Winter moth

Winter moth larvae emerge in early spring from egg masses, burrowing into expanding buds and feeding on new leaves for six weeks. You will see small, hole-ridden leaves and defoliation by late May in western Washington and British Columbia. This European invasive causes significant damage to oaks, apples, and maples. Adults fly in late fall and early winter.

Monitor for egg hatching when daytime highs reach approximately 50 degrees Fahrenheit (10 degrees Celsius). Spray Bt when buds break and larvae emerge, then repeat every seven to ten days. Wrap tree trunks with sticky bands in October to intercept flightless females. Encourage native parasitoid wasps and Calosoma beetles.