Fusarium Dieback in California: another ambrosia beetle associated disease of avocado and urban forest

A.Eskalen1, S.C.Lynch1,F.Na,J.S.Mayorquin1,J.D.Carrillo1,A.Lira2,T.Atkinson3

1DepartmentofPlantPathologyandMicrobiology,UniversityofCalifornia,Riverside,CA925212Ecologyandevolutionarybiology,Inecol,Mexico

3EcologyofambrosiabeetlesfromUniversityofTexas

AvocadoLaurelWiltSummit,Homestead,FloridaNov3-4,2016

Outline• Overview• CurrentreproductivehostsofSHB• CurrentsituationonavocadoinCalifornia• CurrentsituationonurbanforestinCalifornia• Controlstrategiesandbestmanagementpracticesonavocado

LosAngelesCoOrangeCo

SanBernardinoCoRiversideCoVenturaCo.

PolyphagousShotHoleBorerPSHB

Euwallacea sp.

KuroshioShotHoleBorerKSHB

Euwallacea sp.SanDiegoCoOrangeCo

SantaBarbaraCoSanLuisObispoCo

Graphiumeuwallaceae

Paracremoniumpembeum

Fusariumeuwallaceae(Freemanetal.2013) (Lynchetal.2015 (Lynchetal.2015)

Fusarium sp. Graphium sp.(Newspecies) (Newspecies)

A.Eskalen

Polyphagous and Kuroshio Shot Hole Borersand their symbiotic fungi

Koch’s Postulates – Pathogenicity test

MeanlesionlengthsonavocadoandboxeldershootsinoculatedwithisolatesofFusarium euwallaceae, Graphiumeuwallaceae andParacremonium pembeum.VerticallinesrepresentstandarderrorofthemeanaccordingtoFisherprotectedLeastsignificantdifference(LSD)meanseparationtestatα=0.05.

BB

A

0

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4

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16

Fusarium euwallaceae Graphium euwallaceae Acremonium sp. Control

Lesi

on L

engt

h (c

m)

Persea americana Acer negundo

C

Paracremonium pembeumGraphium euwallaceae

Avocado BoxElder

• Lynch and Eskalen , 2016. Mycologia, 108(2), pp.313-329

Growth rate of symbiotic fungi in different temperature

Fungaldiameter(cm)

Temperature°C

12345678910

5 10 15 20 25 30 35 40

Paracremonium pembeum

Graphium euwallaceae

0

Fusarium euwallaceae

Fusarium dieback and symbiotic fungal pathogens

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Number of reproductive hosts that beetle/fungus can produce their offsprings

1. Boxelder(Acernegundo)*2. Californiasycamore(Platanusracemosa)*3. Londonplane(Platanus xacerfolia)4. Redwillow(Salixlaevigata)*5. Blackwillow(Salixgooddingii)*6. Arroyowillow(Salixlasiolepis)*7. Cottonwood (Populus fremontii)*8. Blackpoplar(Populus nigra)*9. Blackcottonwood(Populus trichocarpa)*10. Mimosa (Albizia julibrissin)11. EnglishOak(Quercusrobur)12. Engelmannoak(Quercusengelmannii)*13. Valleyoak(Quercuslobata)*14. Paloverde(Parkinsoniaaculeata)*15. Bigleafmaple (Acermacrophyllum)*16. Japanesemaple (Acer palmatum)17. Castorbean (Ricinus communis)18. CanyonLiveoak(Quercus chrysolepis)*19.Avocado (Persea americana20.Tridentmaple(Acerbuergerianum)21.Coastliveoak (Quercus agrifolia)22.WhiteAlder (Alnus rhombifolia)*23.Titoki (Alectryon excelsus)24.CorkOak(Quercus suber)

