Aflatoxin Accumulation in Inoculated Ears of Field-grown Maize

Abstract

The rate of aflatoxin accumulation in maize ears that were silk- or wound-inoculated or naturally infected with Aspergillus flavus was examined at Rocky Mount, NC, in 1982 and at Clayton, NC, in 1982 and 1983. In both years, aflatoxin appeared in wound-inoculated ears within 1 wk and increased linearly before peaking 7-9 wk postinoculation (16-21% moisture). Aflatoxin accumulation in silk-inoculated ears followed a similar pattern except that levels of toxin were lower. In both years, toxin levels declined as kernel moisture decreased to 14-16% (P = 0.5). In 1983, aflatoxin concentration was positively correlated with kernel infection and both aflatoxin concentration and kernel infection were negatively correlated with kernel moisture. Two important consideration are evident from the results. First, harvesting maize as early as possible will limit aflatoxin contamination. Second, any comparison of lines of maize for resistance to aflatoxin accumulation should be done during the linear phase of aflatoxin accumulation.