Control Volunteer Wheat Before Planting
In 2017, wheat streak mosaic caused approximately $76.8 million in direct losses to producers. The 5.7% yield loss equates to a 19.2 million-bushel loss. We've had some damaging hail and shatter loss. That combined with abnormally wet post-harvest weather has again resulted in some volunteer wheat around the area.
Wheat streak mosaic is a virus that is vectored by the wheat curl mite. Plants infected with wheat streak mosaic have a bright yellow streaking on the leaves of the plant. Symptoms are often most severe near the leaf tip. The virus that causes wheat streak mosaic survives in volunteer wheat and is moved by the wheat curl mite. The disease is often most severe in areas of a field that are closest to these sources of the disease and mites. Commonly plants infected with wheat streak mosaic are also infected with High Plains mosaic and Triticum mosaic. The symptoms of these diseases are nearly identical. Disease severity is greater when plants are infected by more than one virus.
Control of the disease is very simple - just kill all volunteer at least 2 weeks ahead of planting the next wheat crop. But why didn't all farmers do that back then? Some decided not to spray or till their land in order to save money. Others saw the lush volunteer as a free source of feed for their cattle. It may have been free to them, but it cost their neighbors thousands of dollars in lost income.
It will be very similar this year too. There are also a lot of other alternative hosts including many summer annual grasses like foxtail, barnyard grass, grassy sandbur and jointed goat grass. Looking at some area fields, I've seen a decent amount of grassy sandbur in county road ditches. These can be vectors for the mites and the disease too.
in addition to trying to educate farmers about how to control the disease, K-State Research and Extension plant pathologist, Dr. Erick DeWolf, stresses that volunteer wheat should be killed and that planting can be delayed. Also using resistant wheat varieties like Oakley CL, Clara CL and Joe can help too. As far as chemical control goes, there are currently not any labeled insecticides and miticides to control the wheat curl mite. Seed treatments containing insecticides will not help either.
So be a good neighbor and control your volunteer wheat to ensure everyone in the area has the opportunity for a good wheat crop and only has to compete with Mother Nature. For more information on the wheat curl mite and wheat streak mosaic, contact Andrea Burns, Ford County Extension Ag Agent at 620-227-4542.