Producers urged to watch for wheat disease

A disease that is wreaking havoc on the U.S. winter wheat crop appears to have shown up in Alberta this year, but damage is not expected to be widespread.

Michael Harding, a plant pathologist with Alberta Agriculture, wants growers to be on the lookout for wheat streak mosaic virus.

“Please keep an eye out for chlorotic (yellow) streaks on leaves of cereal crops,” he said.

“Scouting will be especially important in and around winter wheat fields in southern Alberta, south of Highway 12.”

The disease was found in 12 Alberta fields last year and Harding is pretty certain it is making an appearance again in 2017.

“We’re in the process of getting some samples tested, but we think we’ve already seen symptoms of wheat streak mosaic in Alberta this year,” he said.

It is a devastating disease that is threatening cereal crops in Kansas, Oklahoma, Texas, Nebraska, South Dakota and Montana.

Kansas Wheat recently issued a news release saying the disease is crippling the winter wheat crop in the western half of the state.

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Six counties in west-central Kansas are experiencing “extreme distribution” of the virus.

“Many fields in this area are severely diseased and could experience more than 70 percent yield loss, if not a complete loss,” stated the news release.

The rest of western Kansas is dealing with high distributions of the disease, while the central part of the state has moderate infection.

There is no chemical control for the disease. The only way to manage it is by controlling volunteer wheat because volunteers provide the perfect home for the wheat curl mites that transmit the disease.

Farmers in the winter wheat growing region of the United States have not done a good job controlling volunteers.

“While grazing cattle on volunteer wheat may seem like a cost-effective option in a tough farm economy, not controlling volunteers may cost you and your neighbors down the line,” stated the Kansas State news release.

Harding said the disease is not prevalent in Western Canada be-cause the mites require a “green bridge” to survive the winter. In Alberta, the green bridge can be winter wheat, winter wheat volunteers, grassy weeds or native grasses.

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In the southern U.S., it is far more common to have green tissue year-round because of the mild winters.

Harding said extreme cold snaps this winter combined with open conditions in southern Alberta where winter wheat is grown should help keep the disease at bay.

Randy Kutcher, a plant pathologist at the University of Saskatchewan, said wheat streak mosaic virus has not been a topic of conversation in Saskatchewan this year.

“I don’t have any indication yet that there’s a problem,” he said.

However, Kutcher said the crop is late this year and growers have not had much of a chance to scout their fields, so the disease could still emerge as a problem.

Early signs of the disease include yellow streaking and mosaic patterns on young leaves and stunted tillers. Leaves turn yellow from the tip down, but the veins stay green, producing a striped yellow and green leaf.

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