Understanding and Managing Topics in Today’s Presentation: Wisconsin’s Most Menacing ▪ Trending or significant plant pests from 2020 Landscape Insect Pests of 2020 ▪ EAB, viburnum leaf beetle, gypsy moth, Japanese beetle, etc.

▪ Other notable insects PJ Liesch ▪ Minor/occasional pests, in the news UW-Insect Diagnostic Lab Twitter: @WiBugGuy ▪ On the radar: pests to watch for [email protected]

University of Wisconsin–Madison University of Wisconsin: Insect Diagnostic Lab Insect Diagnostic Lab 2 1 2

Map Sources: WI-DATCP Emerald Ash Borer (Agrilus planipennis)

Six new county-level detections in 2020: Dunn, Florence, Oconto, Pepin, Price, University of Wisconsin–Madison Shawano University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab 3 4 3 4

EAB Biocontrol Efforts EAB Chemical Controls ▪ 2021: USDA ending federal quarantine; shifting efforts to biological control

Tetrastichus planipennisi Spathius agrili

University of Wisconsin–Madison University of Wisconsin–Madison Insect DiagnosticOobius Lab agrili Insect Diagnostic Lab 5 6 5 6 Viburnum Leaf Beetle (Pyrrhalta viburni) Trending: Viburnum Leaf Beetle ▪ Leaf beetle native to Europe; introduced to eastern Canada 1940’s ▪ Northeast US in 1990’s; Wisconsin in 2014 ▪ Also in Pacific NW ▪ Adults and larvae skeletonize foliage of viburnum shrubs

Adults: ~1/4” long; yellowish-green colour

Larva: ~1/3” long; pale with University of Wisconsin–Madison pattern of spots; dark head University of Wisconsin–Madison Insect Diagnostic Lab capsule and 6 legs Insect Diagnostic Lab 7 8 7 8

VLB Damage Viburnum Leaf Beetle Biology ▪ ONE year life cycle ▪ Both larvae and adults feed on foliage ▪ Overwinter as eggs; larvae emerge in April/May and feed ▪ Adult ♀ also chew pits in twigs ▪ Larvae walk down to soil to pupate; adults emerge in June/July ▪ Adults feed and ♀ lay up to 500 eggs (in pits of 5-8 eggs) Oviposition pits

Oviposition damage (twigs)

Mating Adults

Skeletonization damage Larval feeding and skeletonization University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Severe damage Insect Diagnostic Lab 9 10 9 10

Viburnum Leaf Beetle Management Lily Leaf Beetle (Lilioceris lilii) Cultivar Selection ▪ Cultural ▪ Choosing less-susceptible cultivars ▪ Also known as the “scarlet lily beetle” ▪ Maintain plant vigor ▪ Leaf beetle native to Europe; introduced to eastern Canada 1940’s

▪ Physical ▪ Northeast US in 1990’s; Wisconsin in 2014 ▪ Prune out egg sites ▪ Cause significant damage to true lilies (not daylilies) ▪ Removal/replacement of damaged plants Larvae: ~1/3” long; yellow body; cover themselves with excrement ▪ Biological giving a slimy appearance ▪ Limited research to date

▪ Chemical ▪ Foliar insecticide sprays targeting larvae in spring and adults in summer ▪ Systemic insecticides in spring

University of Wisconsin–Madison AdultsUniversity: ~1/3” long; of Wisconsin–Madison bright red Insect Diagnostic Lab colour;Insect “squeak” Diagnostic when Labpicked up 11 12 11 12 Trending: Lily Leaf Beetle Lily Leaf Beetle Host Plants ▪ True lilies: Asiatic, Oriental, Easter, Turk’s cap, Tiger, & Wood lilies ▪ Also eat: Fritillaries & Solomon’s Seal ▪ Don’t eat canna lilies, calla lilies, or daylilies

True lilies Calla Lily Solomon’s Canna Lily Seal

Fritillaries

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab Daylilies 13 14 13 14

LLB Damage Lily Leaf Beetle Biology

▪ Both larvae and adults feed on foliage Severe damage ▪ ONE year life cycle ▪ Overwinter as adults; mate and lay eggs in spring ▪ Larvae feed and camouflage themselves; head to ground to pupate ▪ Adults feed and ♀ lay 400+ eggs (in batches of 8-12) Larvae

