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Mycotoxin a problem on heels of hail

By Staff | Sep 25, 2009

Alison Robrtson, left, ISU plant pathologist, discusses hail-damaged corn with Paul Abens, of Gilmore City, during an informational meeting last week in Callender.

By LINDSEY ORY/Farm News staff writer

CALLENDER – Farming is a challenge.

This year is no exception.

Hail pelted fields from Ida Grove to Grundy Center on Aug. 9, affecting an estimated 100 million bushels of corn, and now farmers must figure out what to do with the damaged crops.

To make things worse, ears in the cornfields began to mold.

Hail-damaged corn molding on the stalk.

Those molds prompted a workshop in Callender Thursday offered by the Iowa State University Extension.

“These molds can produce mycotoxins,” Alison Robertson, of ISU’s plant pathology department, said. “Mycotoxins are a chemical produced by the fungus, and they are toxic to humans and animals.”

The toxicity can cause feed refusal or liver damage, reduce conception rates and reduce gain and feed efficiency in herds.

Robertson focused on three toxins: aflatoxins, produced by aspergillus ear rot; fumonisins, caused by fusarium ear rot; and vomitoxin and zearalenone, caused by gibberella ear rot. Only aflatoxins are regulated by the U.S. Food and Drug Administration.

“I know the names can be frightening,” Robertson said, “and just because you have mold doesn’t mean you have mycotoxins.”

To err on the side of caution, Robertson guided farmers through acceptable levels of each mycotoxin. An ear of corn can harbor more than one mycotoxin. The fungi can spread in optimal conditions.

“Our temperatures have not been above 90 degrees,” Robertson said, “and that has probably been our saving grace.”

To prevent the spread of the molds, Robertson encouraged farmers to harvest and dry the damaged corn as soon as possible. Farmers were also advised to not store the corn any longer than necessary. In fact, February was the deadline given to have the grains sold.

However, the economics of that decision didn’t sit well with farmers.

“If my crops are at 23 to 24 percent moisture, the crop won’t dry down anyway,” Ken Anderson, a Callender farmer, said. “Why don’t we just leave them in the field for insurance agents?”

“The cobs will continue to rot if you leave them in the field,” Charlie Hurburgh, ISU professor of agriculture and biosystems engineering, said. “I understand what you’re saying, and you’ll have to take that up with your adjuster.”

For the damaged 40 acres Anderson has harvested, testing for these mycotoxins is timely and difficult to do for yielding only 7bushels.

Tests can be qualitatively or quantitatively conducted. The sample must be 10 pounds worth of grain that comes from a moving grain stream or from multiple probes of the grain cart.

“It’s a very contentious issue,” Hurburgh said.

The problem is that with large volumes of grain going through cooperatives daily to different markets, operators don’t have time to send each truckload through a 10-minute test.

Co-ops are still deciding how they will work with farmers.

The good news is, based on samples taken by NEW Cooperative in Duncombe, no aflatoxins have been detected.

“There were slight traces of fumonisins. Vomitoxin tested at up to10 parts per million, and there were traces of T-2,” Mark Walter, grain manager of NEW Cooperative, told the audience.

“Based upon these tests, we are electing not to take any hail-damaged corn at our facility in Duncombe,” Walter said. “With the feed mill attached, there is no way to handle the hail-damaged corn at that facility. We could separate it, but everyone combines at a different pace, and it’s unrealistic to split it up.”

Walter said the cooperative did find that if farmers adjust their combines it reduces the potential amount of zearalenone as the mycotoxin blows out the back of the machine. However, this didn’t affect the levels of vomitoxin.

As these spores are expelled by combine fans, farmers need to take into account air quality. Robertson suggested farmers wear masks when harvesting these fields to prevent lung irritation.

For Paul Abens, of Gilmore City, it’s the health of his cattle that concerns him.

“I have 80 head of cattle,” Abens said. “I’m more aware of the risk to livestock. I just keep asking questions until I’m comfortable.”

Abens plans on still chopping – making silage – of his damaged corn, but plans on discussing safe levels of mycotoxins in the feed, if they are present.

“I’ll probably test,” Abens said, “and I’ll definitely be talking with my vet about it.”

Test kits can be purchased for $10, and the whole 5-to-10-pound sample must be ground for tests.

Many farmers just want their loss to be covered by their insurance companies and be done.

“I learned a lot,” Anderson said, “but what it boils down to is what the crop insurers tell us to do.”

Contact Lindsey Ory at (515) 573-2141 or lindsey@messengernews.net.

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