Adult - Very similar in appearance, these two aphid species are pale green and, most commonly, wingless. Both species have a pair of short swollen cornicles (tailpipe-like appendages) on their abdomens. The cornicles of the cabbage aphid are shorter than the turnip aphids. The cabbage aphid is 2.0 to 2.5 mm long and covered with grayish waxy coat. The turnip aphid has no such covering and is 1.6 to 2.2 mm long.
Damage - Aphids cluster on the underside of leaves and suck sap causing infested foliage to curl, wilt, or become distorted. Some infested plants are soon killed; others grow slowly, are stunted, and produce small unmarketable heads.