THE COMBINED EFFECT OF PESTICIDE MIXTURES AGAINST COTTON LEAF WORM, Spodoptera littoralis (BOISD.)

Abstract

The cotton leaf worm, Spodoptera littoralis (Boisd.) has developed resistance to various pesticides due to their intensive and repeated use. Insecticides mixtures consider an alternative tool used for delaying or preventing resistance in a certain population. There are many studies about pesticide mixtures against S. littoralis, however, only few studies have evaluated the acceptability of indoxacarb and pyridalyl for mixing. Besides, there are only few studies have evaluated the possible biochemical mechanisms that led to the mixture effect. So, this study aimed to investigate the acceptability of indoxacarb and pyridalyl for mixing, the possible biochemical mechanisms that responsible for mixture effect and the delayed effects of these mixtures against the 2nd instar larvae of the cotton leaf worm S. littoralis (Boisd.). The objectives of the present study are: 1. Evaluating the susceptibility of the laboratory Spodoptera littoralis (Boisd.) strain to the insecticides applied alone under investigation. 2. Assessing the toxicity of the binary mixtures under investigation, as well as, the effect of the biotic potential and biological development of S. littoralis (Boisd.). 3. Estimating the biochemical impacts of Indoxacarb and/or Pyridalyl and traditional insecticides binary mixtures under investigation. 4. Studying the role of oxidative stress of the tested mixtures in raising or reducing the effectiveness of these mixtures and its role in the late effects of the tested mixtures (Delayed toxicity).