UCCE Tulare County, 4437B South Laspina St. Tulare, CA 93274 Phone (559) 684-3300 • Fax (559) 685-3319

http://cetulare.ucanr.edu

TOPICSINTHISISSUE:

• Real-TimeSensorforEarlyDetectionofCitrusHuanglongbing(HLB)

• The2016InternationalCitrusConference

• UCRiversideScientistsEvaluateTrunkInjectionsofPesticidesforTheManagementofAmbrosiaBeetlesinCaliforniaAvocados

• AnOverviewofMango

• WaterBasedLatexPaintasaMeanstoTrackAmbrosiaBeetleActivityonInfestedTrees

*SubscribeandReadtheWeeklyTopicsinSubtropicsBlogat:http://ucanr.edu/blogs/Topics/

AUTHORSAlireza Pourreza, Kearney Research and Extension Center,UniversityofCaliforniaCooperativeExtension.

BenFaber,UCCEFarmAdvisorinVenturaandSantaBarbaraCounties

FrankByrne,AkifEskalen,JosephMorse.UnivesityofCalifornia

MichaelPiña,MiltMcGiffen,andPhilippeRolshausen,DepartmentofBotanyandPlantSciences,UCRiverside

JosephCarrillo,JohnKabashima,AkifEskalen.DepartmentofPlantPathologyandMicrobiology,UCRiverside,UCCEFarmAdvisorOrangeCounty.

AkifEskalen,Editor

Volume 14 No. 4 November 2016 FARM ADVISORS AND SPECIALISTS Mary Bianchi – Horticulture, San Luis Obispo Phone: (805) 781-5949 Email: mlbianchi@ucdavis.edu Website: http://cesanluisobispo.ucdavis.edu Greg Douhan – Area Citrus Advisor, Tulare, Fresno, Madera Phone: 559-684-3312 Email: gdouhan@ucanr.edu Website: http://cetulare.ucanr.edu Akif Eskalen – Subtropical Extension Pathologist UC Riverside Phone: (951) 827-3499 Email: akif.eskalen@ucr.edu Website: http://facultydirectory.ucr.edu Ben Faber – Subtropical Horticulture, Ventura/Santa Barbara Phone: (805) 645-1462 Email: bafaber@ucdavis.edu Website: http://ceventura.ucdavis.edu Elizabeth Fichtner – Orchard Systems, Tulare Phone: (559) 684-3310 Email: ejfichtner@ucanr.edu Website: http://cetulare.ucanr.edu Craig Kallsen – Subtropical Horticulture & Pistachio, Kern Phone: (661) 868-6221 Email: cekallsen@ucdavis.edu Website: http://cekern.ucdavis.edu Philippe Rolshausen – Extension Specialist Subtropical Crops, UCR Phone: (951) 827-6988 Email: philippe.rolshausen@ucr.edu Website: http://ucanr.edu/sites/Rolshausen/ Sonia Rios – Subtropical Horticulture, Riverside/San Diego Phone: (951) 683-8718 Email: sirios@ucanr.edu Website: http://cesandiego.ucanr.edu Eta Takele – Area Ag Economics Advisor Phone: (951) 683-6491 ext 243 Email: ettakele@ucdavis.edu Website: http://ceriverside.ucdavis.edu

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R E A L - T IM E S E N S O R F O R E A R L Y D E T E C T I O N O F

C I T R U S H U ANG LONG B I N G ( H L B )

Alireza Pourreza, Kearney Research andExtension Center, University of CaliforniaCooperativeExtension.

Californiaisthemajorproduceroffreshmarketcitrus in the U.S., a $2 billion industry that isthreatenedbyadevastatingdiseasecalledcitrusHuanglongbing(HLB).Unfortunately,thereisnocureforthisdiseaseandifatreegetsinfected,itwilldie ina fewyears. InFlorida,HLBwas firstseen in 2005, but after a few years the entirestateofFloridagot infected.Today,about60%ofFloridacitrushasgone,mostlybecausetherewas no efficient HLB monitoring practice. HLBdiagnosis using laboratory-based methodsrequiredmanual sampling and theywere timeand effort consuming. An efficient HLBmanagementrequireshighspatialandtemporalresolution monitoring and eradication ofinfected trees. Therefore, a diagnosis sensor isneeded for detecting HLB infected canopiesbeforethedevelopmentofsymptoms.Forhighresolutionmonitoring,thesensorshouldalsobeabletoconductrapidandinexpensiveinspectionwithhighaccuracy.

