Bt corn and impact on mycotoxins.

Abstract

Abstract This review summarizes the literature linking Bt [ Bacillus thuringiensis ] corn and the reduction of the mycotoxins fumonisin, aflatoxin, deoxynivalenol (DON) and zearalenone. Mycotoxins in field corn cause hundreds of millions of dollars in economic losses annually in the USA, and substantially greater losses in other regions of the world. Most of the losses are from aflatoxin contamination, while significant but smaller losses are due to Fusarium mycotoxins, fumonisins and DON. The insecticidal proteins in genetically modified hybrid Bt corn ( Zea mays spp.) reduce insect damage from certain Lepidopteran larvae, which in turn can reduce infection of the grain by mycotoxigenic fungi. Where such insect damage is a major factor in mycotoxin contamination, Bt corn can lower mycotoxin levels. Since such damage is not always the most important factor, experimental results have been mixed, especially with aflatoxin levels. Bt corn appears to have a greater impact on the Fusarium mycotoxins than on aflatoxin levels. Studies on economic impacts of Bt corn's mycotoxin reduction are briefly summarized. The benefits in developing countries from mycotoxin reduction could be more significant, particularly in regions where unprocessed corn is a staple in the human diet.