Hemlock trees at risk due to invasion of exotic pest

New York State Department of Environmental Conservation (DEC) Commissioner Erin M. Crotty and State Agriculture Commissioner Nathan L. Rudgers have called for residents of Monroe County to watch for an exotic tree pest that has infested a new area of New York state.

The hemlock woolly adelgid is a tiny insect that sucks sap and nutrients from hemlocks, eventually killing the trees. Hemlock woolly adelgids, which are native to Asia, have been a serious problem in southeastern New York for more than a decade, but were only recently discovered at two locations near Rochester.

"The discovery of the adelgid in a new area is cause for concern, and we ask the residents of Monroe County to please assist us in targeting these pests so that we may help to contain the problem and preserve the health of hemlock trees throughout New York state," said Commissioner Crotty.

State Agriculture Commissioner Nathan L. Rudgers said, "The importance of hemlock trees in the urban and forest environment cannot be overstated. It is one of the most common backyard species planted by homeowners and one of the most cultivated landscape tree species. The Department of Agriculture and Markets will continue to work cooperatively with DEC to make homeowners, farm woodlot owners and the state's 2,400 nursery establishments aware of this pest."

The presence of hemlock woolly adelgids on trees in the Town of Brighton, Monroe County, was first confirmed by Cornell Cooperative Extension. DEC foresters, officials from the State Department of Agriculture and Markets, and volunteer tree-care professionals responded to the initial report by examining more than 600 hemlock trees in surrounding areas. Another infested location was later discovered a few miles away in the Town of Irondequoit.

The infestations have been determined to be small and isolated, but there is risk of spreading. In forested conditions, treatment of infestation become much more difficult and can lead to widespread decline of hemlock trees, as seen during the last decade in parts of the Catskills and Hudson Valley.

The State Department of Agriculture and Markets will identify nurseries and plant dealers that grow hemlock for sale to ensure they are familiar with the hemlock woolly adelgid in an effort to monitor incoming stock. Homeowners and tree-care professionals can help by looking for the distinctive egg masses of hemlock woolly adelgids on Eastern or Carolina hemlocks. The egg masses are white and woolly in appearance, resembling the tips of cotton swabs, and are present throughout the year at the bases of the needles. Ornamental trees can be treated with insecticides or horticultural oil to control the pest. Infested trees should be reported to the nearest DEC office so individuals may receive information on the safest and most effective methods of treatment.

Hemlock trees can be recognized by their dark green needles with two silvery lines on the underside, without sharp points, and small cones that hang down from the branch tips. Quarantines regulating the movement of hemlock have already been established in Maine, Vermont and New Hampshire.

Anyone who sees the insect on hemlock trees in Monroe County is asked to call the DEC forestry unit in Avon, Livingston County at 585-226-5466. Nurseries and plant dealers are asked to call the State Department of Agriculture and Markets at 1-800-554-4501. Further information on pesticides for controlling hemlock woolly adelgids can be obtained from the Cornell Cooperative Extension Garden Help Line at 585-473-5335.