Ear mold problems do not appear to be widespread

As the tough 2011 cropping year draws to a close, farmers can take solace in knowing that despite unfavorable weather conditions, corn molds don’t seem to be of widespread concern, says a Purdue University plant pathologist.

Summer drought often leads to Aspergillus ear rot infections in corn, which produces aflatoxin — a carcinogen and liver toxin that affects livestock. Luckily, it doesn’t look like most farmers will have to worry too much about it.

“People might have yield problems with late planting and drought stress, but it doesn’t appear that ear rot will be a widespread problem this year,” said Charles Woloshuk.

Aspergillus ear rot is common in plants with drought stress because it thrives in weak plants. Since many other diseases need cool weather to survive, Aspergillus has little competition.

Woloshuk also said many of the other grain diseases don’t seem to be a problem this harvest. One common concern is Gibberella rot, which is associated with another toxin, called vomitoxin or DON. However, Gibberella thrives in cool weather during silking and pollination — something farmers didn’t experience this year.

“Since the corn’s growth stages were behind and we had a dry summer, Gibberella isn’t a problem,” Woloshuk said.

The one corn disease that producers and horse owners may want to keep an eye on is Fusarium ear rot. This particular ear rot has been associated with neural tube defects in humans and illnesses or death in horses. The fungus tends to live in hot weather and is relatively common — especially in south of I-70 and in sandy, drought-prone soils. So far this year, however, Woloshuk said he’s received no reports of widespread disease.

Ohio State University Extension plant pathologist Pierce Paul did receive reports of ear rots in some fields early in the harvest and, understandably, after the vomitoxin problems of 2009, producers are asking whether we are likely to see a similar problem again this year. He agrees, though, that the problem does not appear to be widespread.

If ear molds are discovered, Paul advises growers to follow certain harvest and storage guidelines to minimize problems associated with kernel rots and mycotoxin contamination. Growers should:

1. Harvest at the correct moisture and adjust harvest equipment to minimize damage to kernels. Mold and mycotoxins tend to be higher in (machine or insect) damaged kernels.

2. Dry harvested grain to 15% moisture and below to prevent further mold development in storage.

3. Store dried grain at cool temperatures (36-44F) in clean, dry bins. Moderate to high temperatures are favorable for fungal growth and toxin production.

4. Periodically check grain for mold, insects, and temperature.

5. If mold is found, send a grain sample for a mycotoxin analysis to determine if toxins are present and at what level. For more on moldy grain, mycotoxins, and mycotoxins sampling and analysis visit the following websites:

http://oardc.osu.edu/ohiofieldcropdisease/t01_pageview2/Home.htm

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