Grape Colaspis Egg - The smooth, white to yellow egg is about 0.6 by 0.25 mm.
Larva - Measuring up to 7 mm long, the grayish-white or tan larva has a dark brown head and prothoracic shield. It is stout and grub-like in form with three pairs of legs near its head and fleshy appendages on the abdominal segments.
Pupa - Whitish at first, the 4 mm-long pupa gradually darkens.
Host Plants - The adult beetles are very general foliage feeders, and in most cases, the larvae feed on roots of the same plants. Soybeans and lespedeza seem to be preferred food plants of the adults. Other hosts (of both larvae and adults) include grape, snap bean, red and white clover, strawberry, corn, timothy, okra, beet, and the weeds dock and smartweed.
Damage - Colaspis beetles consume foliage but rarely do any appreciable damage. When large populations of larvae develop, however, damage much like that done by nematodes occurs. Larvae eat lateral roots and the soft outer tissues of underground stems. This injury becomes evident above ground as areas of yellow, stunted plants develop.
Life History - The grape colaspis overwinters in the soil as third through eight instar larvae. In spring, feeding and development resume. Most larvae pupate within 3 cm (1.5 inches) of the soil surface for a period of 3 to 7 days in June. By late June, most adults have emerged. The beetles mate several times and feed on legumes for 3 to 5 days before eggs are laid. Each female deposits approximately 75 eggs, usually in masses of about 36, near the roots of food plants. In North Carolina, only one generation is completed each year.