PETER COPPIN Email: [email protected] Horticultural Consultant Web: www.petercoppin.com
Coniferdie‐backseemstoberunningrampantagain!AlsoknownasCypresscanker,itiscausedbyaSeiridiumfungus(usuallyS.cardinale),andisoftenaswiftanddeadlydiseasetoarangeofConifers,JunipersandPencilpines.
Thediseaseaffectsthevesselsthatcarryliquidsfromtherootsuptothecanopy,causingasevererestrictionorcessationofsap‐flow.Soaffectedbranchesliterallydieofboththirstandstarvation,andthiscanoccurveryrapidly(adollarforeverytimeI'veheard"itseemedtodieovernight").
InEuropeandpartsoftheU.S.,it'sbelievedthatmostinfectionisspreadbywater‐splash,especiallyduringspringsnowmelts.Whilewater‐splashcanberesponsiblehere,mostinfectionsseemtobecausedbyborers,thoughduringthenineties(andprobablysince)someretailnurserystockwasobservedasbeinginfected.Aswithmanydiseases,stressedtreesaremorelikelytosuccumb(andarealsomoreattractivetopestssuchasborers).Itreallysaddensmethatmanypeoplearetoldthereisnothingyoucandoaboutit,whenexactlytheoppositeistrue.Treatmentwithphosphoricacidischeap,safeandusuallyveryeffectiveiflessthenone‐thirdofthecanopyhasbeenaffected.
Somedotpoints:
• Usuallymostdeathordamageisseeninsummer(whenthereismaximumheatandmoisturestress),butthisseasonI'vewitnessedalotofdamageinlatespringandearlysummer(2011/12).
• Followingonfromthelastpoint,pleaseknow
thatalargernumberofsmallerdeadpatchesinacanopymayactuallybecausedbymites,somakesurethediagnosisisdoneproperlybeforecommencinganytypeoftreatment.
• Onlyinfectedtreesneedtobetreated,and
possiblytheirimmediateneighboursiftreesareplantedingroupsorrows,thoughitissensibletocover‐sprayothertrees(especiallyyoungtrees)onceinthespringwitheitherphosphoricacidorasuitablecoppercompound.
• Youmayreadorbetoldthereisnochemical
treatmentregisteredforthespecifictreatmentofSeiridium.Whiletrueinapedanticway,phosphoricacidandmanycoppercompoundshaveagenericregistrationforuseonornaments,andaren'tconifersornamentals?
• Youmayreadorbetoldthatcontinualdrilling
holesforinjectionweakenstreesandtheycansnapandfalldown.Whatrubbish.Theremayhavebeenaveryslightchancebackwiththedinosaurswhenweusedtodrillanumberof12‐16mmwideholesanduseafunneltopoorininsecticidestotreatborers.Wenowusespecialinjectorsthatonlyneedafew4mmholes.
• Youmayreadorbetoldthatyouhavetotreat
thetreesonceortwiceperyearforever.Totallywrong.Afewtreatmentsoveracoupleofyearsseemstoovercomethediseaseaslongasthetreesarenotbadlystressedfromothercauses.Thenit'samatterofkeepingacloseeyeonthesituationanddofurthertreatmentswhennecessary.
This once would have been a glorious hedge lining the driveway into a semi-rural property in the Swan Valley. Simple, safe and relatively cheap treatments could have saved these trees.
Coniferdie‐back(cont’d)
Ibelieveconifersareanintegralpartofmanyurbanlandscapes,addingadeepergreen,moreformalandattractiveformofevergreentrees.Youcouldsaytheyareoneoftheveryfewnorthernhemispheregroupoftreesgivingusthat'littletasteofEurope'thatmanypeopleseemtowantinmostsouthernstatesofAustralia,nottheleastonthegutlesssandysoilsofPerthandthesouthwestcoastalplain.
Mostspeciestolerateexceptionallyharshclimaticconditionsfromscorchingdrywindsthroughtofrostsandevensnow,andonceestablishedneedlittleornosupplementarywaterings.
Soit’sagreatpitytoseethemdisappearfromourtreescapes.Therearevaryingestimates,butinPerthalonepossibly60%ofsusceptiblespecieshavedied.
Sowhatcanwedoaboutit?Theanswerissomesimpletreatmentscanhaveatleasta90%successrateiflessthanone‐thirdofaparticularspecimen’scanopyhasdiedfromSeiridiuminfection.
Sodon’tlistentothemany‘experts’outtherethattellyouthatit’sawasteoftime–theyeitherhaven’ttreatedtreesproperly,orsomehaven’tevenbeenoutinthefieldandactuallydoneit,andsomesimplywouldn’thaveaclue.
I’vetreatedoradvisedontreatmentsonhundredsofspecimenswithasuccessrateofaround85%,includingthosespecimenswithmuchgreaterthan30%canopydeath.Here’sasummaryofoneofthebestsuccessstoriesI’vebeeninvolvedin:
Thisresidentialpropertyhadawalkwayononeboundaryandlessthanidealneighboursontheadjoiningboundary.TheyhadplantedConifersandJunipersonthesefencelinesthateventuallybecamebeautifulborders/barriers.
Unfortunately,Seiridiumtookholdandsomeofthetreesbegantodiebackandtheyweretoldtherewasnothingtheycoulddo.TheycontactedmesoIvisitedthemandinstigatedatreatmentprogram.
AsInormallysuggesttosavecostsfortheclients,Ishowthemhowtodothetreatmentsthemselves.Becausethesespecimenswere,quote“invaluable’,theclientsdidevenmorethanisnormal.Oneofthespecimenshada60%canopymortality,buttheypersevered(seenextphoto).
Thisspecimenwastreatedanumberoftimesinthefirst3‐4years.Onlyonepreventativeinjectionhasbeendonesince.Thisislivingproofthattreatmentcanbeverysuccessful.
Sohowmuchdoyouvalueyourtrees?Thinkabouthowmuchitwouldcosttoreplacethemwithtreesofthesamesize,orhowlongitwouldtaketogetalternativereplacementspeciestothesamesizeandform.Forthecostofavisitfrommeyoucouldsaveahugeamount.
Verysusceptiblespeciesinclude:(Mostofwhatwecall‘Conifers’areCupressusspporChamaecyparisspportheirhybrids,Cupressocyparisspp).Commonnamesinclude:• Montereycypress• SwanesGolden(andotherselections/cultivars)• CastlewellianGold• NaylorsBlue• Lawsoniaselections/cultivars
Othersusceptiblespeciesinclude:• Pencilpine(Thujaoccidentalis)• Westernredcedar(Thujaplicata)• Junipervirginiana• OtherCupressusspecies:C.arazonica,C.glabra,
C.lusitanica,andC.torlosa
Agreatfact‐sheetoninjectingtreescanbefoundathttp://www.dwg.org.au/files/Phosphite%20Injection%20using%20Chemjet%20Syringes1.pdf©PeterCoppin,23/01/2012Canbereprintedaslongastheauthorisacknowledged.
NOTE:IneedtoacknowledgeCharlesAldous‐Ball,anarboriculturalconsultantwhodidamazinggroundworkonSeiridiumduringtheninetiesandfreelyshareditwithme.
Look at it now!
Seven years after treatment started, this magnificent specimen is now in great condition. Even though it lost its apical growing tip (this often can be terminal), it has again become a healthy tree.
