County News
Hemlock Woolly Adelgids
This news item expired on 10/31/2006, so the information below could be outdated or incorrect.
Hemlock woolly adelgids are now widespread throughout western North Carolina. If you have infested hemlock trees, fall is a good time to treat with organic sprays or systemic insecticides.
First examine your trees. (Only hemlocks are affected.) Look for small wads of white cottony material along the twigs, at the base of the needles. There is no need to treat trees that are not affected.
If trees are small enough to spray, horticultural oil or insecticidal soap can do a good job if you get good spray coverage to coat all the insects. Do not allow spray to drift onto surface water.
Large trees may be treated with systemic insecticides containing imidacloprid (Merit, Bayer Advance Garden Tree and Shrub Insect Control). If the tree is not close to a stream, a soil drench can be applied by digging a shallow trench one foot from the trunk. Follow label directions carefully for calculating mixing and application rates.
Trees that can not be treated with a soil drench because of proximity to a stream or sloping or rocky soil, can be treated by trunk injections. This method would need to be handled by a professional arborist.
For more information on Hemlock Woolly Adelgids:
- BCTV Streaming Video: Hemlock Woolly Adelgid
- Recommendations for Hemlock Woolly Adelgid Control in the Landscape