Can volunteer wheat be a danger to wheat crops?
Submitted to Sumner Newscow, Sumner County Extension office — There has been plenty of conversation lately about the amount of volunteer wheat and lack of control this year. There are reasons to worry. The most important reasons to control volunteer wheat are: 
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- Wheat curl mite/wheat streak mosaic virus;
- Take-all;
- Bird cherry oat aphid/greenbug/barley yellow dwarf virus;
- Hessian fly;
- Russian wheat aphid;
- Banks grass mite;
- Reduces moisture loss.
The most important threat from volunteer wheat is the wheat streak mosaic virus complex.
This virus causes stunting and yellow streaking on the leaves. In most cases, the infection can be traced to a nearby field of volunteer wheat – although there are other hosts, such as corn, millet, and many annual kinds of grass. Control of volunteer is the main defense against the wheat streak mosaic virus complex.
Wheat streak mosaic virus is carried from volunteer wheat to nearly planted wheat by the wheat curl mite. The curl mite uses the wind to carry it to new hosts and can travel up to half a mile from volunteer wheat. The wheat curl mite is the vector for wheat streak mosaic, the High Plains virus, and triticum mosaic virus. In addition, the mite can cause curling of leaf margins and head trapping.
Volunteer wheat is a host of barley yellow dwarf virus, greenbugs and bird cherry-oat aphids which carry it. If volunteer wheat is present when greenbug or aphid infestations occur, the insects will find a home on the volunteer and possibly infest planted wheat later.
Hessian flies survive over the summer on wheat stubble. When the adults emerge they can infest any volunteer wheat that may be present, which will keep the Hessian fly population alive and going through the upcoming crop season. This insect often causes significant damage, especially in the eastern two-thirds of the state. Hessian fly larvae attack young wheat plants near the soil line. Tillers may be stunted and later may lodge.
In heavy infestations, the whole state may be lost. The Hessian fly normally has a spring brood and a fall brood. In years with a wet summer and/or a long, open, call, there can be two broods of Hessian fly in the fall; this is even more likely where the volunteer is allowed to grow and become infested early.
