Winter wheat producers’ harvest yields may decrease this year, and a mycotoxin may be to blame.

Deoxynivalenol, also known as DON or vomitoxin, according to an NDSU Extension Service fact sheet, is produced in wheat and barley grains whose heads were infected with Fusarium head blight, or FHB. Grain heads become infected when wet weather occurs during flowering and filling. Infected grains may have kernels that are chalky white, shrunken and/or scabby in appearance.

The Food & Drug Administration has set levels at which DON can be present in grains to be consumed by humans and animals. For human consumption, grains infected with DON are limited to one part per million, or one kernel per 80 pounds of wheat. However, while humans would have to consume large quanties of DON-infected grain in order to feel any ill effects, DON does affect the taste and processing of grains.

For animals, the FDA has set an acceptable level of five ppm for swine and horses and 10 ppm for poultry and beef and feedlot cattle.

Infected grains can also be milled or screened out before they are used for feed or sent to market.

In livestock, signs of DON toxicity are reduced feed intake. DON causes the brain to increase uptake of trytophan, which increases the synthesis of serotonin. Both cause reduced feed intake.

Tim McKay of the Farmers Union Elevator said for going the market, sellers look for grains with DON levels at two ppm or less.

“If it gets too high, it’s not sellable,” McKay said.

McKay said some of the winter wheat that has reached the elevator contained, on average, seven to eight ppm of DON.

Jayme Berube, of Berube Crop Insurance in Rugby, said DON is present in the Pierce County area, but other areas have been affected in worse ways.

“We got it in the area, it’s out here, it’s not as bad as some areas,” Berube said. “There are fields out there that are being burned, and there are fields out there being harvested that might have to be destroyed after they’re done harvesting.”

Areas affected severely were farms in and near Rolette and Bottineau counties.

Berube said a chemical spray can be used to treat DON, depending on the timing.

“We hope to never have vomitoxin, but you get it on wet years,” Berube said. “The moisture would be fine if we had normal temperatures, but we’ve probably been cooler than normal, which is perfect for small grains. Small grains love it cool and damp. The row crops generally don’t like this weather. They want moisture but they want it hot.

“I’d say we’ve been on the cooler side and wetter side. It’s been that way since April, it’s been steady all the way through and we haven’t seen any relief from it,”Berube said.

Berube also said in the northern areas, where DON levels were severe, an early frost affected soybean harvesting.