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Title: EFFECT OF COTTON CULTIVAR ON PARSITISM OF SILVERLEAF WHITEFLY BY ERETMOCERUS SP.

Author
item SIMMONS, GREGORY - USDA-APHIS PPQ,BRAWLEY,CA
item NATWICK, ERIC - UCC EXT, HOLTVILLE, CA
item CHU, CHANG CHI
item COHEN, ALLEN
item BRUSHWOOD, DONALD

Submitted to: Silverleaf Whitefly: 1997 Supplement to the Five Year National Research and
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Four replicate blocks of 17 cultivars of cotton were grown in a randomized complete block design with pesticide and no-treatment as a split factor at U.C. Meloland field station to determine if cultivar type had any effect on parasitism of silverleaf whitefly by naturally occurring Eretmocerus sp. Six node 8 leaves were collected from each treated and non-treated plot. Random samples were collected from the inner two rows of each plot, 3 leaves per row. Samples were examined in the laboratory and all whitefly (SLW) pupae, emerged SLW, Eretmocerus pupae and emerged Eretmocerus were counted within a 2.7 cm sq disk placed at the base of leaf sector 1. Percentage of parasitism was calculated by dividing total number of Eretmocerus by total number of Eretmocerus plus emerged SLW. Percentage of parasitism was transformed using the arc-sine transformation. A split-plot analysis of variance was performed using insecticide treatment as the split tfactor. Means were separated using Tukey's HSD mean comparison procedure. There were no significant cultivar by insecticide treatment interactions on either date, though insecticide treatment had a significant effect on parasitism on 23 July. No significant effects of insecticide treatment on parasitism were found on 8 August. Parasitism levels in the insecticide treated plots ranged from 8-58% and 26-70% on 23 July and 8 August respectively.