Key Tree and Shrub Insect Pests in the Landscape

3/14/17

Insect Pests in the Landscape Key Tree and Shrub Insect • Ornamental Insect Pests Pests in the Landscape – Sucking Insects – Japanese Beetle – Boring Insects • Two-line Chestnut Borer • Bronzed Birch Borer Dr. R. Chris Williamson • EAB Department of Entomology • Linden Borer University of Wisconsin-Madison – Gypsy Moth – Fall Webworm – Viburnum Leaf Beetle

Sucking Arthropod Pests Sucking Pests of Ornamental Plants

• Most plant pests with sucking mouthparts belong to • Plant Bugs the insect order Hemiptera (True Bugs) • Lace Bugs – This group includes: aphids, cicadas, sXnk bugs, scale insects, • Aphids and Adelgids and their kin • Leaôppers – ~80,000 species known! • Treehoppers • Spi_lebugs • Jumping Plant Lice (Psyllids) • Other plant pests with sucking mouthparts include • Scale Insects (Armored or So`) Thrips, whiteflies, mealybugs • Whiteflies and certain mites • Mealybugs • Thrips

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IdenXfying Plant Bugs Plant Bugs: Four Lined Plant Bug

• DisXnct Triangular Region • Pest on numerous annuals and present on wings perennials • Ex. azaleas, dogwood, maples, • This is disXnct to the family sumac Miridae (Plant Bugs) • Overwinter as eggs • Nymphs (red and black) emerge and feed in April/May • Adults (~1/4”; black and yellow) can be found in May/June • 1 generaXon per year

Plant Bugs: Four Lined Plant Bug Plant Bugs: Ash Plant Bug

• Pests of ash trees (what’s le`!) • Both nymphs and adults feed • Overwinter as eggs and can damage plants • Nymphs (reddish) emerge around leaf break • O`en cause dark spots on leaves (my resemble a disease); • Adults (~1/4”; black and yellow) can also cause curling of plant can be found in May through Xssues the growing season • 2 generaXons per year • May drop to ground and hide if disturbed

Photos: James Solomon USDA; Whitney Cranshaw

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Plant Bugs: Ash Plant Bug Plant Bugs: Honeylocust Plant Bug

• Both nymphs and adults feed • Pest of honeylocust trees and can damage plants • Overwinter as eggs – First generaXon for the year is most damaging, as feeding occurs on • Nymphs (yellowish-green) young leaves emerge around leajreak

• Adults (~1/4”; greenish) can be • Cause a yellow, mo_led found in June appearance on leaf surfaces – Young leaves can appear wilted • 1 generaXons per year; populaXons decline in late June/ Nymph Adult July

Photos: Jeﬀ Hahn, UMN Entomology Dept.; James Solomon USDA

Plant Bugs: Honeylocust Plant Bug Lace Bugs • Several species in the Midwest • Cause mo_ling and distorXon of leaves; young leaves may be • Numerous hosts: azaleas, oak, elm, curled (can resemble herbicide damage) birch, crabapple, linden, aspens, • Prefer yellow varieXes of honeylocust (‘Sunburst’) over green willows, roses, and others varieXes (‘Shademaster’ or ‘Skyline’) • White or black colored; wings pa_erned with ornate, lace-like pa_ern; adults ~1/8-1/4”

• Typically overwinter as adults (and some eggs); mulXple generaXons per year; can be found into the fall

Immatures Adults

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Lace Bugs Lea^oppers • Can cause yellowing (chlorosis) • Wide variety of plants are or sXppling of leaf Xssue a_acked by lea^oppers – Damage can appear similar to • Can cause stunted growth; that of spider mites browning, and curling of leaves (“Hopper Burn”) • Lace bugs found on underside of leaves • Can carry and transmit plant diseases

• Plant damage can be sever if diseases have been transmi_ed!