Starch accumulation in HLB infectedleavesisanearlyindicationofthedisease.Starchhas an optical characteristic of rotating thepolarization plane of light. We employed thischaracteristic of starch to develop an earlydetection methodology in which the sensingsystem was very sensitive to the rotation inpolarization plane of light. The sensor has acustomized illumination system including 10

high-power and narrow band LEDs at 591 nmand a polarizing film. The sensor also has amonochrome camera equipped with a linearpolarizing filter that is set in a perpendiculardirectiontothepolarizingfilmoftheilluminationsystem.

Theearlydetectionsensorprototype

Starch accumulation in an HLB infected leafgenerates blotchy mottle in an asymmetricalyellowingpattern.DeficiencyofcertainnutrientssuchasMgandZncausessymptomssimilar toHLB.

LeafsymptomofHLB,andZndeficiency

The sensor was mounted on a gatorvehicle and was tested in a citrus grove inFlorida. The polarized images acquired fromhealthy, HLB, and Zn deficient canopies werefurtheranalyzedfordiagnosispurpose.

HLBHealthy ZnDeficient HLB&ZnDeficient

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Polarized imaged from healthy, HLB, and HLBwithZndeficiency

HLB samples were accurately identified fromhealthy and Zn deficient samples. Also, thesensorwasabletodetectHLBwithinZndeficientsamples.

Four classes of samples scatter-plotted basedon image brightness (gray values’ mean) andcontrast(grayvalues’standarddeviation)

The polarized imaging methodology wasadopted in two separate studies at theUniversity of Florida to investigate the earliesttimeHLBcanbediagnosedbypolarizedimagingtechniqueafterinfection.Inonestudy,two-yearoldValenciaorangeplantswereinoculatedusingdisk-graftmethod.

A citrus leaf graft-inoculated by a disk tissuefromaHLBinfectedleaf

Time-lapse polarized images of leaves frominoculated citrus plants were acquired on aweekly basis. HLB symptoms (as starch

accumulation) started to become visible in thepolarized images five weeks after inoculation,while the plants were still in asymptomaticstage.

Time-lapse imagesofa leaf fromHLB infectedplantacquiredonaweeklybasisafterinfection

In another study, the polarized imagingmethodology was employed to detect HLB ininsect inoculated citrus seedlings while inasymptomatic stage. Citrus seedlings wereexposed to intensive HLB-positive Asian CitrusPsyllid (ACP) feeding. Polarized images wereacquiredtwotimes;onceafteronemonthafterinoculation and again two months afterinoculation.AswellasHLBdetection,thelevelofinfection was obtained for different leafsamples.Polymerasechain reaction (PCR) testswereconductedtovalidate theHLBstatusandthelevelofinfectionineachleafsample.

ColorandpolarizedimagesofhealthyandHLBinfectedleafsamplesinasymptomaticstagewithdifferentinfectionlevel

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Currently,we focus on improving the accuracyand early detection performance of thepolarized imaging sensor and developing acommercialized product for practical in-fielddiagnosis. This affordable tool can help theCaliforniacitrusgrowerstoprotecttheirgrovesfromHLB.

I would like to express my greatappreciation to Drs. Won Suk Lee, JohnSchueller,RezaEhsani,EdEtxeberria,BillGurley,and Arunava Banerjee at the University ofFlorida(UF).Also,IwouldliketothankDr.EranRaveh at ARO Gilat Research Center, Negev,Israel,forhisassistanceduringthisproject.

