OSWEGO — The Eastern Lake Ontario region’s first known infestation of the invasive hemlock woolly adelgid has been confirmed in Oswego County.
An invasive species early detection team conducted searches in the southwest part of the county over the last several weeks, observing three separate populations of HWA. The work was done through the St. Lawrence-Eastern Lake Ontario Partnership for Regional Invasive Species Management, or SLELO PRISM.
HWA was previously recorded in the Adirondacks — in 2017 at Prospect Mountain, at the southern end of Lake George in Warren County, and in 2020 on state Forest Preserve lands near the Glen Island camp area in Washington County. The Warren County HWA populations have since been eradicated, and a state Department of Environmental Conservation treatment plan was initiated at the Glen Island site in the fall.
Eight regional PRISMS operate throughout the state, developing invasive species surveillance programs and management strategies based on priorities specific to each region. The SLELO PRISM is responsible for leading invasive species work with other environmental and conservation organizations in Oneida, Oswego, Jefferson, Lewis and St. Lawrence counties.
Native to East Asia, HWA damages hemlocks by feeding on tree tissue and nutrients through a thin, tubed mouthpiece. The wounds inflicted by the mouthpiece lead the tree to heal over the twigs, causing the twig tissue to become clogged from the healing attempt. The clogs then prevent effective water and nutrient flow to the ends of the twigs, and new growth — through new needle growth — cannot continue, and the tree eventually starves.
First recorded in New York in the 1980s, scientists believe HWA likely arrived in the state on nursery stock trees sold near New York City. By 2008, HWA had been discovered in the Finger Lakes region, as well as metropolitan areas, including Syracuse, Rochester and Buffalo.
The state’s PRISMs, DEC, Hemlock Initiative and a network of hemlock and invasive species groups encourages reporting of suspected HWA sightings through iMapInvasives, a free mobile app for photographing and reporting invasive species locations. Suspected sightings can also be reported directly to your regional PRISM.
To spot HWA, the Hemlock Initiative advises people to look at the base of hemlock needles, where the needles meet the twig. At the needle base, HWA will exhibit characteristic, white woolly masses from mid-fall through spring, and in summer, HWA will appear as black sesame seeds with a thin ring of white around them.
Other signs of an infestation include: the absence of bright green foliage on the tips of hemlock branches in the spring and needle loss and dead branches in the crown.
The Oswego County detection team noted both a woolly mass and black spots on the same branch. The inactive black specimens without the woolly mass likely didn’t rise from the summer resting period, according to the team. The finding is an important reminder to check for HWA with a magnifying glass to spot the inactive nymphs in addition to woolly masses.
More information and HWA identification techniques are posted to the state Hemlock Initiative’s website. To report possible infestations, call the DEC forest pest information line at 1-866-640-0652, email SLELO PRISM Terrestrial Coordinator Robert Smith at firstname.lastname@example.org or download the iMapInvasives app.