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The adelgid is a relative of aphids and was accidentally imported form Asia. It feeds mainly on Canadian and Carolina hemlock. The 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 the new, young twigs. The juveniles mature fast into grey coloured adults in only a few weeks. 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, become dormant in late summer and then begins to feed again in the fall. As the branches are attached and their sap is sucked out by the adelgid, branches begin to die and entire trees can die within a few years.
The adelgid is protected by its waxy coating much of the time but is susceptible to insecticides when crawlers are active in the spring and the fall. It is best to spray with Bug Buster to control the insect when they are in the crawling state. It is also important to regularly monitor trees especially Hemlock trees, if you live in an area where adelgid are present, so that treatments can be applied as early as possible. For trees that are too tall to spray, treat with Once-A-Year Insecticidal Drench w/Merit in the early spring.