Corn Leaf Aphid, Rhopalosiphum maidis (Fitch)

PLANTS ATTACKED: Corn, broomcorn, small grain, grain sorghum and other plants of the grass family.

DESCRIPTION: The corn leaf aphid is greenish blue. Both winged and wingless forms prevail especially during the summer. The wingless female is somewhat ovate in form and about 1/12 inch long. She has black legs and antennae.

LIFE HISTORY: The aphid spends the winter in the adult stage. Activity and reproduction of the aphid may be continuous throughout the winter in extreme South Texas. The insect reproduces by giving birth to living young, and the offspring do not wander from their place of origin. A life cycle may be completed within a few days. There are several generations annually.

DAMAGE: The young and adults suck the plant juices, which frequently cause yellowish mottling on the leaves. The insect commonly is found deep in the whorl of the middle leaf, in the heads and on stems of various grass crops. It excretes honeydew in which fungi often grow. Heads of grain sorghum and small grain, and ears of corn affected by these fungi may become "sooty."

BIOLOGY:Females give birth to living young without mating and a generation can be completed in about a week. In Texas the insect is active throughout the winter. These aphids generally infest the whorl of sorghum plants. Their densities often decline as plants enter the boot and heading stage. Panicles may become heavily infested with cornleaf aphids while the grain is immature.