Toxicidad de insecticidas organofosforados en Musca domestica Linnaeus, 1758, (Diptera: Muscidae), cepa ？El Limón？, estado Aragua, Venezuela

the baseline adult susceptibility of musca domestica l. (diptera: muscidae) from ？el limón？ strain was determined to the organophosphorous insecticides fenitrothion and malathion. the strain was maintained in the laboratory for twenty months without contribution of external material and free of contact with insecticides. three-day old adult males and females were used. the values of dl50 and dl95 expressed in mg/ml for both insecticides were determined by using topical application bioassays (0.6 μl), immobilizing the insects previously by exposing them to low temperatures (-15 °c for 70 seconds). results for fenitrothion of dl50 and dl95 in adults males were 0.8880 and 4.3318 mg/ml, respectively and values of dl50 and dl95 in females were 1.2248 and 4.8112 mg/ml, respectively. for the insecticide malathion, the dl50 and dl95 in adults males were of 60.6269 and 160.8213 mg/ml, respectively and values of dl50 and dl95 in females were of 569426 and 1711323 mg/ml, respectively. the responses of the adult flies of m. domestica from ？el limón？ strain were homogeneous for both insecticides.