Hemlock Woolly Adelgid Training

Background History of HWA

• Hemlock woolly adelgid (HWA) (Adelges tsugae) is a non-native insect pest that kills native eastern hemlock (Tsuga canadensis)

• HWA was first discovered in Virginia in 1951 and as of 2012 has spread to 18 eastern states where it has significantly altered or reduced native hemlock populations

Background History of HWA in Tennessee

• In Tennessee HWA was discovered in Sevier & Blount counties in 2002 and has since spread west to the Cumberland Plateau and Mountains

• Much of the hemlock population in the Blue Ridge eco-region of our state has already been lost or is severely threatened by this pest

• Since 2002, HWA has spread to 36 Tennessee counties

2011 HWA Infested County & Hemlock Native Range Map

2013 HWA Infested County Map

HWA Threats• HWA is the single greatest threat to hemlock health and

sustainability in the eastern US and is comparable to Dutch Elm Disease and American Chestnut Blight in potential impacts

• If left untreated, HWA can kill a hemlock tree within 3 to 7 years of infestation

• Hemlock forests play a vital role in riparian areas as they prevent erosion on steep banks and provide shelter for wildlife by moderating temperatures in cold winter months and during hot summers days. HWA can potentially destroy these values and forever change the forest landscape

Why Hemlocks are Important to Tennessee

• Aesthetic Value• Economic Value

• Environmental Value• Personal Value

How to Identify HWA

Eggs HatchingCrawlers

Adults on Hemlock Twig

Life Cycle of HWA

Hemlock woolly adelgid annual life cycle on hemlock in North America. (From Cheah et al. 2004)

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Most Visible Sign of HWA

HWA Spread Methods• Wind• Birds and animals• Transplant of trees from infested areas• Purchasing infested nursery stock• People

Stages of Hemlock Decline

Healthy Slight defoliation

Mortality

3 7

Years

How Does HWA Kill Trees?

• Nymphs and adults insert a stylet near the base of needles and feed on sap and nutrients

• May inject a saliva into the tree to disrupt plant growth

• Because there are no natural predators, they multiply rapidly

• Sheer numbers feeding on a hemlock results in loss of vigor and eventual death (3 to 7 years)

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Methods Available to Treat HWA

• Soil Drench• Soil Injection• Stem Injection• Foliage Spray or Basal Spray

Soil Drench Method Kioritz Soil Injector

Soil Drenching

Pros:• Very easy to use• Versatile system• Lightweight • Can use both HWA

chemical products for this system

Cons:• Should not be used by

trees next to a water source

• Have to move back leaf and duff litter to expose roots to drench or create holes around base of trees

• More room for chemical amount error

• Should not be used on steep slopes

Soil InjectionPros:

• Can be used by trees next to a water source

• Can give an accurate amount of chemical to a tree

• Can use both HWA chemical products for this system

• Versatile system

Cons:

• Sometimes injector clogs up and must be cleaned

• Injector equipment is more expensive to buy than soil drench

• Hard to find Kioritz Soil Injectors are no longer being produced but other soil injectors are becoming available

• The injector needs maintenance

NU-ARBOR 1-Two Root Injector

Kioritz Soil Injector

Stem Injection

Pros:• Can be used by trees next to

a water source• Can give a accurate amount

of chemical to a tree• Less weight compared to a

soil injection

Cons:• Limited on the types of

chemicals that can be used• Equipment costs more than

other HWA treatment methods• Must drill holes in trees to

apply chemical but newer systems are becoming less invasive

• More time-consuming system compared to the other methods

• The injection system needs maintenance

• Creates wounds in the tree

Arbor-Jet Stem Injector

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Bark Spray

Pros:• Good for treating

moderate to heavy infestations

• No drilling holes in trees to apply chemical

Cons:• Cost for the chemical Safari is

more compared to Imidacloprid

• One batch per tree • Potential for drift • More potential for chemical

exposure• Can only use Safari product in

this system• Do not apply to wet bark,

during rainfall or if rain is expected within 12 hours.

D.B. Smith Contractor Series Sprayer

Foliage Spray

Pros:• Good for treating foliage

on small hemlocks• Good for treating light

to moderate infestations

• Can use both HWA chemical products in this system

Cons:• Should not be used by trees

next to a water source • The system is heavier

compared to the other HWA treatment methods

• More potential for chemical exposure

• Foliar applications are best made in late spring or from July through September when the insect is not covered by protective wool

Field King™ Backpack Sprayer

Biological Controls: Predator BeetlesPros:

• Best chance for long-term control of HWA

• Can be used on large inaccessible areas

• Good for treating moderate to heavy HWA infestations

• Three different species of beetles are being raised at UT

Cons:• Expensive: beetles can cost

between $2-$3 each & most areas require thousands of beetles for introduction

• Only nearby rearing facility is the University of Tennessee and for public lands only

• At this time, only one company in Pennsylvania is selling beetles for private landowners

• Not good for treating light HWA infestation

• Better used on smaller diameter hemlocks

Predator beetle preying upon HWA

Photo by UT Dept. Ent. and Plant Path.

