Authors: Dr. Randy Hudson, Dr. David Adams, University of Georgia
The green peach aphid is soft-bodied and pear-shaped, ranging from 1.6 to 2.4 mm long with piercing-sucking mouthparts. Aphids are usually wingless. The wingless green peach aphid adult is pale-yellow to green. In the fall, color may range from pale- to dark-green to pink or red. The winged migrant form has a yellowish green abdomen with a dark dorsal blotch. Both forms have a pair of tailpipe like appendages known as cornicles. Nymphs are slightly smaller than the adult but similar in shape. They are pale yellow-green with three, dark lines on the abdomen.
The green peach aphid infests a wide range of plants. Some important hosts include cabbage and related cole crops and leafy greens, tomato, tobacco, potato, spinach, pepper, eggplant, legumes and others.
Green peach aphids extract sap from plants and excrete a sweet sticky substance known as honeydew. Black sooty mold grows on the honeydew and, though not directly harming the plant, may block out sufficient light to reduce yield. The green peach aphid transmits several viral diseases including several important mosaic viruses on squash and other cucurbits.
Adults pass the winter on greens and other wild hosts. Winged forms migrate to other hosts in late spring. During these migratory flights, aphids may spread virus diseases from infected volunteer plants and weeds to healthy crops. In Georgia, the aphids are nearly all females. Successive generations of females, mainly wingless, are produced throughout the year. Winged migrants develop whenever overcrowding occurs or food becomes scarce. Many generations may occur per year.
In many crops, natural controls often can regulate the population below economic impact thresholds. Many predators, fungus diseases, high temperatures, hard rains and damp weather reduce aphid populations. Insecticides are the second choice for controlling aphids. Oil sprays are used to prevent the spread of virus diseases in squash.