Nontoxic strains of a fungus have been developed by the Agricultural Research Service (ARS) to control aflatoxin in corn.
Aflatoxin is a naturally occurring mycotoxin produced by the fungus Aspergillus parasiticus and the more common A. flavus. The fungus is most often found when certain grains are grown under stressful conditions, such as drought. Aflatoxin occurs in contaminated agricultural commodities, such as corn, peanuts, cottonseed and nuts, and may also be found in soil, decaying vegetation, hay and stored grains during moist and hot conditions.
ARS scientists developed two fungal strains that don't produce these toxins in corn crops. The two nontoxic strains of A. flavus competitively displace, or out-compete, the pest strain, according to Hamed K. Abbas, an ARS plant pathologist in Stoneville, MS.
Using the beneficial fungus to treat soil that naturally contains high levels of toxin-producing Aspergillus reduces contamination of corn by 60-85%. When a nontoxic fungal mixture was mixed with toxin-producing A. flavus and used to treat soil, corn had 65-94% less aflatoxin, compared to corn grown in soil treated with the toxin-producing fungal strain alone.
Further trials are needed to demonstrate that the fungal mixtures are effective under varying conditions naturally found in southern corn production. Additional research will determine the most effective and consistent application methods.