The Hessian fly adult is a small fragile fly, sooty black in color (abdomen of female is dull red) and smaller than the common house mosquito. Eggs are reddish in color and are laid in lines of 10 or twelve in groves on the upper side of leaves. The immature are white legless maggots. These maggots work their way down the groves in leaves as far as they can go behind the leaf sheath. Here they rasp on the stem and suck up the sap that oozes from the wound. They do not move once feeding has begun.
Hessian fly feeding damages the stem and reduces plant vigor. The result is weak and stunted plants, which may die in the winter. Spring damage is similar except that plants may produce a "spindly" stalk that breaks easily, rather than die.
For hessian fly problems; a delay in planting until October 10 (north) or October 15 (south) will control this fly. No chemical treatments are recommended.
Map showing normal safe dates for sowing wheat to escape injury by the hessian fly. These are approximate and
will vary some from year to year.
For more information, see Entfact-101