They are especially common in weedy areas or wind breaks and will fly readily when disturbed. The blueberry spanworm spends the winter as an egg in the litter near the base of blue-berry plants. Eggs may begin to hatch and larvae start feeding on developing buds as early as April and continue to feed on blue-berry leaves, buds, and blossoms until late June or early July. Fully grown larvae move into the litter, where they remain as pupae. At this stage and time, they do not feed.
Moths begin to emerge in about two weeks.
Adults can first be seen in the field in early to mid-June. Some moths may still be present until late July. Eggs laid by the moths do not hatch until the following spring. Damage and Economic Importance Infestations of blueberry spanworm may be confined to isolated areas or damage may be widespread. Large numbers of spanworm larvae may completely defoliate areas in both crop and pruned fields.