corn borer(redirected from European corn borer)
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(Ostrinia, or Pyrausta, nubilalis), a moth of the family Pyralidae, a polyphagous plant pest. The body length is 13–15 mm, and the wingspread is 27–32 mm. The females are larger than the males. The fore wings of the females vary in color from pale yellow to light cinnamon brown and have two dark zigzag lines at right angles to each other; the hind wings are lighter in coloration and have a light middle band. The wings of the male are darker than those of the female. The caterpillars, which measure about 25 mm long, are light gray or, sometimes, cinnamon brown with a dark stripe across the back.
The corn borer occurs in Europe, Asia, and the Americas. In the USSR it is found in the steppe and forest-steppe zones of the European USSR, in southern Siberia, in the Far East, and in Middle Asia. The caterpillars are injurious to about 230 plant species, mostly such large-stemmed species as corn, hemp, millet, sorghum, and hops. Less often, the caterpillars infest potato, sunflower, ambary, and Chinese bellflower.
Female corn borers lay eggs on the underside of leaves. Caterpillars penetrate the sheaths, leafstalks, inflorescences, and stems. They continue to feed and develop inside the stems and, in the case of corn, inside the cobs. The feeding conditions of the plants deteriorate, the plants break in two, and the stems and inflorescences dry up. There is a sharp decrease in total plant weight, number of seeds, and, in the case of bast plants, amount of fiber.
Control measures include the implementation of sanitary farming practices and the use of resistant varieties. Also effective is the release of the egg parasite Trichogramma (70,000–100,000 per hectare) twice, once at the beginning of intensive egg laying and again ten days later. Chemical methods are difficult to use because of the caterpillar’s concealed mode of life.
REFERENCESKhomiakova, V. O. Kukuruznyi motylek. Leningrad-Moscow, 1962.
Pospelov, S. M., M. V. Arsent’eva, and T. S. Gruzdev. Zashchitarastenii. Leningrad, 1973.