Hopper Burn on Apple

Treehoppers Management of Sucking Insects (excluding scale insects) • IdenXfiable by crest on top of head • Wide variety of insecXcides available to manage Sucking pests • RelaXvely minor pests of ornamentals • Check the label to make sure a product meets usage requirements Insects Type of Insec8cide Examples of Ac8ve Ingredients • Damage to foliage is usually superficial/cosmeXc Organophosphates Acephate, chlorpyrifos* • Can damage while laying eggs (oviposiXon scars) Plant Bugs Lace Bugs Chinch Bug Carbamates Carbaryl Aphids Adelgids Pyrethroids Bifenthrin, cyfluthrin, fluvalinate, Leaôppers deltamethrin, permethrin, pyrethrin Treehoppers Spi_lebugs NeonicoXnoids Clothianidin, dinotefuran, imidacloprid, Psyllids thiamethoxam Whiteflies Mealybugs Other InsecXcidal soaps, horXcultural oils, OviposiXon Scars Buffalo Treehopper Thrips azadirachXn

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Management of Sucking Insects (excluding scale insects) Scale Insect Pests

• Some of the aforemenXoned insect pests cause • Two Types: Armored (i.e., Hard) and So` Scales superﬁcial/cosmeXc damage • > 60 species in Midwest (see Dr. Cliﬀ Sadof’s website) • May be able to avoid pesXcide use • Damage plant by sucking plant juices • Ex. If few galls are present, prune (remove) them • RelaXvely immobile, only move as crawlers in summer

Armored vs. So` Scales Scale Feeding Pa_erns: Leaf Cross SecXon:

Armored Scales So@ Scales Protec8on Hard/Armored protecXve No true armor, protected coaXng; can be removed by waxy secreXon; protecXon can NOT be removed Length of Mouthparts Long piercing mouthpart Short piercing mouthpart Feeding Loca8on Mesophyll feeders Phloem feeders Forma8on of honeydew No honeydew formaXon Excrete honeydew Overwintering Stage Usually eggs Usually nymphs Soft Reproduc8ve Capacity Females produce ~100 Females produce ~1,000 eggs (less dynamic) eggs (more dynamic)

Armored

Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates

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Scales encrust branches and/or leaves; cause Armored Scale Insects dieback and death of plant

Armored Scales Form a “Shell-like” Cover from Shed Skins and Waxy SecreXons Covers ﬂipped (removed) to reveal scale insects

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Common Armored Scale Insects

• Obscure Scale • Oystershell Scale • Pine Needle Scale • Euonymus Scale • Juniper Scale Close-up of Armored Scale Insect

Obscure Scale

• Major pest of pin oaks • Encrusts limbs, branches • Causes stress, die-back, tree decline, and even tree death

Thinning, Dieback from Obscure Scale

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Oystershell Scale Pine Needle Scale A_acks lilac, maple, willow, ash, poplar, apple, hawthorn, dogwood, others

Euonymus Scales: Males (White) and Euonymus Scale Females (Gray)

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Males Mostly Infest Leaves

Chlorosis due to feeding Dieback from Euonymus Scale

Japanese Beetle Biology

• Adults emerge in mid-June through early- September • Adults are gregarious, sun-loving animals • Adults are skeletonizers, NOT defoliators • Adults feed on leaves, flowers and fruit • Attack >350 species • ONE year life cycle

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Japanese Beetle Life Stages –

egg 1st 2nd 3rd pupa adult instar larva

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Management Systemic InsecXcides

• Systemic Insecticides: Soil drench or injection • Acetamaprid (Tristar) • Trans-laminar products applied to foliage prior to • Clothianidin (Arena) or during adult activity (after flowering!) • Dinotefuran (Safari) • Contact insecticides applied directly to active adults (under sunny conditions in upper canopy, • Imidacloprid (Merit)* after flowering)- Avoid applications to flowering • Thiamethoxam (Meridian) plants! • Acephate (Lepitect)-Orthene – Imidacloprid can not be applied to basswood or linden species! – Imidacloprid can not be applied to basswood or linden species!

