Abstract
In attempt to investigate the genotoxicity and the mode of action of the organophosphorous pesticide; Chlorpyrifos, the pyrethroid pesticide Cypermethrin and their mixture Chlorcyrin, the conidial spores of Aspergillus terreus were treated by five deferent concentrations (including the field concentration, 1ml/L) of each pesticide individually as follows: Conidia were treated with 0.2, 0.4, 0.6, 0.8 and 1ml/L of each pesticide individually. Survival and mutation frequencies were calculated to find out the optimal dose for induction of mutation (by scoring the auxotrophs if possible). As a result, it was found in each experiment that, with increasing of pesticide concentration and exposure time, a decrease in survival percentage and an increase up to a certain limit in mutation frequency were always observed. The optimal dose for inducing mutation by each of the pesticide used, was found to be 0.8ml/L.