September 20, 2013 in Agronomic Crops
Nathan Kleczewski, Extension Specialist – Plant Pathology; firstname.lastname@example.org
Some ear rot causing fungi belonging members of the genera Fusarium, Aspergillus, and Gibberella, can produce mycotoxins. Mycotoxins can be harmful to humans or animals if consumed at certain quantities. Although most infections occur while corn is still in the field, continued growth of the pathogen and associated mycotoxin production can be reduced if the appropriate post- harvest management practices are followed.
1. Before harvest, clean grain bins and dryers inside and out.
2. Within 48 hours of harvest, reduce grain moisture to below 15% for shelled corn and below 18% for ear corn.
3. Store dried grain at cool temperatures (less than 40°F) in clean, dry bins. Grain mold fungi grow well at moderate to high temperatures.
4. Minimize mechanical damage to kernels. This includes harvest and postharvest grain handling and IPM for insect control during the growing season. Wounds facilitate infection of kernels by grain molds while in storage. There is some evidence that the use of Bt hybrids is associated with reduced mycotoxin levels through their effects on insect feeding. On August 29, Dr. Paul Vincelli wrote a nice review of this research in the Kentucky Grain crops Update: http://graincrops.blogspot.com/2013/08/gmos-and-corn-mycotoxins.html?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+GrainCropsUpdate+%28Grain+Crops+Update%29
5. Check the bin every 2-3 weeks for temperature, moisture, and insects.
6. Assay moldy grain for mycotoxin contamination. Contaminated grain should be handled according to the recommendations for the toxin in question. An excellent factsheet on mycotoxin analysis can be found here: http://www.extension.purdue.edu/extmedia/BP/BP-47.html
The following sites provide additional information on mycotoxins in corn: