2016 Virginia Tech 2904-1290 (ENTO-200NP)
EmeraldAshBorer
EricR.DayandScottSalom,Dept.ofEntomology,VirginiaTechPlantsAttacked:Emeraldashborer(EAB)attacksallspeciesofashtreesthatgrowinVirginia.OnlyAsianspeciesofashtreeshaveshownanyresistancetothispest.EABisbecomingwidespreadinVirginia.
DescriptionofDamage:Thefirst indicationofdamage by the emerald ash borer is cracks inthebranch’shighinthetreefollowedbycanopydieback.Tunnelingby the larvaecausegirdlingand death of branches and the trunk. Earlyfeeding damage by emerald ash borer will bedifficult to detect because trees show fewsymptoms.WoodpeckersfeedingonEABlarvaeleave holes in the bark that can be seen bylooking up into the tree. As the infestationprogresses the trees starts to thin out andbranches inthetopsectionsofthetreestarttodie.Manytreeswillhavealargenumberofnewshootsonthetrunkcalledepicormicbranching.Oftenthesebranchesoccuratthejunctionofthelive and dead sections of the trees. Epicormicbranchingmayalsooccuratthebaseofthetreeafterthetreehasdied.EABcanliveintwigsassmallas1inchindiameterbutcanalsobreedintrunksoffullymaturetrees.Itusuallytakes2-5years for damage to be noticed and the EABdamagekillsthetreeshortlythereafter.Identification:Adultbeetlesareabout1/2inchlong and bright metallic green in color. Whenthewings are spread, the exposed abdomen ispurple-red in color. The larvae are creamywhite and have a tan head. At the end of theabdomenisapairofpincherlikeprojection.EABcanalsobeidentifiedbyitsdamage.Astheadultbeetleexits its gallery from under the bark it leaves a characteristic “D” shaped exit hole about 1/4 inch indiameter.Removing thedeadbarknear theexitholewill revealnumerous “S”shaped tunnelsunder thebark in the cambiumarea.Woodpeckerswill oftenvisit infested treesand leave large jaggedholes afterthey have fed on the EAB larvae. Unfortunately they do not provide complete control for this pest.Coleoptera:Buprestidae,AgrilusplanipennisFairmaireLifeHistory:Theemeraldashborerhasaonetotwo-year lifecycle.Theadultbeetlesstartemerging inMayandearlyJuneandbeetleactivitypeaksbetweenmid-Juneandearly-July.ItispossibletoseebeetlesaslateasAugust.Beetleslivefromabout3-6weeks,feedonfoliagebymakingsmallnotchesontheouter
edge.Thefemaleusuallylaysbetween50-100eggsone at a time in bark cracks and crevices. Eggshatch in about a week and the newly hatchedlarvae borer though the bark down into thecambium layer under the bark. Larvae feed underthe bark during the summer and they are usuallydonebyfallbutstayinthelarvalstageuntilspringwhen they pupate. Newly molted adults remainunder the bark for a fewweeks until emerging tostarttheylifecycleagain.Ifdegree-dayinformationisavailable,EABadultsstartemergingatabout500degreedays(base50degreesF.)andthepeakisatabout1000degreedays.Control: Infested treesrarely recoverandneed tobe removed and destroyed or chipped as soon aspossible. Non-infested ash trees can be treated toavoid infestationbut it’shard topredictwhen theemeraldashborerwillarriveinaparticularcountyorcity inVirginia. Ifyou live inan infestedcountyor an adjacent county you may want to considerusing a systemic insecticide, applied as a soildrench a the base of plant in May or early Junebeforethetreebecomesattacked.SeeAlso:EmeraldAshBorerControlforForestersandLandowners,VaCoop.ExtensionPublication:ENTO-76NP,http://pubs.ext.vt.edu/ENTO/ENTO-76/ENTO-76.htmlContact your local Cooperative Extension office tosee if your location is infested or near an infestedcounty. Your extension office can also provide themost current information on chemicals labeled forcontrol.ParasitoidwaspshavebeenimportedfromChina and released in numerous locations. Asreleasescontinueefficacyofthewaspsasbiologicalcontrolagentsisbeingassessedanditishopedtheywillcontribute toEABcontrol incombinationwithothertactics.Movement of Firewood: Emerald ash borer hasbeendetectedandmovedbyfirewoodintheUnitedStatesandthusitsimportanttoremoveanddestroyinfestedash treesonsite. It’salso importantwhencamping to leave firewood at home and purchasefirewoodatthecampgroundfromlocalsources.Remarks: The emerald ashborer is native toAsiaandwasfoundinMichiganin2002.Itisnotknownhow it was brought into this country. The firstinfestationinVirginiain2003waseradicatedbutitwasfoundagainin2008andby2016wasfoundin25countiesscatteredthroughoutVirginia.
