HEMLOCK WOOLY ADELGID - The insect called hemlock woolly adelgid (Adelges tsugae) main host is the Canadian hemlock (Tsuga Canadensis), however, many other hemlock species are attached by the pest. It is easy to recognize a hemlock woolly adelgid infestation because the eggsacs are present at the base of many of the needles.  The eggsacs look like small, dirty cotton balls.  The needles affected will discolor, dry out and eventually fall off.  Infested limbs often die within the first summer and whole tree succumb within 1 to 4 years.
Each hemlock woolly adelgid eggsac contains 50 to 300 eggs which begin to hatch in April and continues through June.  Once the eggs hatch, the new woolly adelgid "crawlers" search for a place to settle and feed on the hemlock branches.  Some of these crawlers develop into wingless adult females that stay on the tree and produce another generation.  Those that remain lay more eggs which hatch from June through mid-July.  These second generation adelgids will remain dormant until October and develop through winter.  Around February they are mature enough to lay eggs. The hemlock woolly adelgid was discovered in Connecticut in 1985, and since then, it has spread throughout several northeastern states.  The pests are tiny sap-sucking insects that feed on the branches of hemlock.  They locate themselves in the tight spaces where the needles attach to the twigs.  There, they feed on the hemlock sap killing the existing needles and interfering with the production of new needles.The most important part in controlling the woolly adelgid is to monitor carefully.  If an oil spray is used to kill the adelgids, it is only effective when the insects are in the crawler life stage.  Therefore, you must watch the insects around when you would expect to see the crawlers.  Once the crawlers are detected, the oil should be applied as throughly as possible.