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Trans-laminar InsecXcides Contact InsecXcides

• Acetamaprid (Tristar) • SyntheXc Pyrethroids • Clothianidin (Arena) – Bifenthrin (Talstar) • Dinotefuran (Safari) – Beta-cyﬂuthrin (Tempo) – • Imidacloprid (Merit)* Deltamethrin (Deltaguard) – Lambda-cyhalothrin (Scimitar) • Thiamethoxam (Meridian) • Carbaryl (Sevin) – Imidacloprid can not be applied to basswood or linden species! • Chlorantraniliprole (Acelepryn) • Permethrin (Astro)

Two-lined Chestnut Borer Two-Lined Chestnut Borer

• Native species • Coleoptera: Family Buprestidae • Adult = Metallic Wood Borer • Larva = Flat Headed Borer • Hosts – Oak and Chestnut, stressed trees are most susceptible • Life Cycle = ONE year, sometimes two years in northern climates and poor trees

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DAMAGE

• Injury symptoms caused by girdling first appears as limb dieback and thinning of crown, similarly to Bronze birch borer • Adults create D-shaped exit holes

BIOLOGY MANAGEMENT

• Adults emerge in June – mid-Sept. • Systemic insecticide applications preceding fall are effective as preventative treatments, NOT • Adults are sun-loving curative! • Eggs are laid in crack and crevices in the – Imidacloprid (Merit) trunk bark, usually in sections exposed to – Chlothianidin (Arena) – Thiamethoxam (Meridian) sunlight • Bark spray applications made once adult Two- • Larvae primarily tunnel in cambium layer lined Chestnut Borer adults are active (i.e., late- under bark May –June) – Permethrin (Astro) • ONE generation per year, sometimes – Bifenthrin (Onyx) requires two years in northern climates! – Chlorpyrifos (nursery ONLY)

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Bronze Birch Borer Bronzed Birch Borer

• Native species • Coleoptera: Family Buprestidae • Adult = Metallic Wood Borer • Larva = Flat Headed Borer • Hosts – European white birch, especially stressed trees • Life Cycle = ONE year, sometimes two year in northern climates

DAMAGE

• Initial damage symptoms appear as crown dieback • Larvae feed mainly in cambial area creating callused girdling that spirals around the bark • Adults create D-shaped exit holes

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BIOLOGY

• Adults emerge in late-May – June • Adults lay most eggs in the upper crown on branches < 1 inch diameter • Stressed trees are more susceptible • Larvae tunnel in cambium layer under bark, rarely moving into xylem • ONE generation per year, sometimes requires two years in northern climates!

MANAGEMENT

• Systemic insecticide applications preceding fall are effective as preventative treatments, NOT curative! – Imidacloprid (Merit) – Thiamethoxam (Flagship, nursery ONLY) • Bark spray applications made once adult Bronze birch borer adults are active (i.e., late-May – June) – Permethrin (Astro) – Bifenthrin (Onyx) – Chlorpyrifos (nursery ONLY)

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History of EAB

• ExoXc, Invasive Insect (NaXve to Asia) • 1st Discovered in the US near Detroit, MI (2002) • Arrived on Solid Wood Packing Material about 10 years previously • 1st Discovered in Wisconsin in August 2008 (Newburg, WI), infestaXon likely occurred in early 2000 • Primarily Spread by Infested Ash Products (i.e., Firewood)

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EAB Biology

• BupresXd, Metallic Wood Borer • Agrilus spp., closely related to Bronzed Birch Borer and Two-lined Chestnut Borer • Gregarious, Sun-loving Animal • Trees in Open Sevngs are Most Vulnerable to A_ack • Adults are Good Fliers Compared to Other Beetles • A_ack Predominantly Ash (Fraxinus spp) – Stressed or Healthy – Tree size has NO Inﬂuence (1/2 - > 50 inch DBH)

EAB Life Cycle Closely Related Agrilus spp June – September June – October

Late May – August November – Late May A. anxius A. bilineatus

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A_ack in Open Sevng is Most Common

Typical Edge A_ack

EAB a_acks ash trees of EAB Adult all sizes (1/2” - > 50”)! • Emerald, metallic green • D-shaped body • 3/8-1/2 in long

