Monitoring in depth - New York Invasive Species Clearinghouse

Monitoring in depth - New York Invasive Species Clearinghouse


© P.E. Wiseman, Virginia Polytechnic Instituteand State UniversityEmerald Ash Borer:MonitoringModule ObjectivesThis module will provide an overview of the methods and proceduresused to monitor ash trees for EAB infestation and explain how citizenmonitorsshould respond upon discovering a suspected EAB infestation.Upon completing this module, youshould be able to:• Explain the importance of earlydetection of EAB infestation tominimizing its spread and itsimpacts on forest resources• Describe the tools and techniquesused to monitor ash trees for EABinfestation• Perform a visual inspection of avulnerable ash tree anddocument your observations• Explain how and where to report asuspected EAB infestation

Emerald Ash Borer:MonitoringMonitoring for Early Detection and Rapid ResponseA fundamental practice for managing anyinvasive pest is monitoring –periodic,systematic inspection of vulnerable trees todetect and document pest activity.Effective monitoring is crucial for earlydetection and rapid response to an EABoutbreak in a community. Management ofEAB is more effective the earlier aninfestation is detected.The prospect of monitoring trees for EABinfestation in an entire community is aformidable challenge.Over the last few years, federal and stateagencies have deployed extensive EABmonitoring programs throughout the easternU.S. in an effort to rapidly detect outbreaks.© Mark Whitmore, Cornell University

Emerald Ash Borer:MonitoringMonitoring (continued)EAB can be spread long distances byhuman activity. In addition,government resources for monitoringEAB are limited, so the likelihood of alocalized outbreak going undetectedis high.Additional monitoring by citizens andgreen industry professionals canincrease the odds of detecting a localEAB outbreak quickly.One example of citizen monitoring isthe EAB First Detector program fromCornell Cooperative Extension.Citizens are trained to identifyinfestations and educate theircommunities. This has significantlyincreased the capacity of New Yorkcommunities to monitor for EAB.© Michigan Department of Agriculture,

© Jared Spokowsky, New York State Department ofAgriculture and Markets, Bugwood.orgEmerald Ash Borer:MonitoringReviewWhat is monitoring?AnswerWhy bother withearly detection?Answer

© David Cappaert, Michigan State University, Bugwood.orgEmerald Ash Borer:MonitoringWhere to Look for EABFor EAB monitoring to be efficient andproductive, it is important to knowwhere vulnerable ash trees arelocated.Many communities possess a treeinventory – a database containinginformation about the location andcharacteristics of individual publictrees – that can be used to identifyvulnerable trees and facilitate EABmonitoring efforts.With information about the quantityand location of ash trees in acommunity, a systematic monitoringprogram can be developed toinspect trees on a periodic basis.

Emerald Ash Borer:MonitoringWhere to Look for EAB (continued)Communities lacking a tree inventorycan quickly locate vulnerable ashtrees using a windshield survey, inwhich a team of trained assessorsdrives slowly along select streets andrecords tree locations (a GPS unit isvery helpful) for follow-up inspectionby monitors traveling on foot.Volunteers trained in ash speciesidentification and data collection canalso be organized to conduct an onthe-ground,ash-only inventory tolocate and document vulnerable ashtrees for later inspection by monitors.At the same time they can alerthomeowners and offer outreachmaterials, or doorhangers.© Mark Whitmore, Cornell University

Emerald Ash Borer:MonitoringWhere to Look for EAB (continued)EAB can be detected in infested trees yearround.You can see woodpecker foraging on ashall year round but recent activity is mosteasily detected in late winter or earlyspring,You can positively identify ash specieswhen their leaves are present, but usingbark and twig structure makes winter ID ofash a snap.You can detect canopy thinning, branchdieback, and epicormic sprouting whentrees are foliated.You can find adult beetles (the most visiblelife stage outside the tree) are active fromMay to August when they may be foundmating, laying eggs, or eating ash foliage.© Mark Whitmore, Cornell University

Emerald Ash Borer:MonitoringWhich Trees to Monitor?In a community with hundreds ofash trees, it is a challengedeciding which trees to monitor.It is best to monitor them allbecause you never know wherean infestation may originate.However, if you must prioritize,research indicates that EAB maypreferentially attack trees basedon the following three criteria:green ash• Species• Location• Stresswhite ash

© Mark Whitmore, Cornell UniversityEmerald Ash Borer:MonitoringWhich Trees to Monitor? (continued)Species – green ash appears tobe most preferred by EAB,followed by black ash, whiteash, and blue ash.Green and white ash are thespecies most commonly foundin New York’s rural forests andplanted in urban forests as streetand shade trees.Location – ash trees growing inopen, sunny locations are morelikely to be attacked by EAB.Lawn and park trees often residein these conditions.

