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ARS Home » Research » Publications at this Location » Publication #114722
Title: CONSERVATION OF WHITEFLY NATURAL ENEMIES IN CONVENTIONAL AND IGR-BASED MANAGEMENT SYSTEMS

Author
item Naranjo, Steven
item Hagler, James
item ELLSWORTH, PETER - U AZ, MARICOPA, AZ

Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Studies were continued in 1998 to examine the comparative effect of 2 new insect growth regulators (IGR) and conventional insecticides on the abundance and activity of native natural enemies of Bemisia tabaci. Overall results were very similar to those observed in 1997. Mean rates of parasitism by Eretmocerus eremicus and Encarsia meritoria rarely exceeded 50% in any treatment plot on any sample date and differences among treated and untreated control plots were generally insignificant. Parasitism was consistently higher in plots that received no insecticides for control of Lygus hesperus (compared with plots that were treated. Results for predators were more definitive. Population densities of most predators examined were significantly lower in plots treated with conventional insecticides compared with the untreated control. The IGRs caused reductions in several predator species compared with untreated controls. Based on seasonal means, densities of Orius tristicolor were depressed about 29% in pyriproxyfen-treated plots and densities of Drapetis spp. were depressed about 46-54% in buprofezin and pyriproxyfen plots. Neither IGR significantly depressed populations of any other predator species. Insecticide applications for Lygus bugs consistently depressed populations of all predator species. Combined results from 2 years of studies suggest that use of IGR conserve populations of important natural enemies that help regulate B. tabaci and other key cotton pests.