Damage of small larvae

Eggs Cocoon Stage (in soil)

Adults (mid-summer) Holes in Winter leaves University of Wisconsin–Madison University of Wisconsin–MadisonMating Adults Insect Diagnostic Lab Adult Feeding Insect Diagnostic Lab(Spring) 15 16 15 16

Lily Leaf Beetle Management Gypsy Moth (Lymantria dispar)

▪ Cultural ▪ Native to Europe and northern Asia; introduced in 1860’s ▪ Choosing less-susceptible species/cultivars ▪ Range expanding westward and southward ▪ Maintain plant vigor ▪ Outbreaks at leading edge of expansion Gypsy Moth Adult ▪ Physical ▪ Major defoliator of hardwood trees Female w/Egg Mass: ~1.5” long ▪ Hand-picking or squishing ▪ Significant invasive species! ▪ Removal/replacement of infested plants Gypsy Moth Caterpillar: Up to ~2” long ▪ Biological ▪ Parasitoid wasps released in northestern US ▪ Limited impact thus far

▪ Chemical ▪ Contact insecticide sprays targeting larvae and/or adults

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab 17 18 17 18 Trending: Gypsy Moth Recent Trends:

▪ Distinct uptick in gypsy moth numbers in 2020 ▪ Why was gypsy moth activity up in 2020? ▪ DATCP: GM populations are “intermediate” ▪ Mild winter 2019-20 (decreased egg mortality)

▪ Drier conditions in 2020 (decreased Entomophaga)

▪ What to expect in 2021…???

▪ Polar vortex impacts

▪ Spring weather patterns impact Entomophaga

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab 19 20 19 20

Gypsy Moth Quarantines Gypsy Moth: Physical Control

▪ Egg Masses: inspect for and scrape away ▪ Late summer through the following spring ▪ Sticky Band: to target very young caterpillars ▪ Burlap Band: to target larger caterpillars, which hide during the day

Burlap Band Method

University of Wisconsin–Madison UniversitySticky of Wisconsin–Madison Band Insect Diagnostic Lab Insect DiagnosticMethod Lab 21 22 21 22

Gypsy Moth: Biological Control Gypsy Moth: Chemical Control ▪ Fungus: Entomaphaga maimaiga ▪ Conventional foliar sprays: acephate, bifenthrin, carbaryl, chlorantraniliprole, cyfluthrin, cypermethrin, deltamethrin, lambda- ▪ Brought from Japan in early 1900’s; not effective until 1980’s! cyhalothrin, permethrin, spinosad, … ▪ Spores are spread via wind; infects young larvae

▪ Virus: NPV ▪ Systemic products: acephate, chlorantraniliprole, clothianidin ▪ Can be transmitted to eggs by ♀ ▪ Alternative products: Bacillus thuringiensis kurstaki (Btk), SPLAT- ▪ Predators/Parasites: GM (pheromone), insecticidal soap, horticultural spray oil ▪ Parasitoid wasps & flies ▪ Predatory ground beetles & stink bugs Mating Disruption with SPLAT-GM ▪ Mice

University of Wisconsin–Madison University of Wisconsin–Madison Aerial spraying Insect Diagnostic Lab Insect Diagnostic Lab with Btk 23 24 23 24 Japanese Beetle (Popillia japonica) Trends in Wisconsin ▪ Scarab beetle from Japan; detected in New Jersey in 1916 ▪ Well established in ▪ Found across much of eastern US; some pockets in West southern WI ▪ Adults: above ground foliar feeder ▪ Can occur in “pockets”

▪ Gaining footholds in northern WI

▪ Populations highly variable in 2020

Map Credit: Google Maps

Adults:University ~1/3” long; of copperWisconsin–Madison & green colored; University of Wisconsin–Madison Larva: soil-dwelling white grub white spotsInsect along Diagnostic side of Lab body Insect Diagnostic Lab 25 26 25 26

