Cody Creech, Extension dryland cropping systems specialist with the University of Nebraska-Lincoln, watched in frustration as hail decimated numerous wheat fields in his state. Now, he’s worried those fields will set the stage for a tough season next year.
“Hailed-out wheat quickly becomes green volunteer wheat that can host numerous pests, including mites that transmit diseases like wheat streak mosaic virus (WSMV) and high plains virus,” he says. “Of these, the most worrisome is WSMV because of its ability to completely decimate a wheat field.”
In a typical harvested wheat field, wheat curl mite activity diminishes due to lack of suitable host plants. But hail-damaged wheat that greens back up gives mites a “green bridge” that allows them to survive longer.
The mites also make their home on other crops and summer annual weeds, Creech says. Watch out in particular for populations gathering on corn, oats, sorghum, millet, goatgrass, cheatgrass, foxtails, barnyardgrass and stinkgrass.
Volunteer wheat and weeds don’t just host mites, Creech adds.
“They use valuable soil moisture that could otherwise be used to grow next year’s crop,” he says. “In addition, uncontrolled weeds will produce seeds and create future problems.”
Destroy those green bridges through tillage or herbicides, Creech recommends. A two-shot herbicide approach may work best, he says. The first will control initial flushes of volunteer wheat and weeds. Make a second application two weeks prior to planting winter wheat.
Farmers who may be worried they have WSMV can get an overview of the virus along with more management tips in this video presentation by Dr. Bob Hunger, Extension wheat pathologist at Oklahoma State University.