Aflatoxins are dangerous toxic chemicals that contaminate many crops. The fungus Aspergillus flavus causes aflatoxin contamination of both cottonseed and corn. Farmers commonly rotate corn and cotton crops in South Texas, where reduced tillage frequently results in long-term residence of corncobs on soil surfaces. A. flavus can grow and survive on corncobs.

Scientists studied the potential of corncobs as sources of A. flavus in cotton and corn crops in South Texas from 2001 to 2003 in order to gain insights into potential methods for preventing contamination. The results indicate that corncobs are an important source of crop exposure to A. flavus. Corncobs from the previous sea-son contained, on average, over 192 times more A. flavus propagules than soil from the same field, and 2-year old corncobs still retained 45 times more propagules than soil. The quantity of A. flavus in corncobs decreased with corncob age.

The results suggest that aflatoxin management should include prompt harvest and techniques to reduce the period corncobs remain in the field, such as incorporation under the soil.