Green Peach Aphid
Myzus persicae (Sulzer), Aphididae, HEMIPTERA


DESCRIPTION

Adult - This soft-bodied, pear shaped insect is usually wingless and ranges from 1.6 to 2.4 mm long. The wingless female is pale yellow to green. The winged midgrant form has a yellowish-green abdomen with a dark dorsal blotch. Both forms have a pair of tailpipe-like appendages known as cornicles.

Egg - No egg stage occurs in North Carolina.

Nymph - Slightly smaller than the adult but similar in shape, the nymph is pale yellow-green with three dark lines on the abdomen.


BIOLOGY

Distribution - The green peach aphid is a cosmopolitan species.

Host Plants - The green peach aphid infests a wide range of plants. Some important hosts include cabbage and related cole crops, dandelion, endive, mustard greens, parsley, turnip, tomato, tobacco, potato, spinach, pepper, beet, celery, lettuce, and chard.

Damage - Green peach aphids extract sap from plants and excrete a sweet sticky substance known as honeydew. Black sooty mold grows on honeydew and, though not directly harming the plants, may block out sufficient light to reduce yield. Weakened plants become susceptible to secondary disease and may be inoculated with viruses carried by aphids. Among the virus diseases transmitted by green peach aphids are potato leaf roll, potato virus Y, beet mosaic, beet yellows, and lettuce mosaic.

Life History - Adults pass the winter on greens and wild hosts such as cabbage, collards, turnip, wild mustard, and dock. 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 crop plants. Movement between host plants continues through summer and fall.

In southern states, 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. This type of development (all females, no males or eggs) occur as far north as Tennessee and Maryland. Many generations are produced each year.


CONTROL

Lady beetles and their larvae, lacewing larvae, syrphid fly larvae, and stilt bugs all feed on aphids. Fungus diseases, high temperatures, damp weather, and hard rains also reduce aphid populations.

Cultural practices are helpful in avoiding aphid infestations. Winter host plants (collards, mustard, dock, turnip) in the vicinity of seed beds should be destroyed before plants begin to come up. The purchase of certified seed from areas free of virus is also a good preventative measure.

A number of insecticides are available to control aphids on a wide variety of crops. However, repeated applications of certain carbamate insecticides within intervals of a week or less are frequently conducive to aphid buildups. For specific chemical recommendations, consult the current North Carolina Agricultural Chemicals Manual.

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