Eric Day, Insect Identification Lab Manager, Department of Entomology, Virginia Tech
of cucurbits. They cause four types of damage: seedling destruction, flower and foliage damage, root feeding, and transmission of bacterial wilt disease. Damage from cucumber beetles starts in the spring with feeding by adults on the seedling stage of the cucurbits. The beetles feed on newly emerged cotyledons and stems, and they have been reported to go below ground level and feed on plants as they emerge.
Adults lay eggs in the soil near the seedlings and larvae soon hatch and begin feeding on roots of the cucurbits. Larvae chew holes and tunnel into the roots. Damage by the larvae, except under dry conditions, is usually considered minor. The first generation of adults emerges in late June and early July to feed on the foliage and flowers. Feeding damage by cucumber beetles to foliage is usually very minor, but severe feeding on flowers can result in poor fruit set. The second generation emerges in September and October.