Hessian fly

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Hessian fly

Hessian fly, European gall gnat, Phytophaga destructor, so named because it was first observed in America shortly after the Hessian troops landed on Long Island in the American Revolution. It is one of the most destructive pests of wheat, barley, and rye. There are usually two generations a year but may be up to five. The adults, 1-10 in. (0.25 cm) long, live only a few days. They lay their eggs on plants, usually where the stems are covered by leaves; the larvae feed on the sap and weaken the plants so that they cannot bear grain. In its winter pupa stage the insect looks like and is called a flaxseed. Some control is achieved by planting winter wheat late, after the adult females have laid their eggs. The Hessian fly is classified in the phylum Arthropoda, class Insecta, order Diptera, family Cecidomyiidae.


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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Hessian Fly


(grain midge; Mayetiola destructor), a mosquito-like insect of the family Cecidomyiidae; a dangerous pest of cereal grains. Length, 2.5-3.5 mm; color, dark gray or brown. The Hessian fly is found in Europe, Asia, and North America. In the USSR it is found in European Russia, Transcaucasia, Siberia, and Middle Asia.

The Hessian fly produces two principal generations. Insects of the first generation fly out in the spring at the time when shoots of spring wheat and barley appear. They do not feed; but they live five to six days, depositing chainlets of up to 500 eggs each on leaves. The larvae penetrate the leaf sheath and attach themselves by suction to the stems. There they pupate in pseudococoons.

In nonchernozem zones and the northern forest-steppe regions the second generation develops in autumn on windfalls and shoots of winter grains. In steppe regions some of the second generation insects fly out in the summer, depositing their eggs on wheat and barley. Because of larval diapause, the remaining second-generation insects fly out in the autumn when the winter crops are sprouting. In southern regions, when there is a very warm autumn, a third generation may develop. The Hessian fly damages mainly winter and spring (especially soft) wheat, and to a lesser degree barley and rye. The most frequent outbreaks of mass proliferation of Hessian flies occur in the steppe regions of European Russia. Sprouts that have not developed lateral shoots are usually destroyed. Those that have developed lateral shoots lose damaged stems. Plants in the reed stage bend and lie down, spiked stems frequently break, and yield is sharply reduced.

Measures of control include early deep plowing, sowing spring grains optimally early and sowing winter grains at their optimal times. Other measures are selection of resistant varieties; agricultural techniques that ensure optimal plant growth and development; and timely gathering of the harvest.


Shchegolev, V. N. Entomologiia. Moscow, 1964.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.