The European grape berry moth (Lobesia botrana) and the American grape berry moth (Paralobesia viteana, previously Endopiza viteana) are similar in appearance and cause similar damage to grapes.
The former was first reported in Napa County, California, in 2009 and reportedly eradicated from the state by 2016 following a statewide trapping and management program. The American grape berry moth, native to eastern North America, is now found in parts of western Colorado.
The slender larvae reach a maximum size of 1-1.5 cm and are green to light purplish with a darker contrasting head and first thoracic segment.
The adult moths are generally less than 0.75 cm long and of a medium brown colour, mottled in patches of lighter or darker brown, dark grey or blue depending on the species.
Both are best identified by the damage caused by larvae feeding on flowers and fruit.
Larvae of the first generation feed on developing buds, flowers and small berries and produce a significant amount of webbing. Larger first and second generation larvae burrow into and feed on the fruit, leaving hollowed out skins and seeds.
Grape bunches become contaminated with frass and webbing and are subject to fungal infections.
European Grapevine Moth, on the University of California Statewide Integrated Pest Managament Program website, in the Invasive and Exotic Pests section
