About a month ago, I received a call from a grain handling facility wanting to prepare their customers for testing of aflatoxin in corn. UNL Extension has several resources regarding aflatoxin and a recent CropWatch article written by Tamra Jackson-Ziems hit on the following key points.
- Drought and high temperatures as we experienced this growing season can promote the development of Aspergillus ear rot; the fungi that cause this disease can produce aflatoxin. Aflatoxin is a mycotoxin which can be toxic to animal and human consumers and at various concentrations can lead to dockage or rejection at grain handling facilities.
- Notable aflatoxin contamination appears to be in a small percentage of southeast Nebraska fields, based on samples submitted to several laboratories in the area.
- At low concentrations, mycotoxins can be safely consumed and are common. Farmers and crop consultants should scout high risk fields for Aspergillus ear rot as an indicator for aflatoxin, but only lab testing of grain samples can accurately identify the concentrations of aflatoxin.
- Laboratories that can test for aflatoxin must be certified by the federal Grain Inspection Service and Grain Inspection, Packers, and Stockyards Administration, or GIPSA. A list of those facilities can be found at GIPSA’S website.
Tamra reports that high risk factors for aflatoxin contamination in corn are:
- Drought-damaged fields, including rainfed (dryland) fields and non-irrigated pivot corners
- Fields or areas with higher incidence of corn ear-feeding insects, such as the corn ear worm
- Grain damaged before or during harvest or after harvest while in storage
Jackson-Ziems also points out that ear rot diseases and aflatoxin are not evenly distributed across fields or in the grain, so scouting and/or sampling should include a substantial portion, at least several acres. Finally, if you have fields at risk of aflatoxin contamination, it is recommended that grain is kept separate from grain at less of a risk.