A COMPARATIVE STUDY ON SUSCEPTIBILITY OF THE LARVAE OF TWO WILD STRAINS OF ANOPHELES STEPHENSI TO EIGHT INSECTICIDES, IN SOUTH OF IRAN

Susceptibility of two wild strains of An. stepliens, collected from Kazeroun (ST-K.Az and Bandar-Abbas (ST-BAN), south of Iran was compared to fenthion, malathion, temephos , pirimiphos, methyk, deltamethrth, DDT dimilin and etopenprox as larvicides in the laboratory. Susceptibility test on the ST-KAZ strain indicated that this strain is susceptible to the named insecticides i.e. the resistance ratios remained between 0.91 to 1.37 folds that of the ST-TEH strain, the susceptible laboratory stock .The ST-BAN strain has the long history of insecticide — application like, DDT, dieldrin, malathion, propoxur, actellic lambdacyhalotith(icon) as adulicides and abate as a larvicide, therefor it showed different pattern of susceptibility to the latter insecticides. The ST-BAN strain showed susceptibility to DDT, deltamethrjn, etofenprox and dimilin, moderately tolerant to fenthion and temephos (i.e.reslstance ratios ranged between 1.67 to 1.75 folds) and tolerant to Pirimiphos~methyl and malathion with resistance ratio of about 2.37 folds , that of the ST-TEH strain. The observer’s tolerance in the ST-DAN strain to Pmmiphos-methyl (actellic) and malathion might be as the result of regular use of adulticides or abate in malaria control programs in south of Iran and develop of cross-tolerance in An.stephensj from Bandar-Abbas south of Iran