Repellent, antifeedent and toxic effects of certain plant extracts on cotton leafworm, Spodoptera littoralis Boisd.

Two plants, i.e. Anthemis melanopodia and Artemesia monosperma were tested against the 4th instars larvae of S podoptera littoralis (Boisd.) under laboratory conditions. Four crude extracts (Hexane, Chloroform, Ethyl acetate and Ethanol) from each of the two plants used were evaluated by two different technique, i.e. residual films and dipping. Results indicated different percentage of mortality in larval depending on the efficiency of organic solvent extraction of the active materials from tested plants and method of application. The residual film assay was higher effective technique than the leaf-dipping. Considering the effect of four crude extracts on egg laid by the females resulting from survived larvae. Data revealed that all the tested extracts caused high reduction in egg laying rate compared with the untreated control. As for the effect of tested extracts on hatchability, data indicated that the four extracts reduced egg hatchability percentages and this effect was clearly reflected in the obtained sterility percentages. The effects were more pronounced in residual film than leaf-dipping technique particularly with the higher concentration used