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EAB Larvae Damage Caused by EAB • Legless larva • Larvae feed in the cambial area (xylem and phloem), thus

destroys the conducXve Xssues • ~ 1½ in long • Damage typically originates in upper canopy • 10 segmented body, • Ash tree exhibit signs/symptoms cream-colored, with of an EAB infestaXon by upper distinct “bell-shaped” crown dieback abdominal segments

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Achilles Heal of EAB

• NO effecXve or efficient early detecXon tool or strategy • Damage symptoms oèn occur (canopy dieback) aèr measurable damage results and infestaXon level is high

Host Plants Are Insecticides Effective? • Attacks Ash (Fraxinus spp.) – Green ash (F. pennslyvanica) – White ash (F. americana) • Eradication = NO! – Blue ash (F. quadrangulata) • Tree Protection = YES! – Black ash (F. nigra) – Primarily for high-value, specimen, heritage or – European ash (F. excelsior) legacy ash trees – NOT for EAB infested ash trees with > 40-50% • Mountain ash (Sorbus spp.) is canopy thinning/dieback NOT attacked! – NOT likely cost effective for woodlots or forested areas* (borerGONE?)

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Common MisconcepXons Regarding Facts About EAB InsecXcide Treatments • Ash trees will NOT survive if they aren’t treated with Management of EAB an insecXcide (InsecXcides are effecXve!) • Treeäge is NOT the only effecXve insecXcide • Ash Trees can NOT be Protected or Saved • Five acXve ingredients (ai) are available – Imidaclorprid (Merit, Xytect and others) • InsecXcide Treatments are NOT EffecXve – Dinotefuran (Safari) • InsecXcide Treatments are Cost ProhibiXve – EmamecXn Benzoate (Treeäge + ArborMecXn) – AzacdirachXn (TreeAzin) • Only ONE insecXcide treatment is effecXve – Clothianidin (Bayer Advanced) • Pre-empXve Removal of Healthy Ash Trees • Several applicaXon technologies exist – Soil drench or injecXon Slows the Spread of EAB – Trunk InjecXon (ArborJet, Rainbow, Wedgle, Mauget, others) – Basal Bark Spray – Aerial (canopy) sprays for adults

Professional EAB InsecXcide Treatment OpXons • AzadirachXn What about TreeAzin? • TreeAzin (Trunk InjecXon, BioForest Technologies) • Bacillus thuringiensis – boreGONE (AdulXcide, Phyllom BioProducts)*NOT Registered! • TreeAzin (azadirachXn) is a systemic • Dinoterfuan insecXcide produced from extracts of Neem – Safari (Basal Bark Spray and Soil Drench/InjecXon, NuFarm) – Transtect (Basal Bark Spray or Soil Drench/InjecXon, Ranibow ScienXﬁc) tree seeds – Dinocide (microinjecXon, Mauget) • EmamecXn Benzoate • TreeAzin is an insect growth regulator (IGR ) – Boxer (Trunk InjecXon, ArborSystems), Non-RUP – ArborMecXn (Trunk InjecXon, Rotam), Non-RUP that disrupts molXng (development) – Treeäge G4 (Trunk InjecXon, Arborjet), Non-RUP – Treeäge (Trunk InjecXon, Arborjet), RUP* • Thus, only larvae are aﬀected • Imidacloprid – Merit (soil drench or injecXon); numerous other brands – Xytect (soil drench or injecXon) – Pointer (Trunk InjecXon, ArborSystems) – IMA-Jet (Trunk InjecXon, Arborjet) – Imicide (Trunk InjecXon, Mauget)

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Dr. Deb McCullough Research 18” or smaller ash trees • TreeAzin does not kill adults, but reduces fecundity and egg hatch rates • However, EAB adults recovered a`er feeding on untreated foliage a`er a week • TreeAzin kills young (small) EAB larvae for up to 2 years when EAB populaXons are relaXvely low

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Homeowner EAB InsecXcide Treatment OpXons OpXmal Timing of EAB Treatments

1) Bayer Advanced Tree and Shrub Insect Control • Soil Treatments: In Spring allowing Xme for 2) Ferti-loam Systemic Tree and Shrub Drench uptake before adults begin to feeding and 3) Gordon’s Tree and Shrub Insect Killer eggs begin to hatch 4) The Max Tree and Shrub Insect Killer 5) Optrol (same 2X rate as Xytect) • Trunk InjecXons: In Spring just a`er the canopy has fully developed Other products may exist, market changes regularly!

