Green Peach Aphid

Green Peach Aphid by Eugene Nelson
Green peach aphid is a vector for more than 100 viruses on a wide variety of crops. Photo: Eugene Nelson

Green peach aphid (Myzus persicae) feeds on hundreds of host plants in more than 40 plant families. Vegetable hosts include artichoke, asparagus, bean, beets, broccoli, Brussels sprouts, cabbage, carrot, cauliflower, cantaloupe, celery, corn, cucumber, fennel, kale, kohlrabi, turnip, eggplant, lettuce, mustard, okra, parsley, parsnip, pea, pepper, potato, radish, spinach, squash, tomato, turnip, watercress, and watermelon.

Identification
In warmer climates like Florida, the aphids do not seek out overwintering hosts, but persist as active nymphs and adults on hardy crops and weeds throughout the winter months.

Nymphs initially are greenish, but soon take on a yellowish hue, resembling adults. The wingless (apterous) aphids are yellowish or greenish in color. They measure about 1.7 to 2 millimeters (mm) in length. A medial and lateral green stripes may be present. The cornicles are moderately long, unevenly swollen along their length, and match the body in color. The appendages are pale. The nymphs that give rise to winged females (alates) may be pinkish.

Winged aphids have a black head and thorax, and a yellowish green abdomen with a large dark patch dorsally. They measure 1.8 to 2.1 mm in length. Green peach aphids can attain very high densities on young plant tissue, causing water stress, wilting, and reduced growth rate of the plant. Prolonged aphid infestation can cause appreciable reduction in yield of root crops and foliage crops. The major damage caused by green peach aphid is through transmission of plant viruses. Nymphs and adults are equally capable of virus transmission. More than 100 viruses are transmitted by this species.

Survival And Spread
As aphid densities increase on host plants, winged forms are produced, which then disperse to summer hosts. Winged green peach aphids attempt to colonize nearly all available host plants. They often deposit a few young and then again take flight. This highly dispersive nature contributes significantly to their effectiveness as vectors of plant viruses.
Development can be rapid, often 10 to 12 days for a complete generation, and over 20 annual generations per year may occur in mild climates.

Broadleaf weeds can be very suitable host plants for green peach aphid. Common and widespread weeds, such as field bindweed, lambsquarters, and redroot pigweed, often are cited as important aphid hosts.

Management Methods
Because some of the virus diseases transmitted by green peach aphid are persistent viruses, which require considerable time for acquisition and transmission, insecticides can be effective in preventing disease spread in some crops.

Hundreds of natural enemies have been recorded, principally lady beetles, flower flies, lacewings, parasitic wasps, and entomopathogenic fungi. Softer pesticides including insecticidal soaps like M-Pede (potassium salts of fatty acids, Gowan Co.), nicotinoids like Admire, Provado (imidacloprid, Bayer CropScience), Assail (acetamiprid, United Phosphorus Inc.), and others including Beleaf (flonicamid, FMC Corp.), Movento (spirotetramat, Bayer CropScience), and Fulfill (pymetrozine, Syngenta) will provide good control and help reduce impact on beneficials.

by Gene McAvoy, Regional Vegetable Extension Agent IV, University of Florida/IFAS