THE2016INTERNATIONALCITRUSCONFERENCE

BenFaber,UCCEFarmAdvisorinVenturaandSantaBarbaraCounties

TheInternationalCitrusConferencewasheldatIguazu Falls (Iguassu or Iguaçu depending onwhatcountryorsideof thefallsyouareon) insouthernBrazilfromSeptember18-23.Thefallsare truly amazing and so was the conference.Thisistheworld’slargestwaterfallsystemandin3minutestheequivalentofallthewaterusedinVenturaagricultureinayeartakesadiveontheIguazu River. The amount of information thatflowedintheconferencewasalmostthesame.Therewereabout1,500fromaroundtheworld,growersbutmainlyresearchers.Andtherewerefolks from California there – two growers, aCitrus Research Board representative, ajournalist,aPestControlAdvisor,sixfolksfromUCR and their graduate students and all thespousesassociatedwiththesepeople.

In18separatesessions,frommarketingtopeststo pathosystems (interactions ofplants/arthropods/disease) to genetics to

breeding to biotechnology to cultural practicesto it seemed togoon forever, the informationflowed. The sessions were actually separatedinto topics as well-defined and distinct asBreeding from Scion and Rootstock Varieties.Someof the informationwasacontinuationofstudies from those presented at the Spanishmeetingfouryearsago.Somewastotallynew.Some was like a test balloon without a lot ofsupportingmaterial.Itwassortoflike,itworkedin this situation on this other crop and mightwork incitrus.Someofthepresentationswerebychemical representatives,but thebulkweremadebyresearchersfromvariousinstitutesanduniversities.Itisgoodtohavethechemicalrepstheretogetsomeinsightintotheproductstheyareworkingon.Sotheconferenceisalotofnewideas andnewproducts. Somemaywork andmanywon’t.

Icansaythatthankfullywedonothavealotoftheproblemsthattherestofthecitrusworldhasor at least that we don’t have yet. There areproblemslikeGreasySpotthatarehighhumiditypathology problems, but there are others likeCitrus Longhorn Beetle and Citrus Canker thatcouldbecomeproblemshereinCalifornia.Theyjustaren’thereyet.Thisconferenceandotherslikeit,liketheAmericanSocietyofHorticulturalSciences and the American PsychopathologicalSociety act like early warning exchanges.Problemsaredescribedalongwiththebiologyofthe problem and then people can determinewhetheritmightbelikelyintheirsituation.

Some of the highlights of the meeting for mewere the presentations on various aspects ofHuanglongbingandAsianCitrusPsyllidandtreeinteractions. It turns out that there are somemajor physiological changes that occur in thetree with not just the disease but also the

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infestation by the insect. The tree can put upvariousdefensesandinternal“communications”inresponsetofeedingbytheinsect.Someofthiscanbe“managed”andhowthiscanbedoneisbeing studied. Some scion varieties androotstocksaremoreresponsivethanothersandwill become a basis for building othercommercial selections of citrus. This will bethrough traditional breeding practices andthroughnewenhancedbreedingmethods thatdo not introduce non-Citrus genetics into theresultingtree.Therearecurrentlyanumberofprojectsaroundtheworldlookingatnewbreedsof citrus and these will be tested for theirresistance/tolerance/immunity to HLB. Therearesomeverypromisingtrialgoingon.

Full commercial applicationof these findings isstill years away. If an ideal combination ofrootstock/scion combination came alongtomorrow,itwouldstilltakeyearstogearupforreplacingtheworld’streesintheground.Inthemeantime,theBraziliansandothershaveshownhow to manage the disease on the groundthrough chemical treatments, monitoring,rogueing and replanting with disease-freematerial. There really is a lot of activity andsuccessatfindingnewandfastertechniquesforfinding diseased trees. This is key in keepinginoculum levels low, so that there is reducedlikelihood of disease spread. There is a lot ofgoodreadingandintrospectionintheabstractsfromtheconference.Ifyoureadthem,don’tbeput off by some of the terminology. Some ishighly technical, as only some professions canspeak,butthereisstillalotofinformationthatagrowercangarnerfromareading.

The abstracts can be viewed at:http://www.icc2016.com/images/icc2016/downloads/Abstract_Book_ICC_2016.pdf. Soon thefullpaperswillbeavailableinaProceedings.I’m

notsurewhenthatwillbeavailable,butalsowillbeavailableonline.

