10 Sep Kansas Wheat guidance on wheat streak mosaic virus in volunteer wheat
Kansas Wheat has prepared a packet of information available via the button below.
Wheat Streak Mosaic Virus and associated diseases have shown noticeable yield losses in Kansas. In this packet you will find timely information from Kansas State University as well as historical information from the 2017 crop year, which suffered devastating losses due to this disease.
Wheat Streak Mosaic Virus is a growing issue in Kansas. Tests show that the disease showed up not only in western Kansas, but also in central Kansas this year. The best way to stop the spread of WSMV is to control volunteer wheat at least two weeks prior to planting a new crop.
In 2017, this disease caused a conservative $76.8 million in direct losses to wheat farmers, a loss of 19.2 million bushels of wheat. The 2017 loss was 5.6% yield loss, up from an average 1.5% loss.
There are basically only three ways to control the spread of wheat streak mosaic virus:
Timely removal of volunteer wheat and other grassy weeds. The best way to prevent the spread of the wheat streak mosaic virus is to remove volunteer wheat and other grassy weeds.
Volunteer wheat must be completely dead and dry for two weeks before planting a new wheat
crop. Volunteer wheat and other grassy weeds can be removed with herbicides or tillage, but it’s absolutely essential to allow time for herbicides to work. Even if last year’s crop had good genetic resistance to WSMV (such as the variety Joe), it is still important to control volunteer so it doesn’t serve as a green bridge.
Avoid early planting; plant after the hessian fly-free date. By avoiding early planting, Kansas wheat farmers are able to avoid times when wheat mite populations are the highest in late summer and to decrease the interval between planting and fall freeze events. “When we say avoid early planting, we’re not talking about planting outside of the window for success of your wheat crop,” said KSU Plant Pathologist Erick De Wolf. “We’re encouraging you to plant on the later side of the recommended planting dates.”
Plant varieties with moderate or high levels of resistance to WSMV. A number of wheat varieties have resistance to the virus, and others have resistance to the wheat curl mite which carries the virus. Check for resistance when choosing potential wheat varieties suited for your area.
At this point in time, there are no chemical options such as insecticides or pesticides that are effective at controlling the wheat curl mite. Please review the enclosed information and contact Kansas Wheat if you have any additional questions.