Eskalen andLynch,2016.Unpublisheddata

25.Coraltree (Erythrina corallodendon)26. Bluepalo verde (Cercidium floridum)*27.MoretonBayChestnut (Castanospermum australe)28.Brea(Cercidium sonorae)29.Mesquite(Prosopis articulata)*30.Weepingwillow (Salixbabylonica)31.Chineseholly (Ilex cornuta)32.Camelia (Camelliasemiserrata)33.Acacia(Acacia spp.)34.Liquidambar(Liquidambarstyraciflua)35.RedFloweringGum (Eucalyptusficifolia)36.Japanesewisteria(Wisteriafloribunda)37.Goodding's blackwillow(Salixgooddingii)*38.Treeofheaven(Ailanthusaltissima)39.Kurrajong (Brachychiton populneus)40.Blackmissionfig(Ficus carica)41.Japanesebeech(Faguscrenata)42.Denselogwood(Xylosma congestum)43.MuleFat(Baccharis salicifolia)*44.Carrotwood (Cupaniopsis anacardioides)45.Californiabuckeye(Aesculus californica)*46.MuleFat(Baccharis salicifolia)*47.KentiaPalm(Howea forsteriana)48.KingPalm(Ptychosperma elegans)

ParksBackyardTrees

Urban Forests Impacted

GolfCourses

StreetTrees

MixedEvergreenForests OakWoodlands FoothillWoodlands

Riparian

California Native Plant Communities Impacted

Current Situation onavocado in California

• Totalgrovessurveyed:26• 1ha(2.47acres)monitoringplotestablished• Examinedeverytreewithintheplot• Totaltreessurveyed:4,346x3times

Monitoring infested avocado groves

SHB infestation habit on avocado in California

Branch dieback on Avocado

Sugar exudate and internal symptoms on avocado branch

Beetle attack on branch collar and pruning wounds on avocado

Current Situation in Urban Forest in California

Damage on Landscape trees

Mean(attacks/m^2) vs. TimePark

Carbon Canyon

atta

cks/m

^2

0

50

100

150

200

250

Aug '15Sep Oct Nov

Dec Jan Feb Mar AprMay Jun Jul

Aug '16

Time

Beetle attack incidence on an infested sycamore tree overtime

May2015 Feb2016

Tijuana River Valley Before and After Pictures

Boland,2016

Control Strategies

Laboratory Fungicide Screening Experiment

aaaab

abb

cc

dNoInhibitionNoInhibitionNoInhibitionNoInhibition

0 1 2 3 4 5

Metconazole

Pyraclostrobin

Tebuconazole

Thiabendazole

Propiconazole

Triflumizole

Fluopyram

Mycobutanil

Pyrimethanil

Fluxapyroxad

Trifloxystrobin

Triadimefon

Azoxystrobin

EC50Values(ug/ml)

Treatm

ent

EC50Values

TreeIVinjectionsystem Quick-JetAirinjectionsystem

Field Pesticide Trial on Avocado

This slide is blank on purpose. Please see next slide.

• Iftheinfestationisonthebranchcollar,cutintobranchcollar.

Best Management Practices on Avocado

• SpraypruningwoundwitheitherBifenthrin or2%(Bacillussubtilis).

• Chipinfestedwoodon-sitetoasizeofoneinchorsmaller.• Solarizechippingmaterialusingclearplastictarpforseveralmonths

• CompostchippingmaterialandthenuseasmulchinthegroveIfthebranchistoolargetochip

• Fumigationwithphosphinegas(Arpaia andRios,2015)

• Don'tmoveinfestedplantmaterialwithoutchippingandsolarizing

Best Management Practices on Avocado Cont.

FrederiqueRevenchon,Inecol,MexicoBenFaber,FarmAdvisor,VenturaCounty,CA\RichardDemerjian,UCIrvineSoniaRios,UCCEFarmAdvisor,SanDiegoSabrinaDrill,UCCELAandVenturaDanBerry,HuntingtonBotanicalGarden,GaryBender,UCCE,Emeritus,SanDiegoCo.JanisGonzales,UCCESanDiegoJimFolsom,HuntingtonBotanicalGardenJiriHulcr,Univ.ofFloridaKerryO’Donnell,NCUR-ARS-USDAMaryLuArpaia,UCRiversideKimCorella,CalFireTomSmith,CalFireJoeBarcinas,PCATomRoberts,PCAMathewHand,PCALindaBellamy,VentureSusanFrankel,USDAForestServiceTomAtkinson,UniversityofTexasSeanFeirer,UCANRJimDowner,UCCEVentura

CaliforniaAvocadoCommissionU.S.ForestService,OCParks,UCIrvine,UCANR,USDAFarmBill,Arborjet,Mauget,USDAForestService,Cal-Fire,HuntingtonbotanicalgardenandLAarboretum,UCMexus,Inecol,Mexico.

Collaborators

www.eskalenlab.ucr.edu