Traps should be placed around the perimeter of the vineyard and should be at least 100 feet apart. Traps should be checked weekly for moths and the pheromone caps replaced monthly to obtain accurate trap information. Each vineyard location is unique and growers should not rely on trap data from other vineyards to time insecticide sprays. Scouting vineyards is necessary to determine grape berry moth activity. Scouting for eggs is not productive.
Adults are unlikely to be seen unless caught in pheromone traps.
A trained eye can recognize them flying in the late afternoon. Signs of larval feeding are the easiest to find. Examine fruit clusters after bloom for evidence of webbing in the clusters. This will give an indication of Initial numbers of overwintering moths. Later examine fruit clusters for stings indicating larvae entry.