Common Name: Cotton aphid or melon aphid
Scientific Name: Aphis gossypii Glover
Description:Adult aphids are winged or wingless, soft bodied yellow to dark green aphids 1/16 inch or less in size. Winged forms have a black head and thorax and hold their wings roof-like over the back of the body. There are many aphid species and they can be identified by looking at specific structures such as the projections on the end of the abdomen called cornicles and other features. Cotton and melon aphids are smaller and have shorter appendages than other common aphid species such as the green peach aphid, and on ornamental plants are one of the few common species that have a dark green (blue-green) form.
Life Cycle: Simple metamorphosis; parthenogenic. Wingless adults overwinter in protected areas such as in field debris and soil and feed on weed hosts. In the greenhouse, they can be active year-round. In spring winged females fly to suitable host plants and produce live young nymphs through a process called parthenogenesis. Nymphs develop through several instars before becoming mostly wingless adults in 4 to 10 days depending on temperature. Winged adults are produced when certain environmental conditions such as overcrowding, host plant decline or shortened day length occur. Adult aphids live for 3 to 4 weeks, each producing about 85 young. Many overlapping generations can occur annually. In greenhouses, up to 51 generations can be produced in one year.
Habitat and Food Source(s): This species feeds on a wide variety of plants (members of 25 plant families!) including asparagus, beans, begonia, catalpa, citrus, clover, cucurbits, cotton, ground ivy, gardenia, hops, hydrangea, okra, spinach, strawberries, tomatoes, violet and weeds. These aphids are also important vectors of some plant viral diseases.
Pest Status: One of the most common aphids on a wide variety of agronomic and horticultural plants; heavily infested plants can be injured or killed; medically harmless.
Damage: Feeding activities cause distorted growth, reduced growth, quality and yield. Excretion of the sugary fluid called honeydew by aphids is colonized by a black fungus called sooty mold, causing plants to become unsightly and stressed, because mold-coated leaves are shielded from sunlight needed for photosynthesis. Numerous cast skins from aphid development are also unsightly.
Management: See Vegetable IPM.
Literature: Carter et al. 1980; Drees 1993.