corn borer

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Related to corn borers: European corn borers

corn borer

or

European corn borer,

common name for the larva of a moth of the family Pyralidae, introduced from S Europe into the Boston area in 1917. The corn borer, Ostrinia nubilalis, has steadily spread southward into the Gulf States and northward and westward across the continent to the Rocky Mts. It also still occurs in most of Europe and parts of Asia. The full-grown larva is about 1 in. (2.5 cm) long, with a dark brown head and pinkish body. It is a major pest of all types of corn, its host preference, but also attacks many other cultivated crops (e.g., sorghum, soybeans, and potatoes) and flower plants (e.g., dahlias, asters, and gladioli). The newly hatched yellowish larvae cause damage by feeding on the leaves of the host plant; older larvae bore into the stalk thereby severely weakening the plant and causing ear damage, which results in a loss in yield and reduction of quality. The full-grown larvae overwinter in cornstalks, corncobs, and debris on the ground. Adults emerge in the spring and are brownish with zigzag streaks across the tips of the forewings. There are sometimes more than one generation per year depending on an increased length of the host's growing season. Control of these pests is complicated by the fact that the larvae also infest common weeds and wild grasses growing near the cornfields. For insecticidal control, see bulletins of the U.S. Dept. of Agriculture. Corn borers are classified in the phylum ArthropodaArthropoda
[Gr.,=jointed feet], largest and most diverse animal phylum. The arthropods include crustaceans, insects, centipedes, millipedes, spiders, scorpions, and the extinct trilobites.
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, class Insecta, order Lepidoptera, family Pyralidae.

Corn Borer

 

(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.

REFERENCES

Khomiakova, V. O. Kukuruznyi motylek. Leningrad-Moscow, 1962.
Pospelov, S. M., M. V. Arsent’eva, and T. S. Gruzdev. Zashchitarastenii. Leningrad, 1973.
References in periodicals archive ?
Adding to the complexity of the model are factors such as the 40 life stages of healthy corn borers, movement from plant to plant, the size of the larvae when attacked by the parasite, and different modes of transmission.
Antixenosis reduces the probability of contact between potential consumers and plants and has been described in some genotypes against the European corn borer (Barry and Darrah, 1988).
Mean values for first- and second-generation European corn borer resistance of maize populations and inbreds averaged from two locations.
And, if you remove infected plant parts and dispose of them away from the garden, the caterpillars will not mature into the corn borer moth and go on to make more corn borers.
Cross-resistance and mechanism of resistance to Cry1Ab toxin from Bacillus thuringiensis in a field-derived strain of European corn borer, Ostrinia nubilalis.
But they may also be useful in helping explain why corn fares so poorly against the European corn borer.
The researchers attribute the collateral benefits enjoyed by non-Bt farmers to areawide suppression of corn borers stemming from long-term plantings of Bt-protected crops.
Potato, green bean and other host crops also stand to benefit from area wide reductions of corn borers, the researchers noted.
Last year, for example, Monsanto introduced YieldGard VT Triple, combining second-generation corn rootworm control, corn borer protection and the Roundup Ready 2 trait for glyphosate tolerance.
They put that shelled corn (into a bean sorter) and I'd run the treadle, and flip the corn borers out," he says.