Japanese Beetle Biology Japanese Beetle Damage

▪ ONE year life cycle ▪ Adults emerge ~June/July in Midwest; active into September ▪ Adults are sun-loving, gregarious insects; strong fliers ▪ Adults are skeletonizers, NOT true defoliators ▪ Attack 350+ plant species; can feed on leaves/fruit/flowers ▪ Lindens ▪ Apple/Crabapples ▪ Horsechestnut Skeletonization ▪ Roses ▪ Cherries ▪ Willows ▪ Birch ▪ Maples ▪ Corn ▪ Grapes ▪ Elms ▪ Asparagus… ▪ Beans ▪ Hibiscus

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab InsectFeeding Diagnostic on flowers Lab Significant Japanese beetle Damage 27 28 27 28

Managing Japanese Beetles & Their Damage Japanese Beetle: Cultural Control

▪ Many factors can influence management approaches: ▪ Manipulation of the local environment to prevent pest ▪ Time/worker availability? problems or reduce the amount of damage ▪ How many plants are affected? ▪ How large of an area? ▪ Plant location in the landscape ▪ Size of the plants? ▪ Preferences—aesthetics, organic, etc. ▪ Choosing less-preferred plants ▪ Maintain plant vigor Management Scenarios: ▪ Tolerance 1. Turfgrass 2. “Small” plants (gardens, flowers, shrubs, small trees) ▪ Turf: proper turf care (fertility, mowing, irrigation) 3. “Large” plants (trees)

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab 29 30 29 30 Japanese Beetle: Physical Control Japanese Beetle: Biological Control ▪ Physical activities performed to help prevent or reduce pests ▪ Many natural enemies feed on or attack Japanese beetles,

Photo Credit: Whitney Cranshaw, Bugwood.org but don’t have much overall impact: ▪ Hand-picking ▪ Predators Predator: Crow digging for grubs ▪ Squishing ▪ Parasites ▪ Barriers/row cover ▪ Pathogens ▪ Traps

Parasite: Winsome Fly Photo Credit: Marie-Lan Nguyen via Wikipedia Pathogen: Milky Spore Disease Traps: helpful for monitoring; (Paenibacillus popilliae) little/no meaningful control of Japanese beetles in most situations

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Photo Credit: Aaron Baugher, via flickr Photo Credit: WhitneyInsect Cranshaw, Diagnostic Bugwood.org Lab 31 Photo Credit: David Cappaert, Bugwood.org32 31 32

Chemical Controls Chemical Control: Small Plants ▪ Foliar applications of contact insecticides typically used ▪ Applications to blooming flowers pose risks to pollinators ▪ Short residual activity Organic Conventional ▪ Insecticidal soap* ▪ Carbaryl ▪ Horticultural oils (neem, etc.)* ▪ Each approach uses different products and/or tactics ▪ Bifenthrin ▪ Cyfluthrin ▪ Azadirachtin ▪ Targeting one life stage has small impacts on the others ▪ Cyhalothrin ▪ Pyrethrins ▪ Focus on the plant(s) you’re trying to protect ▪ Cypermethrin ▪ Bacillus thuringiensis galleriae ▪ Deltamethrin ▪ Permethrin University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab ▪ ChlorantraniliproleInsect Diagnostic Lab 33 34 33 34

Large Plants (Trees); Certain Shrubs Dogwood Sawfly (Macremphytus tarsatus)

▪ Systemic products can be applied preventatively ▪ Native pest with a single generation in mid-late summer ▪ Typically applied as a soil drench ▪ Wasp-like adults; larvae feed on dogwoods (Cornus spp.) ▪ Ex. Imidacloprid Larvae: up to ~1” long

Black and yellow coloring; often ▪ Can take several weeks for uptake in large trees covered by whitish waxy coating Adult

▪ Can pose risks to bees ▪ Wait until after plants have bloomed to apply if possible ▪ Can’t use on lindens due to pollinator concerns

Do not apply this product, by any application method to linden, basswood, or other Tilia species

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab Larvae 35 36 35 36 Dogwood Sawfly Damage Dogwood Sawfly Adult Dogwood Sawfly ▪ Only feed on dogwoods (Cornus spp.) Life Cycle

▪ Chew notches in leaves; consume entire leaves Only one generation per year ▪ Occasional complete defoliation; plant death rare ▪ Overwinter as pupae ▪ Wood damage to homes/structures occasionally observed… ▪ Adults emerge May-July ▪ Mate and lay eggs in

