The Enid News and Eagle, Enid, OK

September 22, 2012

Volunteer wheat must be eradicated

Enid News and Eagle

ENID, Okla. — With recent rains over much of northwest Oklahoma, we will have a flush of volunteer wheat.

This volunteer needs to be killed as soon as possible this fall so it will be completely dead at least two weeks before any wheat is planted.

The main reason for wanting the volunteer wheat dead is volunteer is a host for the wheat curl mite. This mite is the most important vector of several wheat viral diseases. The major viral diseases of note would be wheat streak mosaic virus, high plains virus and triticum mosaic virus. With volunteer wheat still alive in the field, the wheat curl mite moves from the volunteer to the newly emerged wheat crop.

Once wheat curl mites leave the volunteer, they can spread to other areas of the field in the wind. The mites can only survive for about a week unless they find another green living host plant like emerged wheat.

Another insect, Hessian fly, also emerges with the recent rains. Hessian flies emerge from over-summering pupae found in old wheat crowns and residue from last year’s wheat crop. Emerged volunteer wheat has the chance to become infested with Hessian flies. If infested, the lifecycle of the Hessian fly population will continue and could re-infest the emerged wheat crop.

Newly emerged volunteer wheat also will be an ideal landing site for an early wave of greenbugs and bird cherry oat aphids. Greenbugs and bird cherry oat aphids can vector barley yellow dwarf to the new wheat crop.

By controlling any new germinated volunteer wheat now, producers can help prevent these insect pests from becoming established in the new wheat crop. This will not guarantee planted wheat will not become infested with barley yellow dwarf from aphids coming in from other locations, or at other times of the year, but it will help.

At this time, most producers will utilize the full labeled rate of a Glyphosate product with the proper rate of ammonium sulfate additives. Some producers may choose to utilize 2,4-D or dicamba where other plant material will not be damaged. These tank mixes will help control weeds that are difficult to control with glyphosate alone and will help reduce the chances that glyphosate tolerant weed populations to develop. If 2,4-D or dicamba is used, plan on a waiting period of three days per ounce of product used in the tank mix. Both products run some risk of injuring emerging wheat.

Your Oklahoma Cooperative Extension Service ag educator will help you with insect control in winter wheat and weed control options that producers can use. Educators are usually located in the county courthouse, or utilize the phone book to give them a call for help.

Gribble is Oklahoma Cooperative Extension Service northwest area agronomist.