EAB Adult Emergence Begins when EAB Adults are acXve between 450 - Black Locust Blooms (≈ 500 GDD) 500 GDD

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Key Conclusions Key Conclusions • InsecXcides are eﬀecXve • NeoniciXnoid treatments must be – Including large trees even under applied annually (ideally in spring) intense pest (EAB) pressure • Spring treatment performs be_er • Safari soil and basal bark spray than fall applicaXons treatments provide good control • Treeäge provides 2 years of control when applied at appropriate Xming at low label rate and potenXally up (May – early June, Do NOT apply to 3 years at higher label rates too late!)

What About the Cold? Linden Borer

• EAB larvae begin to die around -22 °F (-30 °C) or colder • As temperatures approach -30 °F (-34 °C), ~90% of EAB larvae die

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Female Male

DAMAGE DAMAGE

• Larvae feed mainly in cambial area in • Stressed trees appear to be most smaller trees and in the xylem in larger vulnerable to attack trees • Small trees (< 4 inch DBH) in nurseries • Larvae overwinter and pupate in tunnels are also susceptible, especially at graft under bark union • Adults create round exit holes • Most damage is at base up to first lateral approximately 3/8 inch diameter branch

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Biology • Adults are active from June – September Management

Number of adult linden borer captured • Bark spray treatments MUST be made in 2003 and 2004. prior to adult activity

120 – Permethrin (Astro) 100 – Bifenthrin (Onyx) 80 60 • Systemic insecticides are not effective on 40 larger trees (> 15 inch DBH) No. of Adults of No. 20 – Imidacloprid (Merit) 0 – Thiamethoxam (Flagship) 7-Jul 22-Jul 6-Aug 3-Sep 27-May 10-Jun 23-Jun 18-Aug 17-Sep – Disufulton (Disyston) Date 2003 2004

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Management Management Number of exit holes per tree pre- and post- treatment 90 • Destroying infested 80 trees via chipping is 70 Imid an effective 60 Disyst Nov. 2002 management 50 UNT Nov. 2003 40 strategy to aid in the Oct. 2004 30 Thiam prevention of further 20 infestations Mean# Exit Holes/Tree 10 0 1 2 3 4 UNT Treatment UNT

Chipping study: Number of emerged adults, 2004 25

20 Log- inside

15 Log- outside

5 Bandit 90 Bandit 250 Mean# Adults/Tree 0 1 2 3 4 Treatment

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Gypsy Moth

• Exotic, Invasive Species • Native to Europe, Asia, and Africa • Accidentally released by L. Trouvelot near Medford, MA in 1869

Gypsy Moth • Gypsy moth slowly moved westward across the U.S. causing measurable damage since the early 1900’s • Movement has been exacerbated by transportation advancements (we humans are largely responsible) • First discovered in WI in 1971 • > 50 counties in WI are currently quarantined

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Gypsy Moth Biology

• Caterpillars are the damaging life stage • Younger larvae (1st and 2nd instars) are diurnal (day) and nocturnal (night) • Older larvae (3rd-5th instars) are nocturnal • Larvae feed on > 350 species of plants

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Common Hosts in Wisconsin Gypsy Moth Biology

• Oaks (most species) • Adult females can NOT fly (no wing muscles) • Aspens • Adult females lay egg masses that contain • Willow 400-1000 eggs • Apple/Crabapple • All life stages can be transported via human activity • Paper birch • Only ONE generation per year • Mountain Ash • Basswood and Linden

