The corn crop, in select areas of the Midwest, has seen severe heat stress this growing season, opening the door to the occurrence of certain grain molds and mycotoxins. Pioneer Hi-Bred International, Inc., advises growers in these stressed areas to manage for possible contamination at harvest and storage.

"There are a few key management steps growers can take to minimize harvest and post-harvest mold growth and mycotoxin production," says Gary Munkvold, research coordinator for Pioneer pathology and entomology specialists." He outlines the following 9 steps.

1.        Monitor fields for evidence of visible mold. If Aspergillus or Fusarium symptoms are evident on a significant percentage of ears, schedule the field for early harvest and rapid drying. Fusarium verticillioides can continue to grow and produce mycotoxins at grain moisture down to about 19 percent, while Aspergillus flavus can do so down to about 16 percent.

2.        Adjust harvest equipment to minimize damage to seeds or kernels and allow for maximum cleaning. Cracked or broken seeds or kernels are more susceptible to mold invasion.

3.        At storage, dry the grain to 13 percent to 14 percent moisture content, if possible, within 48 hours. Long-term storage can be achieved at a uniform moisture of 18 percent for ear corn; 13 percent for shelled corn.

4.        After drying, cool the grain as much as possible through timely aeration; ideally holding the grain at less than 40 degrees Fahrenheit, with good air circulation throughout the storage bin.

5.        Sanitize grain storage units thoroughly each season. Grain molds can survive for long periods within dust and grain residue in storage facilities.

6.        Every few weeks check the condition of the grain for temperature, wet spots and insects. Molds rarely develop uniformly. Hot spots are common in storage units.

7.        Antifungal treatments can be applied to grain to reduce mold growth in storage. These products, such as proprionic acid, do not kill the mold already present nor do they reduce toxins already present in the grain. Do not use antifungal agents on stored grain unless the grain can be marketed after treatment.

8.        Assay moldy grain for mycotoxins. It may be a good investment to collect a representative sample and send it to a laboratory for chemical analysis.

9.        Segregate, blend or destroy contaminated grain. Blending mycotoxin-contaminated grain is not an approved practice by the FDA for interstate commerce. Blending can reduce toxins to acceptable levels in small lots only intended for on-farm use. If the grain has a known mycotoxin, channel the grain to animals that are more tolerant.


For more information on how to manage for molds and mycotoxins, growers should contact their local Pioneer sales professional, or visit:

Pioneer Hi-Bred International, Inc.