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The corn root aphid attacks corn, other grasses, weeds, and cotton. The aphid is about the size of the head of a pin, and is bluish green in color. The insect obtains its nourishment by sucking the juices from the roots and it usually attacks the young plants. Infected plants are yellowish in color, wilt more readily than other plants, and don’t make a normal growth. When infestations are severe, the plants may die.
The corn root aphid is completely dependent on the brown ant for its continued existence. The root aphid lays its eggs in the fall, and the ants carry them to their nests where they are cared for during the winter. In the spring the eggs hatch, and the ants place the aphids on the roots of weeds. Later, when the corn becomes established, the root aphids are transferred to roots of this plant where they begin to feed. The aphid insects migrate to new corn fields; and here as before, they are placed on the roots by the ants. After the corn is harvested, the aphids continue their feeding on the roots of weeds of weeds and such corn plants as remain. The eggs usually are laid in October and November and are carried by the ants to their nests which are located below the plow furrow. The ants are compensated for this effort by obtaining a greater proportion of their food from the aphids.
How to control root aphid insect of corn?
Control of the corn aphid is accomplished largely by the use of good rotations and proper cultural practices. Damage is likely to be reduced when corn is grown immediately after a leguminous crop in the rotation rather than following itself or other grasses. Inasmuch as the insect feeds on roots of weeds or other grasses prior to attacking corn, clean cultivation is also effective for control. Destruction of the nests of the ants is probably the most effective and complete measure of control. Inasmuch as the nests are located quite deeply in the soil, effective control is obtained only by deep plowing followed by several deep cultivations with a disk or spring tooth harrow.