What is in this article?:
• Wheat growers across the Upper Southeast planted a big crop of wheat last fall and another warm winter presents some challenges to maximize yield and quality of the crop.
• So far, one of the major challenges in some parts of the region has been managing this late emerging generation of Hessian fly.
DOMINIC REISIG, North Carolina State entomologist, explains Hessian fly damage at a field day last fall.
Planted in window
“Most of our growers with bad Hessian fly problems got their wheat in within the correct planting window. Generally, we discourage early planting, with late planting helping us miss some of the Hessian fly,” says Reisig.
This year was odd, since a lot of our early wheat missed the fly, while timely-planted wheat was hit. However, based on trapping data on adult flies from previous years, it may not actually be such an odd occurrence.
In Virginia and North Carolina, Hessian flies in damaging numbers have been reported and growers should scout for these pests, especially in early- and late-planted wheat with thin stands.
If pupae are found in thinning wheat, applying a long residual insecticide in March may help, but Reisig says to know your variety before spraying insecticides for Hessian fly control in March.
“Our research indicates fields that have some Hessian fly from the fall generation and are planted with a susceptible variety will not benefit from a spring foliar spray.” And, he adds, all fields with a susceptible variety likely will have Hessian fly at some level.
For some growers along the east coast of North Carolina and southeast Virginia, Hessian flies have already destroyed a few isolated fields of wheat.
Reisig says he recently checked several fields with 50-60 acre spots in Pamlico and Hyde counties, in North Carolina that may be total losses due to Hessian fly damage.
In areas with continuous wheat after soybeans, Hessian fly has been a significant problem, and combined with warm winter weather, can be a real threat to what is shaping up to be a good wheat crop in the Carolinas and Virginia.
Reisig says the majority of the damage from Hessian fly has been on wheat that was planted on time. A heavier than usual egg lay this past fall in some areas of the upper Southeast is a particular concern, he adds.
“I’m worried that parts of North Carolina that don’t normally have problems with Hessian flies may have problems this year,” he says.
Based on early reports of Hessian fly damage, Reisig says it’s important to scout wheat to determine if symptoms regularly seen in wheat fields, like yellowing, lack of vigorous growth, lack of nitrogen or cold weather damage; are being caused by Hessian fly.
To scout for pupae, carefully dig up tillers below the soil and peel back the outer layers of leaves. Often pupae will fall out into the soil or will be feeding on the base of the plant behind these leaves, Reisig says.
“Once you have determined the presence of Hessian fly, you need to make a decision about what to do with your field. Our resistant varieties are still holding up well, so you should focus on fields that are planted with a fairly susceptible variety.
“Then separate your fields with susceptible varieties into three categories independent of planting date,” the North Carolina State entomologist says.
These would be as follows
• Fields that have some Hessian fly from the fall generation and are planted with a susceptible variety.
The vast majority of wheat fields in the upper Southeast fall into this category. These fields will not likely benefit from March insecticide sprays.
• Fields that are moderately infested with Hessian fly from the fall generation and are planted with a susceptible variety.
These fields may benefit from a spring foliar spray, but timing will be critical. Reisig says,