▪ Larvae typically noticed in mid- Eggs laid in late summer dogwood leaves

▪ Leave plants to excavate small pupal chamber in soft wood Dogwood sawfly larvae

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab 37 38 37 38

Dogwood Sawfly Control Magnolia Scale ▪ Cultural ▪ Host plant: Magnolias ▪ Maintain plant vigor ▪ Covered with a waxy powder ▪ Choose non-preferred hosts (they only like dogwoods…) ▪ Major problems in 2015 & 2016 ▪ Physical ▪ Increased pressure in 2019 & 2020 ▪ Physically remove or squish larvae (check undersides of leaves)

▪ Chemical ▪ Conventional foliar sprays: acephate, bifenthrin, carbaryl, cyfluthrin, cypermethrin, deltamethrin, lambda-cyhalothrin, permethrin ▪ Low impact sprays: insecticidal soap, light horticultral oils, pyrethrins, neem oil, spinosad ▪ Bacillus thuringiensis kurstaki (BTK) won’t work (not a true caterpillar!)

Credit: William Fountain, Bugwood.org University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab 39 40 39 40

GDD: 2155 - 2800 Soft Scales Timing is Everything! Date: Late August - September

▪ Lack detachable cover ▪ Juveniles (“crawlers”)—most vulnerable life stage ▪ Often with plump appearance ▪ Insecticide sprays targeting crawlers can be very effective ▪ High reproductive capacity ▪ Many species can be predicted using Growing Degree Days ▪ Produce lots of honeydew ▪ Can attract ants, wasps, sap beetles, etc. ▪ Growth of black sooty mold

Credit: Lacy L. Hyche, Bugwood.org Scouting: • Magnified examination • “Notepad” method University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect• “Tape” Diagnostic method Lab 41 42 41 42 Magnolia Scale Control Magnolia Scale Biological Control

▪ Physical Control: ▪ Several generalist predators can feed on scale insects ▪ Remove heavily infested plants ▪ Specialized parasitoid wasp can cause high mortality ▪ Selectively prune heavily infested portions of plants ▪ Outbreaks typically controlled within a few years ▪ Beneficials can be impacted by insecticides ▪ Chemical Control: ▪ Dormant oil ▪ Contact insecticides (2100-2800 GDD) ▪ Systemic products

University of Wisconsin–Madison University of Wisconsin–MadisonPredatory Lady Beetle Larvae Insect Diagnostic Lab Insect Diagnostic Lab Parasitoid Wasp 43 44 43 44

Lacebugs (Tingidae) Lacebug Damage & Control

▪ Several species in the Midwest ▪ Yellowing or stippling of foliage ▪ Occasional pest ▪ Can resemble spider mite ▪ Numerous hosts: azaleas, oak, damage elm, birch, crabapple, linden, ▪ Black fecal spots often present aspens, willows, roses, and others

▪ White or black colored; wings with Lacebug Nymphs on ▪ Often on undersides of leaves Underside of Leaf lace-like pattern; adults ~1/8-1/4” ▪ Nymphs smaller and spiky ▪ Commonly controlled with ▪ Typically overwinter as adults (and contact insecticides some eggs); multiple generations per year; can be found into the fall

University of Wisconsin–Madison Adults Nymphs University of Wisconsin–Madison Stippling Insect Diagnostic Lab Insect Diagnostic Lab Damage 45 46 45 46

On the Radar: Box Tree Moth On the Radar: Spotted Lanternfly ▪ Invasive pest from Asia; introduced to Europe 2006 ▪ Invasive pest from Asia; introduced to US in 2014 ▪ By 2020: have decimated boxwoods around Europe ▪ Attacks a range of trees ▪ Detected in Canada: Toronto, Canada 2018 ▪ Eggs easily transported ▪ Caterpillars defoliate plants, create webbing

Spotted Lanternfly Egg Masses Box tree moth caterpillar Spotted Lanternfly Adult

Adult box tree moth

University of Wisconsin–Madison University of Wisconsin–Madison Insect Diagnostic Lab Insect Diagnostic Lab 47 48 47 48