Harvest is moving incrementally and concerns are still very high about fungal ear rot in the corn crop. Let's address some of the most frequently asked questions and observations and wild rumors. What's out there? Is the crop full of toxins? What should I do? Finding ear rot in the corn in the fall is not usually very hard to do even for novice scouts, however, what has surprised many this year is the amount of rot present in fields. In my calls from producers, elevators, and scouts they are reporting infestation levels from 5-35% with some individually higher.

What are the most frequently identified ear rots that we are seeing and are being reported? Well, this is an easy one to answer, Diplodia ear rot is the most frequently seen in our area. Fusarium ear rot is also fairly common this year and some mycotoxins have been reported.

Briefly, Diplodia ear rot is first noticeable in the field by a bleached appearance of the husk. When you peel back the husk, you see a white, fluffy fungus, kernels will be very lightweight and shriveled and of very poor quality. With Fusarium ear rot the fungus can be scattered on the cob or, often, seen toward the middle of the ear. The color is distinctive. Fusarium ear rot can produce mycotoxins in the grain. This is a very serious issue particularly for swine producers. Fusarium ear rot, normally the most common ear rot found in Illinois and the Midwest, is characterized by pinkish to salmon colored fungal tissue growing on the kernels.

Ok what about those toxins? Well, we know that Fusarium can produce mycotoxins and that those toxins are a serious concern for livestock feeding. What about Diplodia? Diplodia is not known to produce mycotoxins in Illinois. There are indeed some reports looking at Diplodia in South Africa where Diplodia infested feed caused the development of a condition called Diplodiosis in livestock. The studies did not make the effort to determine if other fungi such as Fusarium or others were present and may have contributed to the problems. This does raise a very important issue. Typically, we talk about diseases and pests individually but the truth is that they rarely occur all alone. With regard to ear rots in an infested field, the most prevalent one this year may be Diplodia, but that doesn't mean there is no Fusarium in the field or even other fungi. Common sense tells us that significant caution should exerted when thinking about using a fungal infested field or grain for feed. It should not be considered at all for young or breeding animals or swine.

If you have ear rot in the field, what should be done? Well, the weather is not cooperating in the least to get the infested ears out of the field. Getting the corn harvested and dried to a moisture percentage where the fungus will not grow and spread along the ear is imperative for management. This assumes two things, first that the grain is mature, and second that you can actually get it out of the field. Ear rot fungi will continue to develop on the cob in the field or in storage at above 18% moisture. If dry weather is expected you can try to save some drying costs and leave the grain to dry a bit longer in the field. If you have moderate infection and mature grain though and wet weather is expected, harvesting and drying to at least 18% is probably your best option.