Seasonal development of the navel orangeworm. Appearance of broods and developmental times vary with temperature. Two full generations (1, 2) and a partial third generation (3) are produced during the season. A portion of the second generation and the third (overwintering) generation of larvae enter sound nuts after husk split (shaded area starting about mid-August). Time of husk split varies with cultivar and temperature. Credit: Integrated Pest Management for Walnuts, Third Edition. UC ANR Publication 3270.
