Wheat disease: Is it aster yellows or fusarium?

By 
Reading Time: < 1 minute

Published: August 13, 2012

,

Aster yellows are suspected in the wheat at the top. The wheat below is infected with fusarium head blight. (Les Henry photo)

It’s late in the growing season, but there is still time to scout wheat crops for disease. I first noticed serious disease in my midge-tolerant Goodeve wheat near Dundurn, Sask., not long after flowering.

It took me a while to figure out what was going on; I now know that these diseases are widespread in the Saskatoon area.

While I am a dirt-digging soil scientist and farmer, not a plant pathologist, I think the disease shown in the photo of a neighbour’s Carberry wheat is aster yellows (it hasn’t yet been confirmed by lab tests).

Read Also

The Diverse Field Crops Cluster is a research project examining how to improve crop production while limiting nitrogen emissions. Crops such as camelina, carinata, flax (seen here), sunflower and mustard are the focus area of the project.  Photo: Greg Berg

Manitoba Crop Report: More scattered rains across the province

More scattered showers across Manitoba helped crops advance in their development during the week ended July 13, 2025.

Yes, aster yellows can be a wheat disease, and doesn’t just impact canola. Aster yellows is not a fungus — there is no spray solution. To scout for aster yellows in wheat, look for a white head, with little or no seed. The flag leaf will be curled, with little left, or it may be gone. The stem will still be green in the early stages.

It’s easy to confuse aster yellows with fusarium head blight. All farmers know about FHB and what it can mean, especially in Manitoba. The thought of augering a wheat crop into the bush turns the stomach of any wheat grower. If you have head blight, the heads (or parts of the heads) will be white, but the flag leaf will still be intact, and the plant will still be green.

— Les Henry, a contributing columnist for Grainews and a retired soil science professor, farms and writes in the Saskatoon area.

explore

Stories from our other publications