Last year, in some cases, corn that was harvested in Mississippi was what could generally be considered high-moisture corn. Some farmers received a premium by harvesting high-moisture corn and taking it straight to the elevator.
However, managing high-moisture corn is not easy since corn that goes directly into on-farm storage needs to be quickly dried to less than 15% moisture (24 hours or less). Drying corn reduces the likelihood of fungal growth on the corn in storage.
Corn placed into grain storage at moistures above 15% can begin to grow fungus if heat and air flow are not constant. In some instances, electricity that was being used to run driers stopped after grain was placed into storage. In as little as 24-36 hours, the corn on top developed a green fungal growth.
Remember, once drying and heating are continued after that period, the fungus doesn’t disappear. The fungal spores that produced the green fungus are still present and can begin to grow again if a conducive environment reoccurs.
Consider the following when initiating grain storage:
- Monitor moisture, and corn with moisture above 15% should be dried to a moisture below 15% within 24 hours.
- Fungal growth on harvested grain can develop in extremely short periods of time if the environment within grain storage is conducive. Mycotoxins can be produced in the field or in grain storage, especially in grain storage if the harvested grain isn’t handled correctly.
- Several fungi can grow on corn and are green in color, but not all of them produce toxins.
- If the presence of aflatoxin is suspected, there are some places that will conduct an analysis to determine the presence and concentration in the harvested grain: Bunge North America (http://www.bungenorthamerica.com/locations/index.shtml); Mississippi State Chemical Laboratory (http://www.mscl.msstate. edu/); or Midsouth Grain Inspection Service at 901-775-1871.
- Don’t store harvested grain in trucks or combines for any period of time following harvest since fungi can grow quickly.
- Once aflatoxin is present in harvested grain, the toxin won’t go away; however, cooler temperatures and reducing moisture in the grain can reduce the likelihood of increasing aflatoxin production.
Tom Allen, Extension Plant Pathologist, and Erick Larson, State Extension Specialist-Grain Crops, with Mississippi State University, co-authored this article.