QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP STUDIES IN PYRETHROID ESTERS DERIVED FROM SUBSTITUTED 3-METHYL-2-PHENOXYBUTANOIC ACIDS AGAINSTCULEX-QUINQUEFASCIATUS

QSAR studies in relation to three physicochemical substituent paramete rs, lipophilicity, electronic and steric factors have been carried out with pyrethroid esters derived from substituted 3-methyl-2-phenoxybut anoic acids against Culex quinquefasciatus applying multiple regressio n analysis by grouping the esters into three based on their alcohol mo iety. In the case of 3-phenoxybenzyl and alpha-cyano-3-phenoxybenzyl e sters the larvicidal activity is mainly influenced by the lipophilic a nd electronic nature of the substituent at 4-position of the phenyl ri ng of the acid moiety. For adulticidal activity the lipophilicity of t he substituent at 4-position followed by that of the substituents at 2 -and 3-positions along with the steric effect are the important factor s for 3-phenoxybenzyl and alpha-cyano-3-phenoxybenzyl esters. The larv icidal and adulticidal activities of 3,4-methylenedioxybenzyl esters a re influenced by electronic factor followed by steric effect of the su bstituent.