EVALUATION OF DIMILIN LARVICIDE AGAINST LARVAE OF A. STEPHENSI LISTON, AE. AEGYPTI AND C.ULEX PIPIENS COMPLEX

Abstract

While the «classical insecticides» (DDT: Dieldrin, Malathion, etc.) mainly affect the adult stage of insects, Dimilin belongs to a new group of insecticidal compounds that kills the insect in its larval stages, but has no lethal affect on the adult insect. Its empirical formula is C14H9H2~F2CL. Diflubenzuron is proposed as common name for the trade name Dimilin. Studies were made on C. pipiens, Ae. aegypti, and A. stephensi Liston. Results have shown that this compound affects all larval stages, the eggs and the pupae of these mosquitoes. Dimilin is a stomach poison. Insect larvae which have ingested Dimilin lose the ability to mount and death follows. Histological and biochemica1 studies indicate that the compound does not seem to affect hormonal evaluation of the larvae. It probably blocks the chitin synthesis. Defect show in the newly developed cuticle, so that the larvae cannot withstand the internal pressure or the strain of muscle contraction. In this way molting is impeded and prevented depending on the instars and the species involved.