cutworms are large, smooth caterpillars measuring 30 to 40 mm when
fully grown. The head capsule is usually dark and the body is dull
gray-brown, marked with dots or stripes. The larvae overwinter in
the soil of the vineyard floor and become active in spring when vine
buds begin to expand. Larvae feed on young buds at night, hiding in
the soil beneath the vines during the day. Feeding may injure buds
or remove them entirely. Cutworms are mainly a pest in areas with
sandy soils and in vineyards with weeds under the vines. Injury is
often worse in years when cool temperatures slow bud development.
a history of cutworm damage should be scouted regularly during bud
expansion, particularly after warmer nights. Once shoot expansion
begins, vines are no longer at risk.
damage to an expanding bud.
Photo: Tom Zabadal