Some of the more common aphids include the green peach aphid, melon aphid, tulip tree aphid, giant bark aphid, white pine aphid and rose aphid. Description Aphids constitute a large group of small, soft-bodied insects. They may measure up to six mm in total length. Aphids have piercing-sucking mouth parts that enable them to remove plant fluids from a host. The cornicles secrete a defensive fluid which warns aphids of predators and other enemies.
Aphids vary in color from green, yellow, red, purple, brown, or black.
The life history of many aphids is complex and unusual. Enormous populations of aphids can be built up in a short period of time. Although considerable variation occurs between species, a typical life history is described as follows. Aphids generally over winter as fertilized eggs. With the approach of spring weather, the eggs hatch into nymphs which rapidly mature into wingless females.