Toxicity and biochemical impacts of some new insecticide mixtures on cotton leafworm Spodoptera littoralis (Boisd.)

Abstract

The susceptibility to five new insecticide mixtures: chlorosan, feroban, cygron, engeo, and kingbo was studied in the 2^nd and 4^th instar larvae of the cotton leafworm Spodoptera littoralis (Boisd.). The efficiency and residual effects of these compounds against S. littoralis under field conditions were also investigated. Obtained results revealed that feroban was the most effective compared with the other toxicants, while engeo was the least toxic insecticide in both instars after 2 and 5 days from treatment. Data also indicated that feroban had the longest half-life (Lt₅₀) while engeo recorded the shortest one. Biochemical analysis showed that the tested compounds caused pronounced changes in acetyl cholinesterase and phenol oxidase.