Forest Service Vaccinates Trees to
Protect Against Hemlock Woolly Adelgid

MORGANTOWN, WVa— State and Private Forestry officials with the USDA Forest Service will vaccinate hemlock trees with the insecticide imidacloprid Tuesday and Wednesday in the Blue Bend Recreation Area of the Monongahela National Forest.
 
The process involves drilling small holes near the base of the tree and attaching an injection port.  The actual injection process can take up to an hour to complete depending on tree size and other factors. The injected insecticide will disperse throughout the tree, killing the adelgid as it feeds.  Imidacloprid protects hemlock trees for up to 3 years.

 “The use of insecticides provides short-term protection to high-value hemlock trees such as those found in popular campgrounds and recreational areas.  We are also releasing predatory beetles elsewhere on the forest that hold promise as a long-term regulator of adelgid populations,” said Forest Service entomologist Rick Turcotte.  “Chemical treatments are essentially a stopgap measure until the predators become established in sufficient numbers at which they can keep the adelgids in check.”

The eastern hemlock is a critical component of native trout habitat and does not have an ecologically equivalent tree species that can take its place. It grows in dense forests, providing shelter when harsh weather conditions exist. Research presented at a hemlock woolly adelgid symposium in 2002 showed that brook trout populations were three times greater in hemlock-shaded streams than in streams bordered solely by hardwoods. Research shows that hemlock-shaded streams have lower summer temperatures and are less likely to dry up. Hemlocks maintain aquatic habitat integrity by regulating streamflow and moderating water temperature.

Treating trees with imidacloprid and releasing predatory beetles are two tools the Forest Service is using in its ongoing effort to protect hemlock trees from the hemlock woolly adelgid.

For more information on protecting hemlock trees, go to http://www.na.fs.fed.us/fhp/hwa.  A photo vaccination process is available at http://www.na.fs.fed.us/nanews/archives.shtm.

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