Crawlers can be carried by birds, larger insects, and the wind. The whitish, oval eggs under the dead female hatch in late May, about the time that common lilac is in bloom. Reported in Vermont. Worst on Concord variety. Eggs are deposited in late spring under the female.
Hatching is in early summer and the crawler stage moves to the foliage.
In late summer, they move back to rough bark where they settle for the winter. Crawlers can be moved by wind and birds. Overwinters as nymphs on the twigs. Reported in Vermont. Worst on the Concord variety.