Embark Environmental
What is Hemlock Woolly Adelgid (HWA)?
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Invasive insect that feeds on hemlock trees​​
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Insect within the Order Hemiptera (Tree Bugs), having sap sucking mouth parts​​​
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Reproduce Asexually, with one insect producing 100 eggs per gestation
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Spreads Rapidly by wildlife (Birds/Squirrels), Wind, and Human Activity (Hiking/Auto mobiles)​​
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Hemlock Woolly Adelgid will lead to mortality of up to 80-100 percent of Hemlock trees
Significance of Eastern Hemlock
A Foundational Species in the Eastern United States
One single Species supporting and making up the ecosystem
Provides Water Regulation
Filters runoff and intercepts heavy precipitation
Prevents Algae Blooms
Helps with nutrient load reduction and stabilizes tributaries and shorelines against erosion
Protects Sensitive Trout Streams
Provides cold water habitats for native trout and sensitive aquatic invertebrates
What to Look For
November - June :
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White dots/ Waxy Clumps on twig
Observe underside of twig
July - October :
Little black specks
On Twigs
Underside of Needle
Use Magnification tool - Or have Us Scout today
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Recent Spread
HWA is spreading to a majority of Counties Within New York State
Reported Observations of HWA over New York State through Imap invasives
Image: Imapinvasive
Source: imapinvasives.natureserve.org
Past Devastation
High mortality rates for untreated hemlock forest found in Virginia, New Jersey North Carolina, Tennessee, Georgia, and Connecticut
Spread of HWA since 1951 to 2021. Green area is uninfected Hemlock Forest that is at risk of Spread of HWA
Image: USDA Forest Service
Source: www.fs.usda.gov
Common Concerns
Sources
Hemlock Woolly Adelgid - NY iMapInvasives. n.d. NY iMapInvasives. Available online at https://www.nyimapinvasives.org/hwa. Accessed December 20, 2024.
Region 8 - Insects & Diseases. n.d. Available online at https://www.fs.usda.gov/detail/r8/forest-grasslandhealth/insects-diseases/?cid=stelprd3842820. Accessed January 14, 2025.