Snow mould likely in winter wheat

When farmers are able to get into their fields and check the winter wheat crop this spring, they may find damage from snow mould.

Alberta Agriculture plant pathologist Michael Harding said he won’t be surprised to get reports of such damage, and although no one has noted it yet, the fungus has affected crops in Montana, and that can be an early warning for the Canadian Prairies.

Much of Alberta had prolonged periods of snow cover this winter, even in southern regions where chinooks usually melt the snow several times each winter. That didn’t happen this year.

“I suspect that any perennial forage crop or fall seeded crop, if it had a lot of snow cover on it, there’s the potential for some damage due to those snow moulds,” said Harding.

“We had a very extended period of time where we had snow — in some areas just about from Christmas time until two weeks ago. That really insulates things and it’s ideal conditions for snow mould to grow.”

Symptoms of snow mould damage include leaf lesions and other plant injury, but plants grow out of it once the snow is gone and the growing season is underway.

“Generally speaking, if you had a good, established winter wheat crop or other susceptible perennial crop, at worst you’ll see some dead spots. Most times it’s not economic,” said Harding.

Mary Burrows of Montana State University reported April 20 that mould had killed winter wheat in some parts of the state. She said it wasn’t unexpected given prolonged snow cover this winter.

The damage is usually patchy, and sick plants affected by pink snow mould show leaf lesions with tan centres and a brown halo.

“The good news is that this disease will not infect the spring crop. It requires extended low temperatures and moisture. It is favoured by cool, wet falls and continuous winter wheat planting,” Burrows said in an extension report.

“There is no risk of the fungus spreading to a spring crop should you need to seed to spring wheat.”

On lawns and golf courses, snow mould manifests itself as yellowish circular patches of various sizes. The spores can affect allergy sufferers, causing congestion and itchy, watery eyes.

The Canadian Lung Association recommends that people wear masks while raking lawns this spring to avoid inhaling the mould.

Harding said the same conditions that brought snow mould in fall-seeded crops and perennial forages could also allow wheat streak mosaic virus and stripe rust to overwinter, so he recommends that producers scout crops as soon as they are able.

Those diseases could spring up quickly with the arrival of warmer weather, and catching outbreaks early will give producers more options to deal with them.


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