How to Manage Pests

Seasonal development and life cycle—Cutworms

Cutworms that attack grapes overwinter in vineyard soil, trash, or grass clumps as immature larvae. Some move under the vine bark. When temperatures become warm in early spring, the larvae become active, emerging at night to feed on many kinds of plants. Feeding continues for about 10 days to 2 weeks during rapid bud and shoot growth. Larvae then return to the soil and hollow out cells or chambers to pupate. The pupal stage lasts 7 days or more and moths emerge from April through mid-May.

Eggs are laid singly or in groups on leaves, twigs, or stems. The egg stage lasts from 2 days to 2 weeks, and hatching larvae feed on low-growing vegetation. Moths resulting from this brood lay eggs to produce the late-summer larvae that overwinter.

Most cutworm species have one or two generations per year, but some have three or four generations and moths may be found from spring to fall.