One common potato pest is the aphid, identified by tubular structures on its back called cornicles. Another common potato pest is the cutworm, which curls up into a distinguishing C-shape when disturbed.
Aphids are one of the most well-known potato pests. Aphids caused the Irish potato famine of the 1840s. Located throughout the world, aphids range from 1 to 10 millimeters in length and have pear-shaped bodies with long antennae. They have two tubes called cornicles projecting outwards from their rear ends. Aphids are wingless and usually appear in large populations rather than small groups.
Cutworms are the larvae of a number of moth species. They eat the stems of potato plants and begin feeding at dusk. Cutworm larvae are earthen-colored and often display stripes or spotted patterns. They grow up to 2 inches in length and are smooth-bodied worms. Signs of cutworms include damage to tubers and foliage.
Flea beetles are potato pests that feed on potato stems, cotyledons and foliage and cause irregular rounded pits in potato leaves. This characteristic "shothole" appearance to foliage is key to identifying flea beetles. They range in size from 1/16 to 1/8 inch long. They appear in a variety of colors including blue, bronze, black, brown and metallic gray. Flea beetles have large back legs that allow them to jump when disturbed.