WSM, better known as wheat streak mosaic, transmitted by the wheat curl mite, is a scourge of wheat and a thorn in the side of wheat producers on the High Plains region.

As has been long proven by wheat breeding experts and farmers, timely control of volunteer wheat following harvest is the best method for eliminating this yield-robbing disease. However, it persists, not because we do not know how to control it, but because not all producers are actually controlling it.

The threshold level for devastating impact on wheat health is low. Only one field of volunteer, even a small part of the field, can spread the curl mite to surrounding fields, resulting in extensive yield loss.

While attending this year’s wheat quality council briefing in Wichita, we learned the economic impact of WSM was severe, especially in western Kansas regions. It was not absent in central Kansas, either.

This year, two of our fields in Dickinson County suffered losses, cutting yields by a third. Though yields also suffered from the effects of freeze damage, the greatest impact was already in place during early spring green-up and jointing. Another local farmer reports production losses double ours.

Hardly a year passes without a wheat field damaged by WSM, not because of our failure to control volunteer, but because of the curl mite migrating on prevailing winds from neighboring fields.

Producers grazing cattle also see value in grazing volunteer wheat, or they plant a forage crop in wheat stubble without controlling volunteer wheat prior to seeding. This practice has become a primary source of curl mite infestations in our region.

However, controlling the “green bridge” for curl mite habitat is becoming a critical issue for wheat farmers everywhere. It is a sensitive subject to discuss with neighbors who may be longtime friends, requiring a diplomatic, non-combative approach that is reflective of a relationship built up over the years. That said, yield losses and their financial impact cannot not be ignored any longer.

Though an effort has been made to educate producers about the negative economic impact resulting from lack of control of volunteer wheat, other efforts previously mentioned in this publication and elsewhere should continue. If we do not find ways to address this issue in the near future, this will continue to fester, ultimately coming to a head in ways that are unpleasant and more difficult to control.

Penner is a Marion County farmer and past president of the National Association of Wheat Growers. His email is [email protected].