Performance of Certain Pyrethroids and IGR / Pesticide Mixtures Against Sucking Pests and Beneficial Arthropods Associated with Cotton in Late Season (Mid-Egypt, 1992)

S.A. Ibrahim, M.A. Younis and M.S. Fouad


Four IGR/pesticide mixtures that are recommended in Egypt to control cotton bollworms were evaluated. The first part of this study, was conducted in 1990 and 1991 for evaluating those mixtures in comparison with four synthetic pyrethroids against cotton bollworms, cotton seed bug (Ibrahim et al 1993), and cotton leafworm (Ibrahim 1994). The second part of this study was conducted in 1992 to study the efficacy of those pesticides against five sucking pests associated with cotton in late season, cotton aphid Aphis gossypii Glover, sweetpotato whitefly (SPWF) Bemisia tabaci Gennadius, onion thrips Thrips tabaci Lindeman, cotton leafhopper Empoasca spp. and the two-spotted spider mite Tetranychus urticae Koch. Special concern was directed to the side effects on beneficial arthropods. Data from three applications started on July 28 showed that mean numbers of cotton aphid in all pesticide treatments except Tamaron-combi (Triflumuron + methamidophos) were significantlly less than the control treatment. Data of percent control shifted Delfos-2 (hexaflumuron + chlorpyrifos-ethyl) and was considered ineffective in controlling cotton aphid in late season. On the other hand, the pyrethroid Mavrik (fluvalinate) and the mixture Deneet (diflubenzuron + methomyl) showed the highest potency with about 80% aphid control. The efficacy of all tested pesticides as percent control was less against the mature stage. Tested pyrethroids were more effective in controlling B. tabaci than tested IGR/pesticide mixtures. Talistar (biphenthrin) showed the highest whitefly control. None of the tested mixtures offered more than 40% control. Moreover, Tamaron-combi was ineffective. All pyrethroids tested and the mixture Katabron (Chlorfluazuron + profenfos) resulted in about 40 to 60% less thrips infestation than the control treatment. The rest of the mixtures were less effective. The highest reduction in Empoasca spp. was recorded in Fenval (Fenvalerate) treatment (57.9%), followed by Deneet (47.2%). The pyrethroids Mavrik, Talistar, and Fenval showed miticidal activity ranging from 28 to 55% control. The rest of treatments were ineffective. Although mean numbers of parasites and predators in all treatments (except Delfos-2) were statistically similar, the percent reduction showed about 50% or more reduction in the mean numbers of parasites in all pyrethroid treatments as well as in Delfos-2 treatment. Bestox (alphamethrin) and Delfos-2 treatments significantly reduced the population of predators by about 40 to 50% less than the untreated check. General cotton infestation with the five pests in late season was lower in Confidor/Bestox treatment and no valuable natural enemies were recorded in this treatment. The low populations of sucking pests and beneficial arthropods were recorded even before applying Bestox.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pp. 932 - 937
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998