Submitted to: XXI International Congress of Entomology, Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2000
Publication Date: N/A
Technical Abstract: Evidence from many of the agricultural systems affected by Bemisia tabaci suggests that natural enemies are an important component of natural control. Maximization of the effects of natural enemies should form the foundation of modern pest management systems. Their integration into IPM has been hampered in many systems by a poor understanding of the overall impact of natural enemies on pest population dynamics and the interaction with other control tactics. The relative effects of aphelinid parasitoids on Bemisia have been characterized in a number of cropping systems by measuring percentage parasitism. Clear geographic as well as host plant- related patterns have been identified. Still, great care must be used in relating such measures to pest population control. Predation is less well understood because of measurement difficulties; however, serological and other techniques have helped to identify key predator species in several cropping systems and it is clear that a large number of generalist predato species attack Bemisia. The impact of pathogens is poorly known in most systems. Conservation of natural enemies in IPM systems depends on a number of factors. The greatest impediment to conservation biological control in IPM systems for most crops are insecticides. Toxicological studies have been conducted on various parasitoid and predator species attacking Bemisia. These studies have revealed potential direct and sublethal impacts, but it is difficult to extrapolate findings to the field. Controlled field studies in some cropping systems have also been used to characterize the gross effects of insecticides; however, such studies can overlook behavioral and more long-term effects.