UCRIVERSIDESCIENTISTSEVALUATETRUNKINJECTIONSOFPESTICIDESFORTHEMANAGEMENTOFAMBROSIABEETLESINCALIFORNIAAVOCADOS

FrankByrne,AkifEskalenandJosephMorse,UniversityofCalifornia,Riverside

Two closely related Ambrosia beetles(Euwallacea sp.) have been identified incommercial avocado groves in California. Thepolyphagousshotholeborer(PSHB),detectedinLos Angeles, Orange counties and recently inVentura county, and the Kuroshio shot holeborer(KSHB),detectedinSanDiegoandrecentlyin Orange and Santa Barbara counties, aremorphologically indistinguishable, butgenetically distinct. Already widespread in avarietyofreproductivehosttreescommonintheurban landscape (including box elder, willow,severalmaples,oakandsycamorespecies),thebeetlesrepresentasignificantthreattotreesinboth landscapeandagriculturalsettings. Adultfemalesconstructgalleries inthexylemsystemof host trees, where they cultivate symbioticfungi(Fusarium,ParacremoniumandGraphiumspp.) as a food source for their developingyoung. The fungi are taken up by progenyfemales in specialized organs within theirmouthparts, and transported to other siteswithin the same tree, where new colonies areestablished, or to newly colonized hosts. Thegalleriescompromise thestructural integrityofinfested trees, which can represent a serioussafety hazard in urban environments, anddisrupttheflowofwaterandessentialnutrientswithin the xylem. In addition to the physicaldamage, the fungi extract nutrients from thexylem system, further depriving the tree ofnutrientsessential forhealthygrowthand fruitproduction.

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An effective biological control agent is not yetavailabletomanagetheSHBinCalifornia,andsomanagement for nowmust rely on the use ofchemical pesticides. The control of Ambrosiabeetlesandtheirassociatedfungiusing

Fig.1Woodcoresamplingfromavocadousingincrementborer.

chemical pesticides is complicated because oftheir location inside the host trees. Theapplication of insecticides to the externalsurfaces of trees,where the beetlesmust firstalight prior to boring, has the potential to killbeetles by contact activity, and they may alsohave the potential to control emerging youngadultsbeforetheycanre-infestthetrees.

The drawback of surface treatments is thatmultipleapplicationsareoftenrequiredbecauseof the relatively short duration of efficacy. Inaddition, once the beetle burrows inside thetree,surfacetreatmentsarebecomeineffective.Onepossiblesolutiontothisproblemmaybetheuseof systemicpesticides,andscientistsatUCRiversideareevaluatingtheuseofbothsystemicinsecticidesandfungicidesina2-prongedattackagainstthesymbioticsystem.

Fig.1 Wood core sampling from avocado usingincrementborer.

Systemicpesticidesaremobilewithinthexylemsystem of plants, and the fungicides couldpotentiallytargetthefungigrowinginthexylemanddeprivethebeetle larvaeofafoodsource.Theinsecticideswouldpreventthebeetlefromestablishing galleries within susceptible treehosts, and prevent the survival of beetles andtheiroffspringalreadypresentwithintrees.Thebig problemwith systemic pesticides is gettingsufficient concentrations of chemicals to theareas within the trees where the beetle andfungus occur. Although there are exceptions,most systemic treatments are administered tothesoilforuptakethroughtheroots.However,in mature avocado groves, the high organicmattercontentofthesoilcanpreventeffectiveabsorption by roots because the pesticidebecomes bound to organic componentswithinthe soil. Trunk injection of pesticides directlyintothevascularsystemoftreeseliminatesthe

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potentialforbindingofpesticideswithinthesoil,and increases the amount of active ingredientinside the tree available to impact thebeetle/fungalsystem.Systemicpesticidesmustbeformulatedfortrunkinjectionandsocarefulevaluationisneededtoensureoptimalefficacy.Trialsarebeingconductedwiththeassistanceofavocado industry and grower collaborators inareaswhere the SHB has been recorded. Thechemicals are injected into the trees usingcommercially available equipment, and themovement of the active ingredients is thenmonitored over time in wood core samplestaken at different heights of the trees. Twomethodsarebeingusedtoconfirmthepresenceof the chemicals. Insecticides are beingquantifiedusingELISAsthatarespecific fortheactive ingredients under investigation. Woodcores taken from trees treatedwith fungicidesare placed in direct proximity to the fungalpathogensgrowingonagarplatestodetermineifgrowthofthefungusisinhibited.

