IN THIS ISSUE: LaceBugs:Pages2-4

VerticilliumWiltofTreesandShrubs:Pages4-6HydrangeaAnthracnose:Pages7-8

TEST YOUR MASTER GARDENER SKILLS (Answeronpage8)

IdentifythesewhitespotsonaMustardGreenLeaf!

WEEK 3: JULY 17-24

IMAGE FROM HELPDESK

PleasereferonlytothecurrentVCEPest

ManagementGuide:HomeGroundsandAnimalsforpesticiderecommendations.All

pesticidesrecommendedareattheriskofthe

user.Readandfollowalllabelinstructionsforuse,storage,anddisposal.

Remember,thepesticidelabelisthelaw.

LACE BUGS

IMAGE FROM UNIVERSITY OF

FLORIDA AZALEALACEBUG

Symptoms:• Yellowspotsonupperleaf

surfacesthatseemtolooklikemitedamagebutwithbiggerspots

• Severefeedingresultsingrayishblotchesorcompletelybrownleaves

• Brownvarnishtypedroppingsontheleaf’sunderside

IMAGE FROM RUTGERS UNIVERSITY OAKLACEBUGEGGS

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IMAGE FROM UNIVERSITY OF CALIFORNIA,

IRVINE SYCAMORELACEBUG

IMAGE FROM UNIVERSITY OF FLORIDA AZALEALACEBUGDAMAGE

LACE BUGS (CONT.)

Relevance:EggshatchinMayand1-2generationsoccurbythesummer’send

Knowingtheplantspecieswillhelpyouidentifythelacebugspecies.Belowisalistofcommonlacebugandtheirrespectivehostplants.ThoseboldedaretheonesmostprevalentinVirginia.

AndromedaLaceBug JapaneseAndromedaAzaleaLaceBug Azaleaandmountainlaurel

RhododendronLaceBug RhododendronandmountainlaurelAlderLaceBug Alder,hazel,elm,birch,andcrabapple

BrasswoodLaceBug BrasswoodandlindenBirchLaceBug Yellowbirch,whitebirch,beech,willow,mountainash,mapleandeastern

hophornbeamBuckeyelacebug BuckeyeElmlacebug Americanelm

Hackberrylacebug HackberryHawthornlacebug Hawthorn,quince,pyrancantha,cotoneaster,andserviceberry

Oaklacebug OakSycamorelacebug SycamoreandLondonplanetreeWalnutlacebug Blackwalnut,butternut,andlinden

Willowandpoplarlacebug Willow,balsampopular,bigtoothaspen,andquakingaspenWillowlacebug Willow

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Description:adultsare1/8”to1/4”inchlongwithanetlikepatternonthewings.Inaddition,theirwingsaredottedwithbrownandblack.Lacebugeggs

areelongatedandcylindricalshapes.

DamagetoPlants:Lacebugfeedingisdirectlyharmfultoplants

MoreResourcesforLaceBugControl

VCEPestManagementGuide:HomeGroundsandAnimalsVCEExtension:LaceBugsUMDExtension:LaceBugs

PennStateExtension:LaceBugsonBroad-LeavedEvergreenOrnamentalPlantsPennStateExtension:LaceBugonDeciduousWoodyOrnamentalPlants

VERTICELLIUM WILT OF TREES AND SHRUBS Relevance:SymptomsofdiseasearemoreapttoappearinJulyandAugust

Why:Causedbysoil-bornefungi,Verticilliumalbo-atrumandVerticilliumdahliae.Thefungusiscommoninmanysoilsbutpreferscertainhoststhatincludetrees,shrubsandevenvegetablesespeciallythetomatoplant.BelowisatableofcommontreesandshrubssusceptibletoVerticilliumWilt.

