Why Hemlocks are Important
Scenic Beauty1
Erosion Control2
Hydrology Modification
Cooling Temperatures -Trout Habitat
Internal Ecosystem -Rare Species Habitat
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3
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2
Hemlock Dependant Species
Canadian Museum of Nature
Threats to Hemlock Trees
Drought
Development
Spider-Mites ………
Scales …………………
Mark S. McClure
HWA …………………..
Hemlock Woolly Adelgid
Invasive.org
The Hemlock Woolly Adelgid
(Adelges tsugae)
A True Bug, native to East Asia that feeds by sucking sap
from hemlock trees (new growth, inject toxin)
HWA is introduced to N. America in 1924 (PA: 1967)
No native predators = major threat to the Eastern hemlock
(Tsuga canadensis) & Carolina hemlock (Tsuga caroliniana)
The pest has now been established from GA to MA, causing
widespread mortality of hemlock trees.
50% of the geographic range of eastern hemlock has been
impacted by HWA.
Infestation Distribution
Symptoms of HWA Impact
How do you know HWA is impacting your Hemlock Trees?
Presence of white, cottony egg sacs clinging to the underside
of hemlock branches
Gradual fading and browning of limbs
Graying, dry or brittle needles which begin dropping
Trees with skeletal, spider web-like appearance and
defoliated understory
Presence of one or more other pests/diseases
The Hemlock Woolly Adelgid
HWA Life Cycle
6
1
5
R. Childs
2
4
3
3
7
2
1
5
Invasive.org
www.invasive.org
6
7
R. Childs
4
The Hemlock Woolly Adelgid
If HWA is left uncontrolled, ultimate result is the Loss of
Hemlock Trees. (4-6 yrs)
Death of Hemlocks would result in:
(impact photos)
Erosion 
Change in Ecosystem
Fire Hazard
Aesthetic Loss
Safety
Lyme disease
Economics of removal
The Hemlock Woolly Adelgid
If HWA is left uncontrolled, ultimate result is the Loss of
Hemlock Trees. (4-6 yrs)
Death of Hemlocks would result in:
(impact photos)
Erosion
Change in Ecosystem
Fire Hazard
Aesthetic Loss
Safety
Lyme disease
Economics of removal
Will Blozan
The Hemlock Woolly Adelgid
Monitoring HWA
Develop an Understanding (How it travels)
Natural Controls
(cold/predation)
Early detection
Frequent inspection
The Hemlock Woolly Adelgid
Create an inventory
Locate, map, & evaluate most imp. Trees
*monitor recovery, type of treatment, safety of bio control*
Value matrix
HWA Control Methods
Cultural
Reducing invasion
Improving tree health
Mechanically removing HWA
Planting resistant hemlock species
Chemical
Horticultural Oils/ Soaps
Pesticides (General info.)
Methods of Application (Spray, Root, or Stem inj.)
Evaluating Effectivenes
Biological Control
ST Beetle: Sasajiscymnus tsugae
Only Long term solution
Availability
HWA Cultural Control
Cultural Control
Reducing invasion
Improving tree health
Mechanically removing HWA
Planting resistant Hemlock
species
clevelandpublicart.org
HWA Chemical Control
Chemical Control
Horticultural Oils/ Soaps
Pesticides
Methods of Application
(Spray, Root, or Stem inj.)
Evaluating Effectiveness
Trees-america.com
HWA Biological Control
Biological Control
Only Long term solution
ST Beetle: Sasajiscymnus tsugae
Where it comes from
Why it is successful
Predatory practices
Comparative Life-cycle
Winter Hardy
Years of Observation
From Lab to Release
Availability/ Supply & Demand
Most wanted by private consumers due to price, success
stories, HWA only main food source and most compatible
with other releases. Most people invested in ST beetles so
they can interbreed with neighbors.
ST Beetle Life Cycle
Egg
Larvae
Pupa
Adult
Options
No management
Removal & replacement of dead trees
Treat, prevent and control infestation
Biological Control
Combination Approach
Questions & Comments
Works Cited
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"Biological Control of Hemlock Woolly Adelgid @ Invasive.org." Invasive Species: Information, Images, Videos, Distribution Maps.
18 Apr. 2009 <http://www.invasive.org/hwa/>.
"Blackside Dace |." Pajamadeen.com. 18 Apr. 2009 <http://www.pajamadeen.com/tag/blackside-dace>.
Bonta, Dave. Porcupine in hemlock. 24 Sept. 2006. Dave Bonta's photostream, Www.flickr.com.
Cleveland Public Art. 18 Apr. 2009 <http://www.clevelandpublicart.org/files/projects/images/800/eco-fence-bird-house.jpg>.
"Climb of the Caldwell Colossus." Eastern Native Tree Society. 18 Apr. 2009
<http://www.nativetreesociety.org/tsuga/caldwell_colossus/caldwell_colossus.htm>.
Consumer Information about Tree Service from TreeCareTips.org. 18 Apr. 2009
<http://www.treecaretips.org/images//Hemlock3.jpg>.
Eastern Native Tree Society. 18 Apr. 2009 <http://www.nativetreesociety.org/tsuga/finale/Colleague_Little_Spruce_Ridge_covered_in_dead_hemlocks-_note_lack_of_hardwoods.JPG>.
"Hemlock Woody Adelgid -." Landscape Nursery and Urban Forestry - UMass Extension. 18 Apr. 2009
<http://www.umassgreeninfo.org/fact_sheets/piercing_sucking/hemlock_woolly_adelgid.html>.
"Hemlock woolly adelgid -." Wikipedia, the free encyclopedia. 18 Apr. 2009
<http://en.wikipedia.org/wiki/Hemlock_Woolly_Adelgid>.
"Hemlock Woolly Adelgid Update." Chattooga Conservancy. 18 Apr. 2009
<http://www.chattoogariver.org/index.php?quart=Su2002&req=hwaupdate>.
HGIC - Plant Diagnostic Web Site. 18 Apr. 2009 <http://plantdiagnostics.umd.edu/level3.cfm?causeID=859>.
"HWA." Rutgers: CRSSA. 18 Apr. 2009 <http://crssa.rutgers.edu/courses/lse/Web_scale/Web%20project/HWA.htm>.
"Invasive Species: Animals - Hemlock Woolly Adelgid (Adelges tsugae)." National Invasive Species Information Center. 18 Apr.
2009 <http://www.invasivespeciesinfo.gov/animals/hwa.shtml>.
Invasive Species: Information, Images, Videos, Distribution Maps. 18 Apr. 2009
<http://www.invasive.org/hwa/images/Figure3.gif>.
"Moss Spraying." Trees America Welcome Page. 18 Apr. 2009 <http://www.trees-america.com/mossx.com/>.
Northeastern Area State & Private Forestry - USDA Forest Service. 18 Apr. 2009
<http://www.na.fs.fed.us/fhp/hwa/pdfs/mcclure_hwa.pdf>.
"Northern Flying Squirrel, Glaucomys sabrinus." Canadian Museum of Nature - Mus?canadien de la nature. 18 Apr. 2009
<http://nature.ca/notebooks/english/flysquir_p8.htm>.
"Pest Alert - Elongate Hemlock Scale." Northeastern Area State & Private Forestry - USDA Forest Service. 18 Apr. 2009
<http://www.na.fs.fed.us/spfo/pubs/pest_al/ehscale/ehscale.htm>.
"Save Our Hemlocks - Hemlock Woolly Adelgid Facts." Save Our Hemlocks Home Page. 18 Apr. 2009
<http://www.saveourhemlocks.org/adelgid.shtml>.
Thank-You