolii) is one of the most important pests in the desert southwest of the Unites States. Significant advances in understanding the biology, behavior and ecology of whiteflies have been achieved; however, detailed studies of B. tabaci populations dynamics and the factors affecting population change, especially during the winter, are lacking. Our objective was to determine the factors that govern and limit the year-round development of unmanaged B. tabaci populations at three climatically distinct sites in Arizona. B. tabaci populations utilize hosts sequentially, surviving the winter in broccoli and various weeds and colonizing cantaloupe, Lantana, cotton and weeds during the spring, leading to summer population outbreaks. Life table analyses demonstrated differences in B. tabaci immature survivorship patterns on the different hosts. Generally, the highest survivorship was observed in cantaloupe at all sites (>40%). Host plants with B. tabaci survivorship above 15% included broccoli, Lantana and some weeds. In general, survivorship was lowest on cotton and alfalfa (<6%). Predation and dislodgment accounted for a significant portion of the mortality at all locations. Dislodgment and desiccation were important in some host plants and were probably influenced by low temperatures during winter months. Predation rates were high in all host plants but more so in cotton across the different locations. Parasitism by Encarsia and Eretmocerus varied from host to host and from location to location.
KEY WORDS: Bemisia tabaci, Bemisia argentifolii, Silverleaf / sweetpotato whitefly, Life table analysis