Theinvestigationsarestillatanearlystage,butthe researchers are optimistic that they willdevelopeffectivecontrolstrategiesfortheSHBthat growers can incorporate into their overallpestmanagementprograms.Laboratorybasedbioassays have been used to identify severalpesticidesthataretoxictothebeetleandfungi.Theobjectiveof the field trials is todeterminewhetherthesechemicalscanbeutilizedastrunkinjection agents for the protection of avocadotrees. Anyone interested in finding out moreabout the SHB should go to the web sitemaintainedbyDr.AkifEskalenat:

http://eskalenlab.ucr.edu/avocado.html

ANOVERVIEWOFMANGO

MichaelPiña,MiltMcGiffen,andPhilippeRolshausen

DepartmentofBotanyandPlantSciences,UniversityofCalifornia,Riverside.

Mango (Mangifera indica) is amajor fruit treecropofthetropicsandsubtropics,particularlyinAsia,where it is among themosteconomicallyimportantcropsandconsideredbymanytobethe“kingoffruits”.Mangocurrentlyranks5thinglobal production of major fruit crops afterBananas,Citrus,Grapes,andApples.Mangohasvery limited production in temperateMediterranean climates and currently the onlyUS states producing the fruit are California,Florida,andHawaii. InCalifornia,mangogrowsin a geographical range similar to avocado,includingthesoutherncoastalpartofthestate.However, unlike avocado, commercialproductionofmango in theCoachelladesert ispossible(Figure1)despiteseveralchallenges.

Production of mangos continues to growglobally,from21Mtonsin1994to43Mtonsin2013.Much of this production occurs in India,whichaloneaccounts for about30%ofmangoproductionworldwide.Othermajorproducersofmangoinclude(inrankedorder)China,Thailand,Mexico, Indonesia, Pakistan, and Brazil(FAOSTAT 2013 data). Mangoes are a vitalcomponent of the diet in many of the lessdeveloped countries in the tropics andsubtropics.Mostmangoes are eaten fresh andonly about 1% of fruit produced globally isdestinedforprocessing.Generally,thereislittlewastewithmangoproductionas theseedsareused for starch, peels used as a source foranacardic acid, andwood used for low qualitylumber.

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Figure1:MangocanbegrownintheCaliforniadesert.

The mango’s origin is believed to be in thetropicalrainforestsofSouthandSouth-EastAsia.The tree is a tropical evergreen, with simple,alternate leaves ranging from 12-38 cm. Leafshape is highly variable depending on thecultivarandareproducedinwhorls.Fullymaturetreescan reachheightsof40mandsurvive forhundredsofyears.Typically,thejuvenileperiodlastsfrom3-7years.Therootsystemconsistsofalargecentraltaprootandmanyshallowfeederroots.Mango flowers are produced onwidely-branched panicles that reach up to 30cm inlength.Theinflorescenceisverydense,coveredwithhundredsofsmall flowersabout5-10mmin diameter. Flowers are largely fly pollinated,but may also be pollinated by other insectsand/orbywind.

Mangofruitsarelarge,fleshydrupescontainingcarbohydrates,proteins,minerals,vitamins,andamino,organic,andfattyacids.Whileripening,mangosareveryacidicandcontainhighlevelsofvitaminC. Fully ripemangos containmoderatelevelsofvitaminCandarerich inprovitaminAand vitamins B1 and B2. Sucrose is the primarysugaroffullyripenedmangosandaripemangocontainsabout11%-20%sucrose,or15%-20%ofthetotalsolublesolids.

Figure2:Evaluationofcovercrops(left:sudangrass–right: alfalfa) in a California desert mangoproductiontoimprovesoilfertilityandmitigatetreenutrientunbalance.