Emerald Ash Borer:MonitoringWhere in the Tree are Clues for EAB?It is difficult to detect an infested ash treeduring its first year of infestation becauseEAB density in the tree is usually too low toinduce noticeable injury symptoms.Moreover, infestation of large trees oftenbegins in the upper crown and may notreach ground level until the second or thirdyear.One study found the majority of EAB larvaeand emergence holes in recently infestedtrees were more than 15 ft. above groundand almost none were below 6 ft.Therefore, clues of early infestation may notbe apparent to ground-based monitorsunless woodpecker foraging is evident.If infestation is suspected, an arborist mayneed to inspect the tree closer by climbingor aerial lift.© Mark Whitmore, Cornell University

© Mark Whitmore, Cornell UniversityEmerald Ash Borer:MonitoringReviewWhen is monitoring for EAB mostefficient?AnswerWhere does EAB infestation startin trees?Answer

Emerald Ash Borer:MonitoringField Tools for Monitoring EABWhen heading to the field to monitor ashtrees for EAB, there are several tools that canmake the task more accurate and efficient.GPS unit – map the monitoring route and thelocations of infested trees.PDA – document inspection data.Camera – photograph trees or insects forverification of ash species or EAB infestation.ID guides – properly identify ash species,insects, or EAB signs and symptoms.Sampling supplies – collect tree parts inplastic bags and insect specimens in vialscontaining alcohol for submission to adiagnostic lab.Binoculars – inspect upper trunk andbranches for EAB signs/symptoms.

Emerald Ash Borer:MonitoringEAB Signs & SymptomsWhen inspecting vulnerable ash trees, monitors must look for visualindicators of EAB infestation, including the insect, its signs, and itssymptoms. Photos and descriptions of these items are provided inmodule 3 of this course.The most importantthing to rememberabout detection isthat it is very rare thatsigns and symptomsappear on only onetree. If you think yousee an infested treelook at neighboringash to see if theyexhibit similar signsand symptoms.© Steven Katovich, USDA Forest Service,

© Mark Whitmore, Cornell UniversityEmerald Ash Borer:MonitoringEAB Signs & SymptomsIn rural and most suburban areas the easiest way to detect EAB is to lookfor woodpecker foraging on the trunk. Fresh woodpecker foraging beginsto appear in fall and will increase through the winter. Look for the brownishcolor of fresh flaking dispersed around the trunk like a checkerboard ANDthe places where woodpeckers have extricated an EAB.

Emerald Ash Borer:MonitoringEAB Signs & Symptoms (continued)EAB infestation is also commonlydiscovered through detection of othersymptoms on host trees, which include:• canopy thinning• crown dieback• epicormic sproutingUnfortunately, these symptoms are oftensubtle in the first few years of infestationand may be overlooked due to theirsimilarity with other ash pests anddiseases. By the time these symptoms aredetected EAB has been in the area foryears and other trees will be similarlyaffected.© Eric R. Day, Virginia Polytechnic Institute andState University, Bugwood.orgSymptoms may also be erroneously attributed to tree decline caused byinjury, poor soil, extreme weather, or old age. In these cases there areusually only one or two trees affected in the area. In these circumstancesthere will not be the pattern of woodpecker foraging described earlier.

Emerald Ash Borer:MonitoringEAB Signs & Symptoms (continued)Besides the insect itself, the only external signs of EAB are its 1/8” D-shaped emergence hole through the bark surface of trunks andbranches, and its feeding injury on ash foliage. Both of these are difficultto detect at low populations.© Mark Whitmore, Cornell University© Daniel Herms, The Ohio StateUniversity,

Emerald Ash Borer:MonitoringEAB Signs & Symptoms (continued)Vertical bark splitsabove old attacks is asubtle symptom thatcan be easilymistaken for othercauses such asdisease and injury.This symptom is seenonly at lowpopulation levels.© Mark Whitmore, Cornell University

Emerald Ash Borer:MonitoringEAB Signs & Symptoms (continued)The key to detecting subtle EABinfestation symptoms is firstunderstanding the normal,healthy appearance of ashtrees of particular species andage in your community.All vulnerable ash treesharboring insects, signs, orsymptoms similar to EAB warrantfurther inspection. When indoubt, collect a specimen ortake a photograph for properidentification by authorities.© Mark Whitmore, Cornell University

© John Cox, mysuburbanlife.comEmerald Ash Borer:MonitoringReviewWhen monitoring for EAB, whatsymptoms can be seenanytime of year?Answer

Emerald Ash Borer:MonitoringVisual Inspection SummaryMonitoring trees during the growingseason is more efficient because it iseasier to identify host trees, see crowndieback and this is when the adultbeetle is active.While EAB can attack any trees in theFraxinus genus, they prefer trees growingin the open and stressed trees.EAB infestation starts at the top of thetree, which makes it very difficult todetect during initial infection stages.© Eric R. Day, Virginia PolytechnicInstitute and State University,Bugwood.orgSigns and symptoms of EAB infestation include: woodpecker foraging,canopy thinning, crown dieback, epicormic sprouting, D-shaped holes inbark, adult feeding on leaves, and vertical splits in the bark.

