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The adelgid is a relative of aphids that was accidentally imported form Asia. It feeds mainly on Canadian and Carolina hemlock. A visible, cottony wax is produced by the female insects in September and October. The following spring, the female lays her eggs under the cover of the waxy material. In April through June, the eggs hatch and small reddish brown crawlers begin to feed on the sap of new twigs. In only a few weeks, the juveniles mature into grey-coloured adults. Some of the adults have wings and fly to other nearby trees, while others remain on the original tree to lay new eggs and create a new generation. The second generation hatches in late July, becoming dormant in late summer, and then begins to feed again in the fall. As their sap is sucked out by the adelgid, the branches begin to die, which can result in entire trees dying within a few years.
The adelgid is protected by its waxy coating much of the time, but it is susceptible to insecticides when crawlers are active in the spring and the fall. To control the insect, it is best to spray with Bug Buster when they are in the crawling state. If you live in an area where adelgids are present, it is also important to regularly monitor trees, especially Hemlock trees, so that treatments can be applied as early as possible. For trees that are too tall to spray, treat them with Once-A-Year Insecticidal Drench w/Merit, in the early spring.