B. tabaci is one of the most serious pests attacking industrial and food crops through the desert southwest of the USA. Although significant advances have been made in understanding the biology, behavior and ecology of B. tabaci, pest management systems still rely on very few control methods. In an effort to increase the control options available, we engaged in the study of the biodemographic characteristics of B. tabaci during the year, placing special interest on the winter months when populations are scarce and might be more vulnerable. From the six host-plant systems studied, two of them, cantaloupe and Lantana hybrida provided a good environment for the buildup of B. tabaci populations from September to October. Populations of B. tabaci were extremely high in these plant hosts. However, B. tabaci populations declined steadily in accordance with decreases in temperature. Low temperatures affected the host plants, with both cantaloupe and Lantana plants dying from freezing temperatures. Decreases in B. tabaci populations were more apparent in the egg stage. The number of small and large nymphs remained at a similar level until the initial days of November, suggesting a higher tolerance to low temperatures in immature B. tabaci. The study of several B. tabaci cohorts (life table analysis) showed the most important mortality factors were desiccation (46%), egg inviability (23%) and predation (12%). For nymphs, most of the mortality was allocated to the category unknown (89%), which includes the death of nymphs due to cold weather and/or leaf desiccation. Our study has provided a glimpse of the effects of low temperatures on the different whitefly stages. Adult whiteflies appear to be more susceptible to low temperatures than the immature stages. In addition, developing immature whiteflies sometimes are able to complete their development even when low temperatures kill the host plant.
Species 1: Homoptera Aleyrodidae Bemisia tabaci (sweetpotato whitefly)
Keywords: life table, plant insect interactions
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA