The term “potato bug” often causes confusion, as it colloquially refers to several distinct, unrelated creatures, including insects and crustaceans. This article details the visual characteristics of the most frequently identified “potato bugs” for accurate identification.
The Colorado Potato Beetle
The Colorado Potato Beetle (Leptinotarsa decemlineata) is the most recognized “potato bug” due to its association with potato plants. Adult beetles are oval-shaped and robust, measuring 6 to 11 millimeters (about 1/4 to 1/2 inch) long. They have a bright yellow or orange body with ten prominent black stripes down their wing covers (elytra). Their small head often has black markings, and the area behind it (prothorax) is yellow-orange with black spots.
Larvae have identifying features. They are reddish-orange, plump, and humpbacked, with a black head and distinct black spots in two rows along their sides. Larvae can grow up to 15 millimeters (0.6 inches) and are commonly found feeding on potato plant leaves.
The Jerusalem Cricket
The Jerusalem Cricket (Stenopelmatus fuscus and related species) is also called a “potato bug,” especially in the western United States. This large, flightless insect has a robust, cylindrical body, ranging from yellowish-brown to reddish-brown, often with black and whitish stripes on its abdomen. Adults measure 30 to 75 millimeters (about 1 to 3 inches) long.
Its most striking feature is a very large, rounded head that appears bald and can have distinct, almost human-like features, including large, dark, widely spaced eyes. They have strong mandibles (jaws) capable of inflicting a painful bite if threatened. Their legs are thick and spiny, especially the forelegs, which are adapted for digging. Unlike many other insects, Jerusalem Crickets lack wings.
Sowbugs and Pillbugs
Sowbugs (family Porcellionidae) and Pillbugs (family Armadillidiidae) are terrestrial crustaceans, not insects, often mistaken for “potato bugs.” Both are small (6-19 mm or 1/4-3/4 inch), with oval, segmented, usually grayish bodies and seven pairs of legs, distinguishing them from insects (which have three).
A key visual difference distinguishes sowbugs from pillbugs. Sowbugs have a flattened body and two prominent tail-like appendages (uropods) at their rear; these prevent them from rolling into a ball when disturbed, causing them to scurry away. Pillbugs, in contrast, have a smoother, more domed appearance and lack these structures. Their flexible, segmented bodies allow them to curl completely into a tight, protective ball, earning them the common name “roly-poly.” Both prefer damp environments, often found under rocks, logs, or leaf litter.