Information for this article was taken from a Kansas State University Press Release. The entire article is located at http://www.ag.ksu.edu.

Producers often wait several weeks after harvest before making their first herbicide application to control volunteer wheat,” said Dallas Peterson, K-State Research and Extension weed management specialist. “This allows as much volunteer as possible to emerge before spraying it or tilling it the first time. Often, a second application or tillage operation will be needed later in the summer to eliminate the green bridge to wheat.”

However, hailed out wheat and volunteer emerging during harvest should be controlled immediately after harvest if possible. “Even if this ends up requiring one more field pass than normal to keep volunteer under control throughout the summer, starting early in this situation will help prevent even bigger problems down the road. It should be noted that grazing volunteer is not an effective control option because there is green wheat material left and the mites survive in that material,” Peterson said.

Why the need for early control of volunteer in hailed-out wheat? Where wheat suffered hail damage after heading, volunteer often emerges even before the existing field is harvested – as much as two to three weeks earlier than it would normally emerge after harvest, he said.

Volunteer wheat is especially likely to become infected with wheat curl mites and lead to problems later in the season if left uncontrolled, said J.P. Michaud, entomologist at K-State’s Agricultural Research Center in Hays. “Wheat curl mites will move off growing wheat as the green tissue dries down and dies. If there is young volunteer wheat growing at the time the current wheat crop is being harvested in the nearby region, the mites can quickly infest

those volunteer plants and survive,” he said.

“If volunteer has emerged and is still alive shortly after harvest in hailed-out wheat, wheat curl mites could easily build up rapidly and spread to other volunteer wheat that emerges later in the season. On the other hand, if this early-emerging volunteer is controlled shortly after harvest, that will help greatly in breaking the green bridge. If more volunteer emerges during the summer, follow-up control will still be needed,” Michaud said.

If volunteer wheat and other hosts are not controlled throughout the summer, and are infested with wheat curl mites, the mites will survive until fall and could infest newly planted wheat at that time, he said. Wheat curl mite infestations of wheat often lead to wheat streak mosaic infections.

In conclusion, Michaud advised producers that volunteer wheat also serves as a potential host and green bridge for other cereal grain pests including the Hessian fly, greenbugs, bird cherry-oat aphids, and Russian wheat aphids.

Montana State University U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.