TOXICITY OF CERTAIN INSECTICIDES TO Spodoptera littoralis (BOISD.) IN RELATION TO GENETIC STRUCTURE

Abstract

DNA (RAPD), efficacy of certain insecticides against S. littoralis and their effect on total protein, protein SDS-PAGE and the persistence of cypermethrin and chlorpyrifos in and on cotton leaves were investigated. On the basis of LC50 and LC90 levels, cypermethrin was the most potent compound against S. littoralis after 2- days of treatment, followed by esfenvalerate, chlorpyrifos and then B. thuringiensis. The potential of random amplified polymorphic DNA (RAPD) detected genetic polymorphism among the control and treated S. littoralis larvae by tested compounds at LC50 levels.. Five primers revealed differences among control and (dead & alive) treated samples with visible changes in DNA fragments number and size. Primer C1 was the most powerful in detecting polymorphism frequency as 63.6%. Total protein of S. littoralis alive larvae increased at the 2nd,the 4th