The SLELO region is no longer the only region in NYS to have not found HWA.

While conducting early detection searches for hemlock woolly adelgid over the last several weeks, the SLELO Early Detection Team, Robert Smith and Brittney Rogers, have now observed three separate populations of hemlock woolly adelgid (HWA)in southwest Oswego county. Photographs from each site were confirmed to be HWA by Mark Whitmore, a Forest Entomologist with the Department of Natural Resources at Cornell University. This marks the first confirmed observations of HWA within the SLELO PRISM region- our region encompasses Oneida, Oswego, Jefferson, Lewis, and St. Lawrence counties.

Responding to HWA in SLELO

SLELO is collaborating with the NYS Department of Environmental Conservation, Oswego County Soil and Water Conservation District, affiliated land managers and the New York State Hemlock Initiative to develop a strategic response to provide guidance and assistance to the landowners and managers of the infested sites.
It is important to note that the land owners/managers are under no obligation to treat infested hemlock trees, however, treatment is encouraged for two reasons; first, hemlock trees provide essential services that are vital to forest health; and second, treatment will reduce the rate of spread of this invasive forest pest into other parts of our region. Treatment may include a combination of insecticides and biological controls. You can learn about treatment options at the New Your State Hemlock Initiative- NYSHI website.
A delimiting survey was conducted at the initial site by SLELO PRISM staff, the Oswego County Soil and Water Conservation District, the Youth Bureau and numerous volunteers. At this 40 acre site, over 1,100 hemlocks were surveyed with just over 30% visibly infested. It is believed that this population has likely been established for several years as stem mortality has been observed. More surveys are being planned in collaboration with the NYS DEC and SLELO partners. More information on this response will be released as plans are finalized.

Survey Suggestions

Experts have suggested that the more likely area for HWA to spread in the SLELO region is along the eastern Lake Ontario shoreline because of the moderated temperatures adjacent to the Lake. Landowners and land managers in Oswego county and throughout the eastern Lake Ontario region are encouraged to check their hemlock trees for signs of hemlock woolly adelgid. For those participating in hemlock woolly adelgid survey efforts, hemlock stands located along the eastern Lake Ontario shoreline should take survey priority.

Signs to look for include: lack of bright green foliage on the tips of hemlock branches in the spring, needle loss and dead branches within the tree crown, and the presence of white woolly masses in addition to black insects with white fringe, both of which will be nestled along hemlock branches where the needles connect to twigs. 

If you think you have found HWA in the SLELO region, be sure to note the location of the observation, take clear photos of the infestation and email the information to the SLELO PRISM Terrestrial Coordinator, Robert Smith at or contact the NYS DEC Forest Pest Hotline at 1-866-640-0652 or report the observation via

If you would like to get involved in surveying for HWA in the SLELO region join our invasive species Volunteer Surveillance Network

An Interesting Find

The photo below was taken of a hemlock branch at one of the sites. If you look closely at the photo, there is one woolly mass and multiple sesame-seed-sized black insects with white fringe nestled along the branch where the needles connect. The HWA without the woolly mass (small black insects) most likely didn’t awake from aestivation, which is a resting phase that occurs in the summer.
Considering that we found branches that have both active HWA with white woolly masses, and non-active nymphs without white masses, it is important to look at branches with a magnifying glass and search for signs of non-active nymphs in addition to searching for the white masses of HWA on the hemlocks you survey. 
You can learn more about the phenology of hemlock woolly adelgid on the NYSHI website

Photos From Our HWA Delimiting Survey