I’ve spent the last month or so driving around looking at one of the worst volunteer wheat infestations I’ve ever seen — with the only exception being 2016, of course.
Every time I see one of these thick green fields of uncontrolled volunteer wheat today, I am reminded of the millions of dollars in losses from the dreaded wheat streak mosaic virus from several years ago.
And, yes, it could happen again.
Back in ’16, we had a tremendous wheat crop but also had a lot of field loss because many of the billions of small shriveled kernels went right out the back of the combine. The seed source combined with a lot of wet weather resulted in the worst volunteer wheat problem I’ve ever seen.
The volunteer wheat back then became infected with WSMV and served as the green bridge for the tiny wheat curl mite which carried the virus to the next wheat crop. The results were incredible, field-wide losses. A farmer from Wichita and Greeley counties said he had over 3,000 acres of his new wheat crop appraised at between 0 and 2 bushels per acre because of the infection.
Here, where we farm between Dighton and Scott City, literally field after field after field was abandoned. Kansas State University Extension plant pathologist Erick DeWolf asked if I’d collect plant samples from the area and send them in for diagnosis. An astounding 10 out of 10 were infected with wheat streak mosaic or other viral diseases.
And, yes, it could happen again.
We’ve had a lot of hail and shatter loss. That combined with abnormally wet postharvest weather has again resulted in a lot of volunteer wheat.
Control of the disease is very simple—just kill all volunteer at least two 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. In many cases, entire fields of wheat were lost because those neighbors insisted on their right to graze the volunteer or not control it and, thus, force huge unwanted risk on the rest of the neighborhood.
Will it be different this time?
This situation brings up a lot of interesting questions. From an economic point of view, is the volunteer really a cheap source of feed? From my perspective, the volunteer is a weed that is removing moisture and nutrients that won’t be available for the next crop — or that will have to be replaced at a cost, of course. Yields of the next crop can certainly be reduced because of the lost moisture used by the volunteer, and if this is on rented land, do you think the landlord might have an interest in how his costs and returns are being affected. Further, do you think landlords would approve of their tenant using poor farming practices like this. Do they or the farmers themselves have any moral or ethical responsibility to make sure others are not put at risk. Or do they have any legal responsibility.
Outside of volunteer wheat, many farmers have felt Conservation Reserve Program grasses have contributed to the problem by also acting as hosts. While that is true on a very small scale, there are a lot of other alternative hosts including many summer annual grasses like foxtail, barnyard grass, grassy sandbur and jointed goatgrass.
As I drive around looking at fields, I’ve seen a horrific amount of grassy sandbur in county road ditches. We’ve mowed some of those but it would be much appreciated if county governments would recognize they can also play a role in controlling the viral disease by mowing ditches, for instance.
In addition to trying to educate farmers about how to control the disease, DeWolf stresses that volunteer wheat should be killed and that planting can be delayed. Also use resistant wheat varieties like Oakley Cl, Clara Cl and Joe.
KSU entomologist Sara Zukoff says currently labeled insecticides and miticides do not control the wheat curl mite. Neither will seed treatments containing insecticides.