While annual cereal and legume cropsbenefitted greatly from the agronomicimprovements of the Green Revolution, theimprovement of tree crops has lagged behind.Thisisduetotheircomplexgenetics(polyploidy,heterogeneity),longlifecycles,andhighcostofmaintenance.Although treecrop improvementtechnology is progressing rapidly, most fruitcultivars today tend to come from ancientselections. Thus,mango trees continue to faceserious problems including alternate bearing,frostintolerance,lackofdiseaseresistance,andlowyields.

The desert of Southern California’s CoachellaValley presents a unique set of challenges for

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mango production, especially in an organiccertified orchard. The alkaline (pH 8.1)calcareous sandy loam soil can cause treenutrient unbalance. High day temperatures inthe summer (115°+F) cause high nutrientturnover and leaf/fruit burn while low nighttemperatures in the winter (29°F) can causeirreversible frost damage. To address thesechallenges, our research group atUCRiversidehas been working since 2014 towards using acombinationofacidified irrigationwater, covercrops (Figure 2), and soil amendments toenhancethesoilfertilityandultimatelyimprovemangoyieldsinthisorganicsystem.

WATER-BASEDLATEXPAINTASAMEANSTOTRACKAMBROSIABEETLEACTIVITYONINFESTEDTREES

JosephCarrillo1,JohnKabashima2,AkifEskalen1

1-DepartmentofPlantPathologyandMicrobiology,UCRiverside,2-UCCEFarmAdvisorOrangeCounty,Emeritus.

Ambrosia beetles are known to cultivatetheir symbiotic fungi as a nutrient sourceinside the various woody hosts they boreinto and colonize. In their natural tropicalenvironment,thebeetlesserveanecologicalpurpose by accelerating degradation ofdecayingwood.However,whenintroducedto a non-native environment, the beetlescancausesignificantdamageinlivinghosts(Hulcr and Dunn, 2011). Since 2012, insouthern California, a disease calledFusarium Dieback has been causingsignificant damage to landscape trees,native tree species, and agriculturallyimportantcrops,suchasavocado(Eskalenetal.,2013).Thisdiseaseistheresultofactivityfrom two closely related invasive ambrosiabeetles and their associated mutualisticfungi.ThesetwoShot-HoleBorers(SHB)are

morphologically indistinguishable,buthavebeen found tobegeneticallydistinct alongwith the fungal symbionts they cultivate.Currentlythereare limitedoptionstotreataffected trees which too often result incompleteremovalofinfestedtrees.

Figure2:Showsafemaleshot-holeborerblockingtheentryholewithherabdomen(A)andincrosssection(B).

To establish inside a host, a single femalebeetle bores through the bark to initiategalleryconstructioninthewood.Soonafterthe initial attack, the female beetleinoculates the wall of the galleries withfungal spores of their associated symbioticfungi (Fusarium spp., Graphium spp.,Paracremonium pembeum) which they useasafoodsource(Lynchetal.,2016,Freemanetal.,2015).Afterthefemalehascompletedconstructingandinoculatingthegallery,andlaying eggs, the female beetles wereobserved blocking the entry point of thegallerywiththeirabdomen.Iftheentryholeis obstructed by a foreign object, then thebeetles will clear the entrance of theobstructionandcontinuetoblocktheentrypoint of the gallery with their abdomenwhich indicates that thebeetle isaliveandactive. However, upon close inspection ofindividual entry holes, it is apparent thatbeetlesarenotpresentoractiveinallentryholes inspected. In this study, we tookadvantage of the blocking behavior of thebeetletodetermineifgalleriesareactiveinordertodeterminetheefficacyofpesticides

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applied to affected trees in an attempt tomanagethispest.

