Submitted to: Bemisia International Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/4/2006
Publication Date: N/A
Technical Abstract: A large multi-institutional, interagency classical biological control program was initiated in the early 1990s to combat the invasion of the B biotype of Bemisia tabaci into the US. This large program was successful in the discovery, importation, rearing and release of >30 species/strains of aphelinid parasitoids from around the world into multiple states and the establishment of several species in each targeted state has been documented. Two exotic species (Eretmocerus nr. emiratus and Encarsia sophia) have become established in Arizona and have largely displaced native aphelinids. However, the impact of these establishments and the overall biological control program in Arizona and elsewhere is unknown. From 1996 through the present in situ life tables have been constructed for B. tabaci on cotton in Arizona. Analyses of these life tables demonstrate that parasitism varied across years at low to moderate levels but that there is no trend for increasing levels of parasitism since the exotics became established. Additional analyses showed that the irreplaceable mortality supplied by parasitism has not increased since establishment and that parasitism has no explanatory value in predicting total generational mortality. Predation has consistently been the largest source of mortality, has consistently contributed the largest amount of irreplaceable mortality and represents the key-factor explaining variations in total mortality both before and after the establishment of exotic aphelinids.