Submitted to: National Research and Action Plan for Silver Leaf Whitefly
Publication Type: Abstract Only
Publication Acceptance Date: February 4, 1996
Publication Date: N/A
Technical Abstract: The abundance of native parasitoids of Bemisia argentifolii was studied in four vegetable crops with and without imidacloprid. Three fields were set up, each with cantaloupe, collard and tomato. An additional field was set up with sweetpotato. Each crop received either no treatment or a foliar treatment of imidacloprid (Provado @ 0.5 lb/acre for the season). The only yother pesticides used were pre-plant herbicides. Overall, 61% of the captured parasitoids were from the non-treated plots and 39% were from the imidacloprid-treated plots. The primary parasitoid was Encarsia nigricephala (55%) followed by Encarsia pergandiella and Eretmocerus sp., each at ca. 20%. Relative species distribution was not affected by imidacloprid. Whitefly and parasitoid populations peaked in all crops during the third week of sampling (first week of October). On a per trap basis, parasitoid capture was highest in cantaloupe (ca. 15 per trap) and lowest in tomato (ca. 5 per trap). Following relatively high populations of whiteflies during the summer, whitefly abundance was depressed during the fall. Frequent rains during the first half of the study and low temperatures during the second half of the study may have adversely affected the populations of the whitefly and parasitoids.