Effect Of Certain Synthetic Pyrethroids and Bacillus Thuringiensis on cotton Leafworm and American Bollworm

The of the first part of the present work is to evaluate the efficiency of some synthetic pyrethroid insecticides Bacillus Thuringiensis var kurstaki and their mixtures on the egyptian cotton leafworm S.littoralis under the laboratory conditions ,the second part of this work was conducted to study the toxic action of some synthetic pyrethroid insecticides against the different larval instars of H.Zeain the laboratory also the role of mixed function oxidases (MFo) esterases in the action of some synthetic pyrethroids.