Figure 3: A-D shows the process of counting theinitial area for beetle attacks (A), applying water-based latex paint with brush (B), All the holescoveredbythepaint

We are currently testing various pesticidesalongwithevaluationmethodstoaccuratelyassess the efficacy of applied treatments,with the ultimate goal of managing thesepests and their symbiotic fungi. Whenconducting field trials to investigatepesticideefficacyonreducingSHBactivity,itcanbedifficulttodeterminewhichgalleriesare active or inactive. Close inspection canhelpdetermineifagivenentryholeisactive,but in heavily infested trees there can beover100entryholesto inspect inasquarefoot, which can be time consuming andincrease the possibility of miscounting. Toeasily distinguish between whether thebeetleisaliveordeadinthegallery,wehavedeveloped a method using water-basedlatexpainttocoveradesignatedareaonaninfestedtreeandcompareactivitybetween

areaswithinthesametreeandalsobetweendifferent trees. This method is particularlyusefultocomparepesticidetreatmentsfromone treated tree to another in order toquantify the efficacy of experimentaltreatmentsonSHBactivity.

Figure 4: Progression of beetle reemergence afterpaintapplication.Afterpaintapplicationhasbeguntodry (A), the female beetlewill begin to re-establishtheentrypointwithherabdomen(B),breakthroughthe paint obstruction (C), and continue tomaintainthegallery(D).

Figure1:CountsofSHBattacksoveraone-monthperiodtreatedwithvariousappliedchemicalsafterapplicationofwater-basedlatexpaint.

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Themethodwas as follows: An 8” x 11.5”(sizeofanA4papersheet)areawasoutlinedinverticalorientationwithapaintmarkerateach cardinal direction, on the trunk, at aconsistent height, for a total of fourreplications on each tree per treatment.Beforepaintingthemarkedarea,entryholeswerecounted.Afterinitialcounting,theoff-whitewater based latex paintwas appliedwithapaintbrush.Thepaintedareaswererevisitedandcountedagainthenextdaytolook for visible entry holes; the areas thathaveholesvisibleafterthepaintapplicationhasdriedareindicativeofactiveentryholes(Figure 2D). These painted areas wererevisited the following month to track theactivity. If newentry holeswere visible onthe painted area, this indicates an activebeetle gallery. In our trial, we comparedthree chemical treatments toanuntreatedcontroltoobserveeffectsonbeetleactivity.InFigure1,thereisasignificantdecreaseinSHB attacks from “Before Paint” to “DayAfterPaint”sinceallholescounted initiallyarenottrulyactive.TreatmentsBandCwereshowntohaveastatisticallysignificantlowerincrease in active entry holes within amonth’stimewhencomparedtotreatmentAandtheuntreatedcontrol.Thismethodisa useful evaluation method to monitorbeetle activity as a response over time toappliedtreatmentsinfieldtrials.

References:

1. Eskalen,A*.,Stouthamer,R.,Lynch,S.C.,Rugman-Jones,P.,Twizeyimana,M.,Gonzalez,A.,Thibault,T.2013.HostRangeofFusariumDiebackanditsAmbrosiaBeetle(Coleoptera:Scolytinae)VectorinSouthernCalifornia.PlantDisease.In97:7,938-951

2. Freeman,S.,Sharon,M.,Dori-Bachash,M.,Maymon,M.,Belausov,E.,Maoz,Y.,...&Mendel,Z.(2016).SymbioticassociationofthreefungalspeciesthroughoutthelifecycleoftheambrosiabeetleEuwallaceanr.fornicatus.Symbiosis,68(1-3),115-128.

3. Hulcr,Jiri,andRobertR.Dunn."Thesudden

emergenceofpathogenicityininsect–fungussymbiosesthreatensnaiveforestecosystems."ProceedingsoftheRoyalSocietyofLondonB:BiologicalSciences278.1720(2011):2866-2873.

4. Lynch,S.C.,Twizeyimana,M.,Mayorquin,J.,Wang,D.,Na,F.,Kayim,M.,Kasson,M.,Thu,P.Q.,Bateman,C.,Rugman-Jones,P.,Hucr,J.,Stouthamer,R.,Eskalen,A*.2016.Identification,pathogenicity,andabundanceofParacremoniumpembeumsp.nov.andGraphiumeuwallaceaesp.nov.-twonewlydiscoveredmycangialassociatesofthepolyphagousshotholeborer(Euwallaceasp.)inCalifornia.Mycologia,108(2),pp.313-329

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