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Hemlock Woolly adelgid. Tennessee Division of Forestry. Background History of HWA. Hemlock woolly adelgid (HWA) ( Adelges tsugae) is a non-native insect pest that kills native eastern and carolina hemlocks ( Tsuga canadensis & Tsuga caroliniana )
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Hemlock Woolly adelgid Tennessee Division of Forestry
Background History of HWA • Hemlock woolly adelgid (HWA) (Adelges tsugae) is a non-native insect pest that kills native eastern and carolina hemlocks(Tsuga canadensis & Tsuga caroliniana) • 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 • 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
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
HWA Threats • Hemlock forests play a vital role in riparian areas as they: • - prevent erosion on steep banks which helps to prevent disruptive water quality issues • - provide shelter for many wildlife species • - keeps water temperatures moderate in cold winter months and cool during hot summers days for aquatic species • HWA can potentially destroy these values and forever change the forest landscape!!
Aesthetic Value Economic Value Environmental Value Personal Value Why Hemlocks are Important to Tennessee
Wind Birds and animals Transplant of trees from infested areas Purchasing infested nursery stock People HWA SpreadMethods
Stages of Hemlock Decline Healthy Slight defoliation Mortality 7 3 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 Multiply rapidly- no natural predators Sheer numbers feeding on a hemlock results in loss of vigor and eventual death (3 to 7years)
Biological Controls: Predator Beetles Laricobius nigrinus beetle being release on state forest land Pros: • 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 • Successfully introduction requires extremely specific site conditions • Only nearby rearing facility is the University of Tennessee and for public lands only • Two companies in Pennsylvania and North Carolina are selling beetles for private landowners
Chemical Information-Imidacloprid Imidacloprid: • For light to moderate infestation • Treatment life is between 3-8 years, depending on tree • Must be kept out of direct sunlight
Chemical Information-Imidacloprid • Imidacloprid is a Neonicotinoid insecticide are synthetic derivatives of nicotine, an alkaloid compound found in the leaves of many plants in addition to tobacco. • Could affect honey bees and aquatic invertebrates • Treatment Methods Use: Soil Drench, Soil Injection, Stem Injection and Foliage Spray
Chemical Information-Dinotefuran • Dinotefuran (Safari): • For moderate to heavy infestations • Do not apply within 20 feet of direct water source, 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
Chemical Information-Dinotefuran • Must be kept out of direct sunlight • Treatment life is between 1-3 years, depending on tree • Could affect shrimp and aquatic invertebrates • Treatment Methods Use: Soil Drench, Soil Injection, Foliage and Bark Spray • *Please be sure to read and follow all label instructions when using any pesticides.
Soil Drench Soil Injection Stem Injection Foliage Spray or Basal Spray Methods Available to Treat HWA Kioritz Soil Injector Soil Drench Equipment
Pros: Very easy to use Versatile system Lightweight Can use both HWA chemical products for this system Soil Drenching Cons: • Have to move back leaf and duff litter to expose roots to drench • More room for chemical amount error • Should not be used on steep slopes • Can not be used at least 5 foot from a water source for Imidacloprid and 20 feet for Dinotefuran Soil Drench Equipment
Soil Injection Pros: • Can give an accurate amount of chemical to a tree • Can use both HWA chemical products for this system • Versatile system NU-ARBOR 1-Two Root Injector Cons: • Sometimes injector clogs up and must be cleaned and needs maintenance • Hard to find KioritzSoil Injectors are no longer being produced but other soil injectors are becoming available • Can not be used at least 5 foot from a water source for Imidacloprid and 20 feet for Dinotefuran KioritzSoil 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 other treatment methods Arbor-Jet Stem Injector Cons: Can only use Imidacloprid chemical in injector Equipment costs more than other HWA treatment methods Must drill holes in trees to apply chemical but newer systems are becoming less invasive Creates wounds around the base of the tree Trees need to have greater than 50% live crown left for successful treatment
BarkSpray Pros: • Good for treating moderate to heavy infestations • No drilling holes in trees to apply chemical D.B. Smith Contractor Series Sprayer Cons: More potential for chemical exposure and drift Can only use Dinotefuran chemical in this system Do not apply to wet bark, during rainfall or if rain is expected within 12 hours. Can not be used within the 20 feet of a water source
Foliage Spray Pros: • Good for treating foliage on small hemlocks with trees less than 30 feet in height • Good for treating light-heavy infestations Field King™ Backpack Sprayer Cons: • Can not be used at least 5 foot from a water source for Imidacloprid and 20 feet for Dinotefuran • More potential for chemical exposure and drift • Best to begin applications before the onset of high pest populations • Foliar applications are best made in late spring or from July through September when the insect is not covered by protective wool
Treating Light Infestation • Full foliage, good green color in needles • Products-Imidacloprid, Dinotefuran • Methods-Soil injection, soil drench, foliage spray and stem injection • Best time to treat-Spring and Fall but can be done year-round depending on weather and soil conditions
Treating Moderate Infestation • Thinning foliage, poorer color, needles starting to drop • Products-Imidacloprid, Dinotefuran • Methods-Soil injection, soil drench, foliage, bark spray and stem injection • Best time to treat-Spring and Fall but can be done year-round, depending on weather and soil condition
Treating Heavy Infestation • Foliage very thin or missing in places, gray green, die back is starting or occurring • Products-Imidacloprid, Dinotefuran • Methods-Soil injection, soil drench, bark spray and stem injection • 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 Dench • Between $7.95-$8.18 (One 5 gallon jug or one 48 ounce Nalgene bottle) Stem Injection • Between $394-$400 (Hypo-Hatchet® Tree Injector or Arbor-Jet Quick Jet) Other systems cost up to $1,500 or more *Please note prices will vary with sales tax, shipping cost local availability and any extra accessories you may need to buy 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)
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 Inspect trees to determine level of HWA infestation present: none, light, moderate or heavy. Assess site conditions (soils, terrain, slopes and accessibility of site)
Steps for Private Landowners Treating HWA Collect tree data (record for each trees dbh and number of trees per acre for site) Based on steps 2-4, determine treatment strategy (chemical type, amount of chemical, labor and treatment method) Estimated cost of Treatment Develop long term budget for continue treatment for HWA *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 please contact: • Douglas Godbee • 865.318.1371 • Douglas.Godbee@tn.gov • or visit • www.protecttnforests.org