The Enid News and Eagle, Enid, OK

September 21, 2013

History says control volunteer wheat

By Roger Don Gribble, Extended Forecast
Enid News and Eagle

ENID, Okla. — As I am writing this article, it is raining outside.

With this recent wet weather in much of northwest Oklahoma, volunteer wheat will begin to emerge and grow rapidly. Wet soil conditions may keep producers out of the fields for extended periods of time, making it even more difficult to control volunteer wheat. To protect this year’s wheat crop, the volunteer wheat has to be controlled.

As I learned last year viewing wheat fields in May, the wheat curl mite, which continues its life cycle in volunteer wheat and which vectors wheat streak mosaic virus, can travel at least one-half mile to infect a new stand of wheat. In my 20 years as an area agronomist, I had never seen as much wheat streak as what I witnessed last spring.

This comment was echoed by former Oklahoma Cooperative Extension Service area agronomist Dale Fain, who spent 30 years in that position. That is 50 years of wheat production history saying we have to control volunteer wheat.

The most important threat from volunteer wheat is the wheat streak mosaic virus complex. These viral diseases cause stunting and yellow streaking leaves. In most cases, infections can be traced to a nearby field of volunteer wheat, although there are some likely other hosts of the mites that transmit the virus. Other hosts can be corn, millet and many other annual grasses, such as yellow foxtail or even prairie cupgrass.

Volunteer wheat and the other grass hosts harbor the wheat curl mite during the summer months. These tiny, white, cigar-shaped mites are too small to be seen with the naked eye. The mite uses wind currents to move from host to host and can do so for up to one-half mile.

Along with volunteer wheat hosting the wheat curl mite, it also will harbor Hessian flies, which may cause the wheat plant to lodge at harvest; aphids, which could be vectoring barley yellow dwarf; or even chinch bugs, which feed on developing wheat as it emerges.

Last but not least, volunteer wheat uses soil moisture that is a valuable asset for good growth and development of the 2014 harvested wheat crop.

At this point, a producer has two choices to control volunteer wheat. You will need to choose between tillage or herbicide options. Both are good at controlling volunteer wheat.

The send-home message from this article is producers must control volunteer wheat for two weeks to ensure protection from the discussed pests. That does not mean tilling or spraying a herbicide to kill volunteer 14 days before you plant. It means a producer must have the volunteer wheat dead 14 days prior to planting a wheat crop.

If you need some additional thoughts on controlling volunteer wheat, contact your OCES ag educator. They can provide you with additional thoughts and recommendations for volunteer wheat.

Gribble is Oklahoma Cooperative Extension Service northwest area agronomist.