With the hot, dry weather this summer you wouldn't expect to have problems with ear mold in corn this fall. But high humidity and dew during the night, accompanied by hot, dry conditions during the day can be ideal for ear molds in corn.
The molds that form on corn have the potential for mycotoxin contamination. Not all molds on corn form mycotoxins. Aspergillus spp. and Fusarium spp. may produce toxins of concern, while other fungi such as Penicillium and Diplodia are generally more benign, especially if grain is generally intact and undamaged physically.
In areas that will produce some corn, scout for ear molds, recommends Bob Fanning, South Dakota State University Extension plant pathology field specialist. You can begin looking as early at the R6 stage of grow. Check 100 ears of corn from several different places within the field. If more than 10% of the plants have ear mold, it may be beneficial to harvest the field early.
If you think your crop has been damaged by aflatoxin, notify your insurer. Aflatoxin contamination should be covered as long as representative samples of grain were taken before the grain was moved into commercial or on-farm storage. Crop insurance generally ends at harvest, so it is important that your insurer samples the crop prior to storage.
To test grain or feed, you can send samples to the SDSU Plant Diagnostic Clinic, SPSB 153, Box 2108, Brookings, SD 57007. Contact them at 605-688-5545 for information on submitting samples or see the lab's website www.sdstate.edu/ps/plant-clinic.
Services offered include aflatoxin, fumonisin, zearalenone, deoxynivalenol (DON) screens. Cost if $35 for sample prep and the first compound, $15 for each additional compound on the same sample.
For more information managing moldy corn, visit:
"Aflatoxins: Hazards in Grain/Aflatoxicosis and Livestock":
"Dealing with Mycotoxin-contaminated Feeds at Feeding Time":
"Managing Change in Livestock Production Mycotoxins in Feed"
"Corn Diseases in South Dakota" in EC929,
"Best Management Practices for Corn Production in South Dakota"
Source: SDSU Crop and Pest Newsletter.