Effect of dichlorvos [an organophosphate insecticide] on aflatoxin and versicolorin A production in Aspergillus parasiticus

Dichlorvos, an organophosphate insecticide, inhibited the production of aflatoxins in wild type A spergillus parasiticus at 10, 20, 50, and 100 ppm, and of versicolorin A in wild type and mutant A parasiticus. The production of averufin and versicolorin C was only moderately inhibited by dichlorvos. At 20 ppm, dichlorvos blocked the incorporation of label from 1-14C sodium acetate into aflatoxins in resting cell cultures of the wild type. Controls of resting cell cultures of a wild A. parasiticus showed 34 5% conversion of label from14C versicolorin A; 20 ppm dichlorvos lowered this conversion to 13 0%, indicating only partial blockage of this reaction.