Ash Maple Honeysuckle RussianOlive SmoketreeAzalea Elm Linden Plum SpireaJapaneseBarberry

Dogwood BlackLocust Redbud Sumac

Catalpa Elder Magnolia Rose ViburnumCherry,otherstonefruits

CurrantandGooseberry

KentuckyCoffeeTree

Oak,pineandred(rare)

Weigela

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BestControlMethods:• Monitorplantsregularlyinspringforlacebugsigns

• PlantAzaleaandRhododendroninashadyareatoavoidheavylacebugpopulations

DamagetoPlants:Seriousdiseasesincethefungispreadsinternallyorsystematicallywithintheplantandcanleadtoplantdeath

Symptoms

• Small,yellowfoliage• Leafscorch(marginalbrowning)• Slowgrowth• Abnormallyheavyseedcrops• Oftenonebranch/side/sectionis

affected• Someexhibitelongate,dead

areasofbarkondiseasedbranches/trunks

• Diebackofshootsandbranches• Leafcurling,drying• Abnormalredoryellowcolorof

leavesorinareasbetweenleafveins,partialdefoliation,wiltingandbranchdieback

• Inwiltingbranches,therearediscoloredstreaksinbark

a) Greentoblackinmaplesb) Browninelmsc) Browntoblackinblacklocust

andothertrees

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IMAGEFROMPURDUEUNIVERSITYVERTICELLIUMONMAPLE

IMAGEFROMUMASSAMHERSTVERTICELLIUMONGREENASH

BestControlMethods• Donotreplantsusceptiblespecieswhereaspecimenwaskilledby

VerticilliumWilt• Pruneoutaffectedlimbs;waterandfertilizetomaintaintreevigor• NeverusewoodchipstakenfromaVerticilliuminfectedtreeasmulchor

pottingmedium• Topreventspread,disinfecttools

MoreResourcesforVerticilliumWiltControl

UniversityofMinnesotaExtension:VerticilliumwiltoftreesandshrubsPennStateExtension:VerticilliumWiltofWoodyOrnamentals

MissouriBotanicalGarden:VerticilliumWilt

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IMAGE FROM MICHIGAN STATE

UNIVERSITY VerticilliumonNorway

maplewithgreendiscoloration

HYDRANGEA ANTHRACNOSE

• Circularorirregularlyshapedbrownspots

• Spotsturnfromlightbrowntotan

• Spotshaveabull’seyeappearance

• Spotsbecomeangularoncetheyhavereachedlargeleafveins

Relevance:Hydrangeaanthracnosefavorshotandwetconditions.

Why:CausedbythefungusCollectotricbumgloeosporioides,whichcanattackboththeleavesandbloomsofthehydrangea.Heavilyfertilizedhydrangeas

maybemostsusceptibletoattackbyC.gloeosporioides.

Symptoms:

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IMAGES FROM THE MASTER GARDERNER COORDINATOR ANTHRACNOSEONHYDRANGEAS

TEST YOUR MASTER GARDENER SKILLS

Answer:ThewhitespotsareAphideggsandlarvae!

Aphidsaresoft-bodiedinsectsthataremainlygreenorblack.However,therearehundredsofspeciesandthese“plantlice”canalsobelavender,gray,brown,pink,redoryellow.Acommoncharacteristicbetweenallspeciesisthepresenceoftwotubes,calledcornicles,onthebackendsoftheirbodies.Aphidsfeedinclustersandgenerallyprefertofeedonnew,succulentshootsorleaves.Lightinfestationsareusuallyharmlesstotheplantsbutheavyinfestationscanresultin:

• Leafcurl• Wilting• Stuntingofshootgrowth• Delayinfruit/flowerproduction

• Atransmissionofpathogenstoplants

• Honeydew(aphidexcrement)buildupwhichcanleadtosootymold

BestControlMethods:Collectanddiscarddiseasedbloomsandleaves

Takingcuttingsfromsymptom-freeplantswillpreventspreadLimityourtimegardeninginwetconditionssincesporesprimarilyspread

throughsplashingwater

MoreResourcesforHydrangeaAnthracnose:AlabamaCooperativeExtensionSystem:DiseasesofHydrangea

TennesseeStateUniversity:FoliarDiseasesofHydrangeasPestManagementGuide:HomeGroundsandAnimals

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BestControlMethods:Maintainplantvigor

PlantflowersthatattractbeneficialpredatorslikeLadyBeetles,lacewings,damselbugs,flowerflymaggots,certainparasiticwasps,andbirds

MoreResourcesforControllingAphids:VCEExtension:Aphids

OregonStateExtension:HowtocontrolaphidswithlesstoxicmethodsPermacultureResearchInstitute:PlantsthatAttractBeneficialInsects

PestManagementGuide:HomeGroundsandAnimals

THANK YOU FOR READING!

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