Acute and Latent Efficacy of Certain Pyrethroids and IGR/insecticide Mixtures Against Spodoptera littoralis (Boisd.) (Mid-Egypt, 1991)

Sanaa A. Ibrahim


The mixture of IGR with chlorpyrifos-ethyl (Delfos-2) showed the best ovicidal activity against spodoptera littoralis egg masses. Surviving neonates in pesticide treatments consumed less cotton leaves than those of the control treatments. The reduction in leaf damage was more than 80% in all pesticide treatments. Initial larvicidal activity of all tested pesticides after twenty-four hours against sixth instar larvae was not significant. Five days post-treatment, the pyrethroids Bestox and Talistar, and the mixtures Deneet and Katabron resulted in 100% mortality for laboratory strain larvae. Only Talistar and Delfos-2 resulted in about 80% cumulative mortality with cotton strain larvae. Larvae collected from soybean showed the least toxicity response of all tested pesticides. Tested pyrethroids except Mavrik reduced food consumption even after allowing larvae to feed on untreated leaves. The rest of pesticide treatments reduced food consumption on treated leaves. Treated larvae fed more than control larvae when they were allowed to feed on untreated leaves. The tested pesticides except Deneet did not affect larval and pupal durations. Tested mixtures were more potent in disrupting pupal formation than tested pyrethroids. The weight of pupae was significantly less in Deneet, Tamaron-combi and Talistar treatments. The tested mixtures showed latent pupicidal activity; Katabron and Delfos-2 treatments completely distrupted adult eclosion. Adults that emerged in Deneet and Tamaron-combi treatments laid few inviable eggs. The pyrethroids, Bestox and Mavrik did not affect adult fecundity and fertility.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pp. 1081 - 1084
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998