Aflatoxin in Corn before Harvest: Interaction of Hybrids and Locations1

Abstract

Twelve corn (Zea mays L.) hybrids, including one reciprocal, with differences in trypsin inhibitor levels and insect resistance were grown during 1978 at 12 locations in the United States. The study examined the effect of planting date, inoculation with Aspergillus flavus Link ex Fr., and mechanical damage of developing kernels on aflatoxin accumulation in kernels before harvest. Although a broad occurrence of toxin was found in kernels of untreated ears from locations outside the Corn Belt, addition of A. flavus spores to silks markedly increased toxin accumulation. To a lesser extent, mechanical damage was also associated with elevated aflatoxin concert. trations. At specific locations, toxin levels varied among hybrids, but no consistent interlocation pattern of absolute toxin resistance was detected. Visual insect damage on mature ears was not linked quantitatively to toxin levels. More than 90% of the Georgia, Mississippi, Missouri, North Carolina, South Carolina, and Tennessee samples had detectable aflatoxin, but less than 30% of the samples from Illinois, Iowa, and Ohio were toxin positive. In general, bright greenish‐yellow (BGY) fluores. cence in kernels and high levels of toxin were observed, but a number of samples with low levels of toxin did not exhibit the fluorescence.