Click for image of

adult (Yellow Phase)

by

Iowa State University

Adults:
The adult bean leaf beetle is about 1/4 inch (6 mm) long. It varies in color from light yellow to tan when newly emerged from the pupal stage, to green or even sometimes a red when mature. Each wing cover has four black spots and a dark stripe along the edge, although these stripes are occasionally absent. There is also a black triangle on the forward margin of the wings.

Click for image of

adult (Red Phase)

by

Iowa State University

Eggs:
The eggs are lemon shaped, about 1/32 inch (0.85 mm) long, reddish-orange in color and laid in clusters at the base of the plant. The female will lay up to 1000 eggs but about 250 is the norm. The eggs hatch within 2-3 weeks depending on temperature.

Larvae:
The larva is a slender white grub with a segmented body about 1/3 inch (10 mm) long. The body has a dark spot at both ends and very short legs near the head. The larva spends all of its life stage feeding underground until pupation.

Pupae:
The larva pupates underground forming a white exposed soft body about 1/4 inch (5 mm ) long. The adult beetle emerges about one week later.