Biology and Management of Cutworms in Washington Vineyards

Conversely, sites with small numbers of Cutworms sometimes sustained major bud damage. This appeared to be related to ground cover presence/absence and/or type, but was also, in view of the rearing data, a consequence of most ground-dwelling species preferring to remain on the ground and not climb up grapevines. In vineyards where broadleaf weeds were common (> 25% of cover), Cutworm damage was low (0-6% of buds damaged). In vineyards that had no ground cover, bud damage of up to 12% was recorded with Cutworm abundance ranging from 6-10 per hour search. In vineyards where grasses were dominant, bud damage of up to 18% was recorded even though Cutworm abundance did not exceed 5 in an hour’s search. Thus, even though most Cutworm species in WA vineyards prefer to feed on broad-leaved weeds etc, it is likely they will climb grapevines if sufficient food is not available on the ground. Potential Cutworm predators were abundant in many vineyards especially those with diverse ground covers. Carabid beetles were the most common predators. Determining the identity of adult Cutworm species occurring in south-central Washington vineyards during July-October through establishing and monitoring feeding attractant-based traps is a crucial tool in containing the pest.