A minor infestation of the Hemlock Woolly Adelgid (Adelges tsugae)
was confirmed on Forest Preserve lands in the town of Lake George in
Warren County on July 18, the New York State Department of Environmental
Conservation (DEC) announced. This is the first known infestation
of Hemlock Woolly Adelgid (HWA) in the Adirondacks.
"To track and prevent the spread of this invasive pest, Hemlock
Woolly Adelgid, DEC has surveyed 250 acres of forest in the
Adirondacks," said DEC Commissioner Seggos. "Preventing the spread of
invasive species is the most effective way to fight and address the
damage these species can cause to our natural resources. DEC encourages
hikers, campers, boaters, sportsmen, and others recreating on or along
forestlands in northern Schenectady, Saratoga, and southern Warren
counties to check Eastern Hemlock trees and report any HWA
infestations."
A small cluster of early stage HWA was detected on one branch of an
old-growth Eastern hemlock tree on Prospect Mountain during a field trip
by a Senior Ecologist from the Harvard Research Forest.
NYDEC immediately dispatched a survey crew to the site and was
joined by staff from Cornell University's New York State Hemlock
Initiative. HWA was located and confirmed on a number of branches on the
tree by a Cornell scientist and later by DEC's DEC Diagnostic Lab. The
mature tree had no visible sign of crown thinning.
The crews surveyed 250 acres of forest and
found only one other tree, a small Eastern hemlock near the original
infested tree, that contained one branch with a small cluster of early
stage HWA.
This is the first recorded infestation of this invasive, exotic pest
in the Adirondacks. Previously, it has been detected in 29 other
counties in New York, primarily in the lower Hudson Valley and, more
recently, in the Finger Lakes region. Seventeen other states along the
Appalachian Mountain range from Maine to Georgia also have HWA
infestations. HWA is a listed prohibited species under DEC's invasive
species regulations.
DEC is evaluating means to eradicate this infestation and prevent it
from spreading. This will not include cutting down trees, which is not
an effective means for controlling HWA as it is with other invasive
forest pests.
The most effective treatment method for control of HWA is the use of
insecticides. The insecticide is applied to the bark near the base of
the hemlock tree and are absorbed and spread through the tissue of the
tree. When HWA attaches itself to tree to feed, it receives a dose of
the pesticide and is killed.
In the past three years DEC has treated infested hemlock trees with
insecticides at a few select locations where the control is likely to
slow the spread of HWA, or where the hemlocks provide a significant
public value. New York State Office of Parks, Recreation, and Historic
Preservation has treated many hemlocks trees at a number of State Parks.
Both chemical and biological control options are important in the
long-term fight against HWA.
Dispersal and movement of HWA occur primarily during the first life
stage ("crawler") as a result of wind and animals that come in contact
with the sticky egg sacks and crawlers. Isolated infestations and
long-distance movement of HWA, most often occur as the result of people
transporting infested nursery stock.
DEC monitors the distribution and spread of HWA by annual aerial and
ground surveys as well as reports from partners and the general public.
DEC has been involved in biological control efforts against HWA since
the 1990s, and has released several approved natural enemies of HWA at
locations in the Finger Lakes and Catskills regions.
HWA, a tiny insect from East Asia first discovered in New York in
1985, attacks forest and ornamental hemlock trees. It feeds on young
twigs, causing needles to dry out and drop prematurely and causing
branch dieback. Hemlock decline and mortality typically occur within
four to 10 years of infestation in the insect's northern range.
Damage from the insect has led to widespread hemlock mortality
throughout the Appalachian Mountains and the southern Catskill Mountains
with considerable ecological damage, as well as economic and aesthetic
losses. HWA infestations can be most noticeably detected by the small,
white, woolly masses produced by the insects that are attached to the
underside of the twig, near the base of the needles.
Eastern hemlock trees, which comprise approximately 10 percent of the
Adirondack forest, are among the oldest trees in New York with some
reaching ages of more than 700 years. They typically occupy steep,
shaded, north-facing slopes and stream banks where few other trees are
successful. The trees help maintain erosion control and water quality,
and the hemlock's shade cool waters providing critical habitat for many
of New York's freshwater fish, including native brook trout.
Survey efforts by DEC and Cornell's New York State Hemlock Initiative
will continue to determine if other infestations are present in the
surrounding area. As the closest known infestation of HWA is 40 miles
away in Schenectady County, DEC is asking hikers, campers, boaters,
sportsmen, and others recreating on or along forestlands in northern
Schenectady, Saratoga, and southern Warren counties to check Eastern
Hemlock trees and report any HWA infestations.
New York is particularly vulnerable to invasive species due to its
rich biodiversity and role as a center for international trade and
travel. Rapid response and control is a critical line of defense in
minimalizing the establishment, and ultimately permanently removing, an
invasive population.
More information on
HWA, including identification, control techniques, and reporting possible infestations can be found at
Cornell's New York State Hemlock Initiative (link leaves DEC's website) or DEC's website. You can also call DEC's toll-free Forest Pest Information Line at
1-866-640-0652 to ask questions and report possible infestations.
