Diabrotica barberi

Major pest on corn crops.

Mid-July to late September

Corn fields and adjacent areas

3 ⁄16″ to ¼″ long

This is a small leaf beetle.

The body is 3 ⁄16″ to ¼″ long, moderately elongated, and moderately flattened. When viewed from above, the head and most of the legs are clearly visible. Newly emerged adults are cream-colored to light brown, soon turning greenish-yellow.

The mouthparts project from the front of the head. The base of the antennae are close together, about level with the middle of the eyes. The antennae are flexible, and can project in various directions.

The pronotum is pale greenish-yellow and narrower than the elytra. It has a pair of depressions and a distinct lateral margin.

The elytra are pale greenish-yellow and hairless, with distinct, longitudinal, parallel ridges. They do not have stripes or spots.

When viewed from above, the leg segment closest to the body (femur) is greenish-yellow, never black or lined with black.

Roots of corn (Zea mays)

Mostly leaves and silk of corn (Zea mays); also plants of the Poaceae (grass), Asteraceae (aster), Fabaceae (pea), and Cucurbitaceae (gourd) families .

Adults emerge from mid-July to late August. They are most active at dawn and dusk. The female deposits its eggs in the soil within 6″ of the soil surface at the base of a corn plant. It may live up to 80 days and deposit up to 1,000 eggs.

The eggs overwinter in the soil. They hatch in early to late June. Young larvae feed on fine rootlets, older larvae invade the root core. They pupate in the soil within 4 to 6 weeks, and emerge as adults 5 to 10 days later.

Sources: 7.