How to Manage Pests

Seasonal development and life cycle—Sphinx moth

Sphinx moths lay large green eggs singly on the upper surfaces of the outer grape leaves. Eggs hatch after 6 to 9 days. Immediately after hatching, a caterpillar eats a smooth round hole in the leaf and crawls through to the lower surface, where it continues to eat.

Caterpillars feed on grape leaves for about 25 days. They then make their way to the ground and construct a smooth-walled cell in which to overwinter as pupae. First-generation moths emerge during the first half of May. A second brood of moths, much more numerous than the first, appears in early July and the greatest damage is done in August. A generation is completed in about 55 days, and in some years there are three generations.