Chemical Control Options

• Carbaryl (Sevin) • Permethrin (Ambush) • Acephate (Orthene + Lepitect) • Bifenthrin (Onyx Pro) • Bacillus thuringiensis kurstaki • Cyfluthrin (Decathalon) (Btk) = Dipel • Lambda-cyhalothrin (Scimitar) • Spinosad (Conserve) • Deltamethrin (DeltaGard) • Insecticidal Soap • Chlorantraniliprole (Acelepryn) • Diflubenzuron (Dimilin) • Phosmet (Imidan) • Tebufenozide (Confirm) • Indoxacarb (Advion) • Azadirachtin (Azatrol) • Golden Pest Spray Oil (GPSO)

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Effectiveness of Chemical Insecticides Controls Product Residual AcXvity • Most products provide excellent control when applied Acephate* 10-21 days correctly AzadirachXn 14-21 days • Some products must be applied to young caterpillars Btk 7-10 days • Some products have quicker knockdown and speed of kill Bifenthrin 7-10 days • Some products must be ingested while others work on Carbaryl 3-10 days contact Beta-cyﬂuthrin 7-10 days Deltamethrin 7-14 days • Some products have longer residual activity while others Diﬂubenzuron (IGR) Season-long must be re-applied InsecXcidal Soap < 24 hours • Lepitect is a plant systemic, great for larger trees that are a Permethrin 7-10 days challenge to spray! Spinosad 7-14 days Tebufenozide (IGR) Season-long

Golden Pest Spray Oil Gypsy Moth Control Options

• Soybean oil based product (93%) and a surfactant • Biological (Pathogens, Parasites, Predators) (7%) • Cultural (Mechanical/Physical) • Apply directly (oil) to egg masses (1:1 ration of • Chemical (Insecticides) GPSO + Water – Add food coloring to indicated eggs treated! • > 95% control when applied September-April until 3 days prior to egg hatch

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Biological Control Options Biological Control Options

• Fungi • Viruses • Parasitoids – Entomaphaga – NPV – Wasps and flies maimaiga • Transmitted via female – Fungal pathogen, to offspring infects young larvae – Spores are spread via wind

Biological Control Options Cultural Control Options

• Predators • Plant Health (fertility and water) – Mammals • Sanitation • Mice • Voles • Destruction of Egg Masses • Chipmunks • Squirrels • Banding – Insects – Barrier • Beetles – Hiding • Ants • Stink Bugs

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Sanitation • Maintain a clean property Destruction of Egg Masses – Remove dead branches and stumps – Inspect RVs, lawn furniture, siding, play stations, • Scrape and remove eggs etc. • Destroy eggs by freezing or burning

Fall Webworm Banding • Barrier • Hiding – Place burlap around tree, – Place furnace tape remove and destroy around tree, coat with tangle foot larvae daily

MulXple reports to Insect DiagnosXc Lab from across the state

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Biology Damage Symptoms

• Adult females lay eggs on the underside • Feeding damage is similar to Eastern of leaves in masses (mid-March-May) Tent Caterpillars, however they are • Adults cover eggs with white hairs present in the FALL and their nests are • Eggs hatch in late-summer/early-fall located on terminal branches • Larvae begin constructing nests and feeding on leaves

Management Viburnum Leaf Beetle (VLB) • Pyrrhalta viburni (Chrysomelidae) • Physical removal of nests • European origin • High populations may require – Detected in Ontario-1945 insecticide treatments can be applied to – Detected in New England-1990’s INSIDE of web-like nests • Skeletonizes Viburnum spp

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Viburnum Leaf Beetle in WI Biology

• Detected in Dane County, May 2009 • ONE generation per year – Origin: Infested nursery stock • Adult females lay up to 500 eggs – Eliminated plants • Both larvae and adults cause feeding damage – No further acXvity (skeletonization)

• Detected in Milwaukee County, late August 2014 – Damage noXced on well-established bush – Origin: unknown??

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Oviposition Scars Management

• Plant resistant varieties – Koreanspice viburnum, doublefile viburnum, leatherleaf viburnum, tea viburnum, Siebold viburnum • Physically remove egg-infested twigs • Barrier bands (sticky) to capture crawling larvae • Apply contact insecticides to newly hatched larvae (late April – early May)