Wire-worms (Elateridae). — Hard, yellowish, or reddish, cylindrical larvae feeding on the roots.

Preventives. — Crop rotation ; let clover intervene between sod and corn, planting the corn late the second or third year. Early fall plowing.

Cut-worms (Agrotis, Hadena, etc.). — Soft-bodied caterpillars eating and cutting off the young plants. See p. 302.

Preventives. — Early fall plowing of grass lands intended for corn ; pasturing by pigs of grass or clover land intended for corn ; distributing a line of poisoned bran by means of a seed-drill. To prevent the caterpillars entering from a neighboring grass field, destroy them with a line of poisoned vegetable bait.

Sod Web-worms (Crambus spp.). — Gray or brownish caterpillars about one-half inch long, living in a silk-lined burrow in the soil at base of the plant. They thrive in grass land.

Preventive. — Early fall plowing of grass land intended for corn, or else plow as late as possible the next spring.

Army-worm. (Leucania unipuncta). — A cut-worm-like caterpillar, which normally feed on grass. When this food supply is exhausted, they migrate in numbers to other fields and attack corn, wheat, etc.

Preventive. — To stop the advance of the " army," plow deep furrows so the dirt is thrown towards the colony ; in the bottom of the furrow dig post holes into which the caterpillars will fall and where they may be killed with kerosene.

Chinch-bug (Blissus leucopterus). — A red or white and black sucking bug, three-twentieths of an inch long. Attacks wheat and corn in great numbers.

Preventives. — Clean farming to destroy suitable hibernating shelter. Stop the migration of the bugs from the wheat-fields into corn by maintaining along the field a dust strip ten feet wide in which a furrow and post-hole barrier has been constructed. This may be supplemented by a coal-tar barrier.

Grasshoppers {Acrididae). — Poison them with the Criddle mixture (p. 293).

Corn Ear-worm (Heliothis armiger). — A green or brownish striped caterpillar feeding on the corn beneath the husk. Three to six generations yearly.

Preventives. — Plant as early as possible, and still avoid a "set back " to the crop.

For insects infesting stored corn, see under Fumigation, p. 287.

Cotton. — Bollworm (Heliothis obsoleta).—This insect is also known as the corn earworm and tomato fruit-worm. The caterpillars are over an inch in length, and vary in color from greenish to dark brown.

Preventives. — Produce an early crop of cotton by planting early varieties, heavy fertilizing, early and frequent cultivation. Practice fall plowing, to destroy as many hibernating pupae as possible. Use corn as a trap crop. Plant it in strips across the field and time it so that the crop will be in silk and tassel about August 1. In areas infested by the boll weevil follow the recommendations given below. (Bureau of Entomology, U. S. Dept. Agric.)