Inhibition of aflatoxin B1 production by insecticides registered for use on corn

Aflatoxin production and Aspergillus flavus growth appeared to reduce as insecticides concentration increased from 10 mg/liter (ppm) to 100 ppm concentration. The insecticide naled completely inhibited production of afla-toxin B₁ and growth of A. flavus at 100 ppm. The insecti-cides bux, carbaryl, and dyfonate significantly (P = 0.05) inhibited production of aflatoxin B₁ by 97, 55 , 64% respectively, at 100 ppm. However, at a concentration of 10 ppm, significant inhibition in production of aflatoxin B₁ was found only with naled and dyfonate. Carbofuran did not significantly inhibit aflatoxin production even at 100 ppm. The insecticides bux, carbofuran, dasanit, and EPN showed significant (P = 0.05) inhibition of A. flavus growth by 53, 50, 24, and 20% respectively at 100 ppm concentra-tion. Field samples inoculated with A. flavus but not treated with insecticide showed an increase in aflatoxin B₁ production in all experiments. Treating uninoculated corn with the insecticides bux and naled did not reduce toxin pro-duction, however, treating uninoculated corn with carbaryl did significantly reduce toxin production. Although car-baryl and naled appeared to reduce toxin production in inoculated corn, this reduction was not found to be signif-icant due to experimental variation. Since the insecticide carbaryl reduced aflatoxin B₁ production in uninoculated corn significantly, it may be of value under field con-ditions when spore loads are low.