Hessian Fly: pictures, information, classification and more

Hessian Fly, small fly, more destructive to wheat in the United States than any other insect pest, and also destructive to rye and barley crops. The fly first appeared in the United States toward the end of the 18th century. Its common name has its origin in the belief by Americans at that time that the fly was imported in the bedding straw sent to the Hessian mercenary troops from their native land. At present the Hessian fly is also found in Canada, Europe, northern Africa, western Asia, and New Zealand.

Two or occasionally three generations of Hessian flies appear yearly. The adult, which first appears in spring, is about 2.5 mm (about 0.1 in) long and dark brown to black, with long, beaded antennae and sparsely veined wings. The female lays its cylindrical pink eggs on the leaves of wheat plants. The eggs hatch in about three weeks, and the pink larvae, which turn white in three or four days, bore into the stem and suck the sap, weakening the plant until the upper portions break off. The larvae pupate toward midsummer; the hard, brown pupal skin resembles the outer coat of a flaxseed. The new adults emerge in late summer, mate, and lay their eggs. The larvae of this generation usually pupate in late fall and remain as pupae until the following spring; but occasionally, during a mild winter, they produce a third generation.

Control measures against the Hessian fly include rotation of crops, delayed seeding of a future crop until the autumn brood of flies has disappeared, and planting of wheat varieties resistant to the fly.

Scientific classification: The Hessian Fly belongs to the family Cecidomyiidae. It is classified as Mayetiola destructor.