Spotted Cucumber Beetle

The spotted cucumber beetle is a common leaf beetle in the family Chrysomelidae, subfamily Galerucinae, easily recognized by its pale yellow-green body dotted with a dozen black spots. It is one of the most widespread and frequently encountered beetles in North American gardens and farmland.

Its larval stage, known as the southern corn rootworm, feeds underground on the roots of corn and other grasses, while the adult stage feeds above ground on the leaves, flowers, and fruit of cucurbits and many other plants, giving the species a broad host range across its life cycle.

As a generalist feeder present in large numbers, the spotted cucumber beetle is a familiar and ecologically significant insect in agricultural landscapes, interacting with a wide variety of cultivated and wild plants throughout its range.

• Adult: 5–7 mm, elongated oval body, pale greenish-yellow overall with eleven to twelve distinct round black spots arranged across the elytra.
• Head and antennae are black, and the legs are typically dark as well, contrasting with the pale body.
• Antennae are moderately long and thread-like.
• Lookalikes: closely related to the striped cucumber beetle, but distinguished immediately by its spotted rather than striped elytra pattern; both share a similar body shape and size.

Widely distributed across the United States and into parts of Canada and Mexico, found in vegetable gardens, row crop fields, meadows, and disturbed open ground wherever cucurbits, corn, beans, or many other host plants grow. Adults are active from late spring through fall, with peak abundance in mid to late summer.

Adults feed on the leaves, flowers, and developing fruit of cucurbits and a wide range of other garden and field plants, chewing irregular holes in foliage and petals. Larvae, called southern corn rootworms, live in the soil and feed on the roots of corn and various grasses. As a highly mobile and generalist feeder, this beetle interacts with numerous plant species and is considered a common agricultural pest across much of its range.

Females lay eggs in the soil near the base of host plants, and the larvae hatch and burrow down to feed on roots for several weeks. After completing larval development, they pupate in the soil, and adults emerge to feed above ground and mate. The species can produce one to several generations per year depending on climate, with adults overwintering in leaf litter or soil in milder regions.