Additionally, since the Hessian fly is a weak flier, putting distance between the location of new wheat plantings and the previous season’s wheat fields can be a successful method of preventing new infestations. Although Hessian fly can become serious under other situations, most serious infestations occur when wheat is early-planted into wheat stubble or into fields next to wheat stubble.

Disking wheat stubble after harvest effectively kills Hessian fly. Planting soybeans no-till into wheat stubble enhances Hessian fly survival by preserving the site where puparia spend the summer. Burning wheat straw will reduce puparia, but many puparia are found below the soil surface. Therefore burning is not as effective as disking.

Choosing cover crops

Serious Hessian fly infestations have occurred in areas where wheat for grain was planted near early-planted wheat for cover or for dove hunting purposes. In cropping systems where cover crops are used, such as in strip-till cotton or peanut production, the use of other small grains besides wheat will reduce Hessian fly populations.

Oats, rye, and triticale are not favorable for Hessian fly reproduction and do not serve as a nursery and are preferred over wheat for cover cropping in areas where wheat for grain is also produced

Delayed planting

Because Hessian fly adults are killed by freezing temperatures, a traditional method for preventing Hessian fly infestation is to delay planting until after the first freeze (often called the fly free date).

This concept has not worked well in North Carolina because an early freeze is not a dependable event. Often a “killing freeze” may not occur until December in many areas of North Carolina, after most growers need to have wheat planted for agronomic purposes.

Variety Selection

Correct varietal selection is probably the most inexpensive and effective method of Hessian fly management. Use the “Wheat Variety Performance & Recommendations” SmartGrains newsletter to keep up to date.

Insecticides

Systemic insecticidal seed treatments provide about 19 days of protection from Hessian fly. If after planting, cold weather sets in within this time frame, these seed treatments can be very effective. Another insecticidal control measure is to apply a long residual pyrethroid to the developing wheat plants at or before the three-leaf stage.

rroberson@farmpress.com