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EUROPEAN CORN BORER 
 
 (Pyra u s ta n u h ilalis ( H b n . ) ) 
 
 Life History 
 
 Although the European corn borer attacks many cultivated crops 
 and weeds, it is discussed here mainly as an enemy of corn, its 
 favorite host plant. The eggs are laid overlapping one another like 
 fish scales, in small, flat masses of 15 to 20 or more on the undersides 
 of the corn leaves, and hatch in 4 to 9 days. The tiny borers, or 
 larvae, immediately crawl to protected places on the plants, where 
 they feed on the tissues of the immature leaves and tassels, and 
 eventually bore into and up and down inside the stalks and into the 
 ears. They become full-grown in about a month and, after provid- 
 ing an exit for the adult moth, change to pupae inside the burrows, 
 either at once or after an inactive period of varying length. In 10 
 to 14 days the adult moths emerge from the pupal cells and lay an 
 average of about 400 eggs on corn or other plants that they may find 
 in an attractive stage of growth. The moths live from 10 to 24 days. 
 They are active fliers during the evening or night and may migrate 
 several miles. These insects pass the winter in the borer stage inside 
 infested stems of corn or other plants, and here they change to moths 
 late in the spring or early in the summer. There are one to several 
 generations a year, depending on the length of the growing season in 
 different latitudes. 
 
 Control 
 
 A. Destroy overwintering borers by disposal of infested cornstalks. 
 
 1. By feeding to livestock direct or as silage or in finely cut or 
 shredded form. 
 
 2. By plowing under cleanly in the fall or in early spring before 
 the moths emerge, using attachments such as trash shields, 
 wires, or chains to insure burial of all stalks. 
 
 3. By burning infested plants completely where other methods of 
 disposal cannot be used. 
 
 B. Plant as late as practicable, but only within the normal planting 
 period adapted to the locality. Moths of the first brood tend to 
 lay their eggs on the earliest-planted corn. 
 
 C. Plant resistant o^ tolerant kinds of hybrid corn. 
 
 1. No immune strains are available, but hybrids differ in their 
 resistance and tolerance. 
 
 2. Select types that will mature when planted moderately late. 
 
 3. Consult your county agent or your State experiment station 
 on the best hybrids to plant in your locality. 
 
 D. Modify cropping practices. 
 
 1. Avoid sowing fall wheat or other small grain in standing com 
 or corn stubble. The corn stalks should be plowed under 
 cleanly or cut at ground level and removed before seeding 
 small grain. 
 
 2. Dispose of all early sweet corn stalks in fields and gardens 
 immediately after harvesting the ears, by feeding, ensiling, or 
 plowing them under. Cobs and other remnants from the 
 cannery should be disposed of in the same manner. 
 
 E. Use insecticides where practical. o 
 
 1 . Use of insecticides is at present practical only on early market n' 
 or garden sweet corn. c 
 
 2. Consult your county agent or State experiment station for > 
 current recommendations. ^ 
 
 F. Apply as many of the operations suggested above as may be prac- m 
 ticabie under local conditions. Community application of these z 
 methods is necessary for most effective control. 
 
 June 1945 038206 U. S. Government Printing Office 
 
 For saJe by the Superintendent of Documents, Washington 25. D. C. - - Price. 5 cents 
 
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