© Mark Whitmore, Cornell UniversityEmerald Ash Borer:MonitoringAdvanced Monitoring TechniquesFederal and state agencieshave developed advancedmonitoring techniques toenhance their EAB detectionabilities. These techniques areusually employed incoordinated surveys organizedby resource professionals. Thesetechniques include:Destructive Sampling – ash treeslocated in high risk areas and/orsuspected to be infested by EABare inspected by stripping their bark to look for EAB larvae and larvalgalleries. Although this method can detect a local infestation in its earlystages, it is resource intensive and destroys the sampled tree. Destructivesampling of public trees should only be performed under the supervisionof local authorities

© Mark Whitmore, Cornell UniversityEmerald Ash Borer:MonitoringAdvanced Monitoring Techniques (continued)Girdled Trap Trees for Detection –healthy ash trees are systematicallyselected across a geographical areaand wounded to induce stress, makingthe tree attractive to nearby beetles.A band of bark and phloem is removedfrom the tree in fall, winter, or spring,and then destructively inspected forEAB larvae and larval galleries thefollowing fall.To follow EAB during the flight seasontraps such as the Purple Panel Trap canbe hung in these girdled trees andmonitored regularly.

© Philip Careless, University of Guelph, www.cerceris.infoEmerald Ash Borer:MonitoringAdvanced Monitoring Techniques (continued)Traps – purple panel traps (PPT) havebeen used extensively in the U.S. inrecent years for early detection of EAB.Adult beetles are attracted to the traps’color and chemical lure that mimics thescent of a stressed ash tree.Traps are coated with adhesive tocapture attracted beetles and arehung 12 – 15 ft off the ground in or nearash trees.Traps are distributed in early summer,inspected periodically through thesummer and then collected for finalinspection in fall.

© Philip Careless, University of Guelph, www.cerceris.infoEmerald Ash Borer:MonitoringAdvanced Monitoring Techniques (continued)Biosurveillance – recent researchsuggests that the predatory waspCerceris fumipennis has the potential todetect low levels of EAB.The wasp captures only Buprestidbeetles, including EAB, and stockpilesthem in ground nests. They prefer hardpacked sandy soils like those in picnicareas and baseball fields.Volunteers can locate nests andobserve for the presence of EABbrought their by local wasps. Thistechnique is perhaps the best methodof early detection for EAB.

Emerald Ash Borer:MonitoringDocumenting & Reporting a Suspected EAB infestationThere are severe consequences of EABoutbreak to the community, and allsuspected infestations should be takenseriously and reported promptly to authorities.If you suspect that you have discovered anEAB insect or an infested ash tree:1. Document your locationIf you are in an urban area, note the neareststreet address or intersection.If you are in a forest, mark the tree with aribbon, paint, or hatchet blaze.GPS or map coordinates will help withrelocation.

© Mark Whitmore, Cornell UniversityEmerald Ash Borer:MonitoringDocumenting & Reporting a Suspected EAB infestation2. Collect a sample or photographof the insect or symptomatictree part. Place tree parts in asealable plastic bag. Placeinsects in a bottle or vialcontaining alcohol. Refrigeratesamples until submissioninstructions are obtained.If you are interested in learningmore about collecting samples,review the NPDN module “QualitySample Submission”.NPDN First Detector modules canbe found at

Emerald Ash Borer:MonitoringDocumenting & Reporting a Suspected EAB infestation3. Report your discovery to local, state, or federal authorities. CountyCornell Cooperative Extension and NYSDEC offices will answer yourquestions and forward photos to appropriate authorities. If yourcommunity has an EAB Task Force, urban forester or horticulturist, thencontact that individual. Go to for resources andthe appropriate telephone numbers to call.

Emerald Ash Borer:MonitoringReviewWhat are four advanced monitoring techniques for EAB?AnswerWhat are the steps you should take to document and report a suspectedEAB infestation?Answer

Emerald Ash Borer:MonitoringModule Summary• Monitoring= inspection of vulnerable trees to detect and documentpest activityWhat: all ash tree species, especially stressed and/or trees growing inopen sunny locationsWhen: during the growing seasonWhere: infestation starts in the upper crown and moves its way downthe tree• Look for signs and symptoms discussed in module 3 and reviewed inthis module.• Advanced monitoring techniques include destructive sampling,detection trees, traps and biosurveillance.• If EAB is found, document your location, collect a sample orphotograph, and report your discovery

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