Treating Light Infestation

• Full foliage, good green color in needles

• Products-Imidacloprid, • Methods-Soil injection, soil

drench, stem injection and foliage spray

• Best time to treat-Spring and Fall but can be done year-round depending on weather and soil conditions

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Treating Moderate Infestation• Thinning foliage, poorer

color, needles starting to drop

• Products-Imidacloprid, and Safari

• Methods-Soil injection, soil drench or stem injection(imidacloprid only), foliage and bark spray(Safari)

• Best time to treat-Spring and Fall but can be done year-round, depending on weather and soil condition

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Treating Heavy Infestation

• Foliage very thin or missing in places, gray green, die back is staring or occurring

• Products-Imidacloprid, Safari

• Methods-Soil injection, soil drench, stem injection(Imidacloprid) and bark spray (Safari)

• Best time to treat-Spring and Fall but can be done year-round, depending on weather and soil condition

Equipment Cost of Each Method

Soil Drench• Between $7.95-$8.18• (One 5 gallon jug or one 48 ounce

Nalgene)

Stem Injection• Between $394-$400(Hypo-Hatchet® Tree Injector or Arbor-Jet Quick Jet) Other systems cost up to $1,500 or more

Soil Injector• Between $495-$1,700(NU-ARBOR 1-Two Root Injector or HTI Soil

Injector)

Foliage/Bark Spray• Between $38.75-$67.95(D.B. Smith Contractor Series Sprayer or 4-Gallon Capacity Field King™ Backpack Sprayer)

*Please note prices will vary with sales tax, shipping cost local availability and any extra accessories you may need to buy

Chemical InformationImidacloprid:• Used in any treatment method

except bark spray• For light to moderate

infestation• Treatment life is between 3-5

years, depending on tree • Could affect honey bees and

aquatic invertebrates • Must be kept out of direct

sunlight• Can not be used in bark spray

Safari (dinotefuran):• Used in any treatment method except

stem injection• For moderate to heavy infestations• Do not apply directly to water, or to areas

where surface water is present or to areas below the mean high water mark

• For trees in forests that are pollinated by bees or other invertebrates, make applications post-bloom

• Treatment life is between 1-3 years, depending on tree

• Could affect shrimp and aquatic invertebrates

*Please be sure to read and follow all label instructions when using any pesticides.

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Cost Comparison of Chemicals

Commonly Available Sizes

Cost Range Per Unit (commonly sold sizes; not

including shipping and

handling)

Inches of Tree Diameter Treated Per

Unit

Cost Range Per Inch of Tree Diameter (not factoring for

double dosing trees ≥ 24 inches in

diameter)

Generic Brands of 75% Water Soluble Imidacloprid (75%

WSP/WSB)

pouch of 4 1.6-oz water-soluble bags

(generally the smallest available amount); flats or

barrels of 16, 48 or 88 1.6-oz water

soluble bags

$35-$50/pouch of four 192 inches/pouch of 4

$0.18-$0.26/inch of diameter (when

purchasing pouches of 4)

Generic Brands of 21.4-22.6% Flowable Imidacloprid (2F/2L) 1 gallon $120-$180/gallon 1,093 inches/gallon $0.11-$0.16/inch of

diameter

Imidacloprid Tablets(Cortect brand only) 250-tablet bottle $120-$180/bottle

of 250125 inches/bottle of

250$0.96-$0.1.44/inch

of diameter

Imidacloprid 5% Injectable Chemical (Ima-Jet brand only)

1 Liter; case of 4 Liters $250-$300/Liter 250 inches/Liter $1.00-$1.20/inch of

diameter

Dinotefuran 20SG Soluable Granule (Safari brand only)

3 pound bottle; 12-ounce bottle

$370-$390/3 pounds 468 inches/3 pounds $0.80-$0.85/inch of

diameter

Cost Comparison of Chemicals

Inches of Tree Diameter Treated Per Unit

Low Price 10in/26in tree

High Price 10in/26in tree

Generic Brands of 75% Water Soluble Imidacloprid (75% WSP/WSB)

192 inches/pouch of 4 $1.80-$9.36 $2.60-$13.52

Generic Brands of 21.4-22.6% Flowable Imidacloprid (2F/2L) 1,093 inches/gallon $1.10-$5.72 $1.60-$8.32

Imidacloprid Tablets (Cortect brand only) 125 inches/bottle of 250 $9.60-$49.92 $14.40-$74.88

Imidacloprid 5% Injectable Chemical (Ima-Jet brand only) 250 inches/Liter $10.00-$52.00 $12.22-$63.44

Dinotefuran 20SG Soluble Granule (Safari brand only) 468 inches/3 pounds $8.00-$41.60 $8.50-$45.76

*Tree greater than 24 inches have to be double dose

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Steps for Private Landowners Treating HWA

Determine your goals and objectives for your forest as well as for your hemlocks. Treating your hemlocks should be a long term commitment that may involve multiple treatments. Developing a comprehensive forestry management plan is highly encouraged

1. Inspect trees to determine level of HWA infestation present: none, light, moderate or heavy.

2. Assess site conditions

3. Overall tactic

4. Collect tree data

5. Types of treatment and options for labor

6. Types of chemical for treatment

7. Chemical treatment methods

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Steps for Private Landowners Treating HWA

8. Mixing rates

9. Estimate cost of treatment

10. Combine Tree Data and the Cost of Chemical

*NOTE: It is the user's responsibility to read and follow all label instructions when using any pesticide materials.

For more information or technical assistance for landowners, please

contact:Douglas Godbee

865.318.1371Douglas.Godbee@tn.gov

or visit

www.protecttnforests.org