Eric DeWolf
DEAD PLANT: Erik DeWolf, Kansas State University professor of plant pathology, points to a plant killed by a fall infestation of wheat streak mosaic. He says that fall infestations result in complete loss of infected fields. Early-spring infestations cause major to total loss of yield.

Wheat streak mosaic back to threaten 2017 crop

Numerous fields in western Kansas show signs of being infected by devastating viral disease vectored by wheat curl mite.

The 2017 Kansas hard red winter wheat crop is going to take a hit from an old, familiar — and preventable — disease.

Wheat streak mosiac, a viral disease vectored by the wheat curl mite, reared its ugly head in western Kansas in the fall of 2016. In fact, because of favorable weather conditions including a late, warm fall, there were fields that were already a total loss by the end of November.

In the spring of 2017, wheat streak mosaic has roared back after an exceptionally warm, windy winter, spreading across a wide area that could reach well into central and south-central Kansas, even possibly into southeastern Kansas. Thousands of acres could be affected before harvest, and acres affected last fall are likely to be wiped out and abandoned.

The major cause of wheat streak mosaic infestation is volunteer wheat — the sprouts of spilled grain — that come up following wheat harvest and provide a home for the curl mites to live and proliferate over the fall and winter.

INFECTION SIGNS: Streaks of bright yellow on wheat leaves, along with a typical curl of the edge of wheat leaves, are signs of infection by wheat streak mosaic. The signs resemble other diseases, and growers who suspect the virus should send samples to the lab at K-State.

The cure for wheat streak mosaic is the control of volunteer wheat — the chemical or tillage destruction of the plants that come up after harvest — depriving the curl mites of a host plant on which they can survive to infest a new crop when it comes up in the fall.

"Unfortunately, there are some people who think of volunteer wheat as ‘free’ pasture. Well, it's not free for their neighbors who bear the losses that the curl mites and the resulting virus bring to their harvest," says Erik DeWolf, Kansas State University research and Extension plant entomologist.

TAGS: Wheat
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