Tree Pest Alert for September 10, 2012 – Hemlock woolly adelgid

Hemlock woolly adelgid (Adelges tsugae) or HWA, is a deadly pest of Eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) from Georgia to Maine and west to Tennessee and Kentucky.  Serious infestations can kill trees in 4 to 10 years.

What to look for:

The most distinguishing characteristic is the white woolly substance (hence the name) that covers the egg masses.  These woolly masses are visible from late fall to early summer.  You may also see yellowing needles, early needle drop, a decrease of new buds and new growth, and branch dieback.

What can you do about it?

The proper treatment strategy depends on if your tree is infested or if it is still healthy.  For healthy trees, Xytect works well to prevent future infesations, but for infested trees, Transtect is the product of choice because it works faster than Xytect and is more water soluble.  Hemlock woolly adelgid feed in the spring and the fall, so treatments must be timed accordingly.  Click here for more information on treatment timing for hemlock woolly adelgid.

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