Aspergillis ear rot and Aflatoxin in Corn as well as other ear rots that cause mycotoxins

Aspergillus ear rot, as well as other ear rots were an issue in some areas of Illinois in 2011. Some areas experienced hot and dry weather or STRESS after silking, which are favorable conditions for Aspergillus ear rot as well as Fusarium ear rot.  Other areas, which were lucky enough to get some rain after flowering, may have had a risk of Diplodia ear rot, especially if it was a problem in previous years. In most cases, injury by birds or insects (as seen in the pictures below), allow entry of ear rot fungal pathogens.  Often times, fields that are corn on corn and have reduced tillage allow for the build up of and survival of the ear rot fungi, where it awaits for the right conditions to flourish on a injured or stressed corn crop.

Picture taken by Angela Peltier, U of I Extension Commercial Crop Educator.  Kernals infected with Aspergillus (greenish fungus) as well as Diplodia (white fungus) and possibly Fusarium (starburst pattern on kernal) are present.

Picture taken by Angela Peltier, U of I Extension Commercial Crop Educator.  Kernals infected with Aspergillus (greenish fungus) as well as Diplodia (white fungus) and possibly Fusarium (starburst pattern on kernal) are present.

Picture taken by Angela Peltier, U of I Extension Commercial Crop Educator.  Kernals infected with Aspergillus are present.

In response to this outbreak, Angela Peltier authored the following article:  Corn ear molds make an appearance in western Illinois


 Aspergillus flavus and Aspergillus parasiticus, the fungal pathogens that causes Aspergillus ear rot, produces a very, dangerous mycotoxin that is considered to be a  major carcinogen!  The FDA regulates the allowable amount of this toxin in grain for food or feed and less than 20 ppb (parts per billion) is the allowable amount of the toxin in grain intended for human consumption and immature animals. At the U of I Plant Clinic, one of the diagnostic tests that we use to detect the fungal growth of Aspergillus flavus, is put a black light over the corn ear in a dark room.  The black light will cause corn kernals infected with Aspergillus flavus to glow in the dark.

 

 Some other diagnostic techniques used to diagnose ear rots involve "plating" infected corn kernels on agar to allow the fungal ear rot pathogens to grow.  Identification can be made by spore and fungus morphology.

Aspergillus sp. are not the only fungal ear rot pathogens to produce mycotoxins in corn. For more information on Aspergillus ear rot, see the following link: http://cropdisease.cropsci.illinois.edu/corn/Aspergillusearrot.html

Other ear rots that can cause mycotoxins:

• Fusarium ear rot, often characterized by a starburst pattern on corn kernals, caused by Fusarium moniliforme, F. proliferatum, and F. subglutinans can also produce a mycotoxin called Fumonisin. For more information, see the following link: http://cropdisease.cropsci.illinois.edu/corn/Fusariumkernelandearrot.html
• Gibberella ear rot, often characterized by a reddish mold first on the ear tip, then spreads downward, caused by Gibberella zeae (=Fusarium graminearum) also produces multiple mycotoxins.  For more information, see the following link: http://cropdisease.cropsci.illinois.edu/corn/GibberellaRedearrot.html

In Illinois, to get an accurate test for the concentration of mycotoxins in grain, you can send samples to the Illinois Department of Agriculture CENTRALIA ANIMAL DISEASE LABORATORY

Please call them for further instructions and information.

For more information, contact:
Illinois Department of Agriculture
Centralia Animal Disease Laboratory
9732 Shattuc Road
Centralia, IL 62801-5858
618.532.6701
TDD: 217.524.6858
FAX: 618.532.1195

Need some information on ear rots and grain storage?
Check out this link to another 2011 article written by Dr. Suzanne Bissonnette:   Look at Your Ears-Crop, Stock and Ledger