Utilization of Bacillus thuringiensis to control Spodoptera littoralis in Egyptian clover fields

The efficacy of the commercial. product Dipel, 2X (Bacillus thuringiensis v ar. kurstaki), was assessed as a biological control means of the cotton lea f worm Spodoptera littoralis attacking clover cultivations (Trifolium alexa ndrinum) in Egypt. Field experiments using the biological agent were carrie d out in two localities as compared with the conventional chemical insectic ide lannate. The percentage of reduction in the larval population increased at higher doses of B. t. and the infestation levels reached very low level s, almost similar to those obtained after using lannate. The yield of the first cut of clover was estimated. The data obtained indic ate that the yield significantly increased after treatment with either B. t , or lannate. In Menoufia, the yield was significantly higher after two suc cessive spray applications with B. t. at 750 g/f compared to that obtained with B. t. when used at 500 g/f. In Giza Governorate, the yield was slightl y higher after a single treatment with B. t. at 500 g/f as compared with la nnate.