Slugs may cause peak damage to seedlings during cooler weather. Eggs hatch and young nymphs move to feed on new growth. Galls are initiated. Peak flights typically occur at this time. Check infested plants.
Small nymphs are present in chambers of the gall.
Monitor infested trees. Larvae chew leaves of current and gooseberry. Damage starts in the interior of shrub. Most new transmission of Dutch elm disease occurs at this time. Monitor flights with pheromone traps.