Winter grain mite and possible return of the Hessian fly may be of concern this fall for Oklahoma wheat producers.
MATURE HESSIAN FLY larvae are brown in color and often referred to as flaxseed. Tillers with larvae will not recover and will eventually die and slough off.
Prevention is the key to managing the pest. “There are no curative treatments for Hessian fly in wheat. If you currently have a field infested with Hessian fly, the first step is to assess the level of infestation. If a plant with four viable tillers has one tiller infected, the impact on yield might not be great, as we could have additional tillering in late winter. A field with most tillers infected is likely a good candidate to graze out.”
He says preparing for next year should begin now. “It is never too soon to be thinking of how to limit the impact of Hessian fly on next year’s crop. Planting a resistant variety still remains the most effective technique in Oklahoma for dual-purpose wheat farmers. To determine which varieties are resistant, consult a current OSU Wheat Variety Comparison Chart.
“Insecticide seed treatments are effective early in the season,” he adds,” but typically do not last long enough to provide season-long control in Oklahoma.” Other options include cultural practices such as crop rotation and delayed planting until mid-October. Those measures might not work for all operations.
Growers should take the pest seriously. Without adequate precautions, wheat used for grazing may suffer significant damage and can be pulled out of the soil by grazing cattle, leaving thinner stands for harvest.
Pulling some wheat stalks is an important diagnostic practice. “Above-ground appearances can be deceiving, so it is important to pull plants to ensure crown roots are there, even if the plants appear large enough for grazing.
“It is also important to prepare fields to measure first hollow stem prior to turning cattle on wheat pasture. Grazing delays plant development; therefore, first hollow stem has to be checked in a non-grazed area.”
The check plot need not be large and can be created with a panel exclosure or by moving an electric fence in a few feet. “The key is to plan for the non-grazed area now so you can measure first hollow stem in February.”
They key for both pests, Edwards says, is to assess infestation levels. Knowing what’s there provides producers information they need to develop management strategies.