September 28, 2007

Elevated Aflatoxin Concentrations in Some Southeast Nebraska Corn

Aspergillus ear rot that can lead to aflatoxin accumulation.

Aflatoxin is a mycotoxin produced by fungi in the genus Aspergillus, most commonly A. flavus. This fungus is commonly present in the soil and can cause ear rot diseases under certain conditions. The fungus causing Aspergillus ear rot of corn produces copious amounts of greenish-yellow spores (Figure 1), particularly on damaged kernels. The presence of the fungus in kernels does not correlate with the presence of aflatoxin, nor does the absence of visible fungal growth correlate with the absence of aflatoxin.

Drought and high temperatures tend to favor the production of aflatoxin in corn. Portions of southeast Nebraska missed some late-season rain events received by much of the rest of the state. Irrigation is not as common in fields in eastern counties, thus crops rely solely on rainfall for moisture and are at higher risk for drought stress. This may be to blame for the aflatoxin in this area this year.

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