TheTurfisOnFire

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TheTurfisOnFire

Weather

ThisJunehasbeenadoozy,withnow18straightdayswithabove90degreehightemperaturesinColumbia.Currently,mostofMissouriis4–6degreesabovenormalnow,withtherecordbooksbeinginsightforthemonth.EvenwiththecooldownexpectedcomingTuesdayintoearlyJuly(seebelow),averagetemperaturesareexpectedtonearoreclipsethoseof1953,possiblymakingitthethirdorfourthwarmestJuneonrecord.Alongwiththeheat,apersistentdroughtpatternhasremainedovermuchofMissouri.Welcomerainsoverthemiddleportionofthestatedropped0.5–1inchofprecipitationearlylastweekwithlocallyhigheramountsinthenorthwestandsouthwestMissouri.AnicedouseofrainyesterdayalsoprovidedmidMissouriwith0.25–0.5”ofadditionalprecipitation.Overthelast30days,however,theI-70corridorfromSt.Louis-KCandmostofcentralMissourihavesufferedintensedroughtwith2–4”precipitationdeficitsoverthetimeframe.Asstatedinthepreviousupdate,thisisaccompaniedbyhighevapotranspirationratesofover0.25inchesonmostdaysforatotalofover5inchesofETlostforthemonth.Theforecastdoesn’tcallformuchrelief,andasoftenisthecaseadroughtpatternisexpectedtoperpetuateadroughtpattern.ThedroughtmonitorstillhasmuchofcentralandnortheastMissouri(ColumbiaintoSt.Louis)listedasabnormallydry.

TheTurfisOnFire

QuickHits:• BrownPatch/PythiumonTallFescue:Asindicatedinthelastupdate,ifatallfescue

lawnisirrigatedandintheshade,itisextremelypronetobrownpatchthistimeofyear.Wehaveconsiderablylargeoutbreaksofbrownpatchattheturffarmnow,andwiththeheatandhightemperaturessomePythiummayalsobeontheprowl.Azoxystrobin(Heritage)canbeconsideredfordiseasecontrolnowsinceitprovidesexcellentcontrolofbrownpatchandsomepreventivecontrolofPythium.

TheTurfisOnFire

• ChinchbugsonZoysiagrass:Areportcameinlastweekofasevereoutbreakofchinchbugsonhiszoysiagrasslawn.Thesustainedheathasspurredtheiractivityandsubsequentdamage,whichcanmirrordroughtsymptoms.Donotmistakethisdamageforlargepatch,whichisoveranddoneatthistimeofyear.Chinchbugsalsopreferfullsun,andmostdamageonzoysiawillstopatshadelines.Curativecontrolwithapyrethroidorothercontactinsecticideisrecommended,buttakecaretoapplywithreductionofnon-targeteffectsinmind.Scoutingforchinchbugsismosteffectivealongsidewalksanddrivewayssincetheyaresmall(sizeofFDR’snoseonthedime)andtheadultsaredarkcolored.Youmayalsocutachunkofturffromtheoutsidemarginofasuspectedareaandputitinasealedplasticbagonahotsidewalk.Ifpresentthechinchbugswilltrytogetoutoftheplasticsaunaandareeasilynoticed.

• DoubleRootWhammy:AsamplewassubmittedinmidJunefromtheKansasCityareathatwasafirstforme.TherootswereclearlyinfestedwithPythiumspp.causingrootrotwhilethesamesamplewasalsosufferingfromhydrophobicsoilsandlocalizeddryspotasevidencedwithawaterdroplettest.It’simportanttorecallrecentweatherKChistoryandthestandsymptoms(shownabove)tounderstandhowthismayhaveoccurred.MaywasparticularlywetinKansasCityandsoilsweresaturatedattheinfectionperiodwhenPythiumrootrotwouldberolling.OnlysinceJunehasKansasCitybeenafflictedwiththis“flashdrought”.SymptomsweretheresultofadoublewhammyofpreviousPythiuminfectionwhenwettocompromisetheroots,andthequickpopoflocalizeddryspot,whichisbroughtonbyquickwet/drycycles.ThesuperintendentappliedKoban/Terrazoleasanopeningjab,followedwithawettingagentandventing,andthenclosedwithaSegway+QoIfungicidecombination.

TheTurfisOnFire

• Fairyringonputtinggreens:Fairyringhasbeenreportedatseveralsitesinthe

region,andisveryprevalentnowonsomeofourresearchgreensattheturffarm.Thediseaseisveryprominentonayoungergreenthatwasbuiltin2012,withpuffballsbeingproducedonitandseveralothergreens.Fairyringswilloftenfirstinvadethesand-basedprofilefromtheoutsidecollarin,asshownintheabovepicture.Atthispoint,theDMIswillnotbeeffectiveincontrollingthedisease,andamulti-prongedapproachofrelievingthesoilhydrophobicityandstoppingthefunguswillneedtobeemployed.Atank-mixofflutolanil(ProStar),azoxystrobin(Heritage),pyraclostrobin(Insignia)alongwithawettingagentisrecommendedforcontrol,alongwithanaggressivesolidorcoreaerificationalongringmarginstoencouragewaterinfiltration.

• Avidpurchaseforuseasnematodecontrolonputtinggreensiscomingtoaclosethisweek.Ashasbeenreportedoverthelastfewweeks,the24(c)SpecialLocalNeedslabelwillbecancelledonJune30,2016sopurchaseswillnolongerbepermissible.SuperintendentshaveanadditionalyearuntilJune30,2017touseexistingproduct,includingtheMultipakthatwasavailableinconjunctionwithHeritageandHeritageActionfungicides.AnewnematicidefromSyngentaisexpectedtoreplaceAvidin2017,alongwithnematodeproductsfromvariousothercompanies,sostaytuned…

TheTurfisOnFire

• AswasobservedprevalentlyinmidJune2014,samplesandreportsofblue-greenalgae

(cyanobacteria)andresultingyellowspotoutbreakshaveoccurredinthelastfewdays.Cyanobacteriacancompetewithotherorganismsbyproducingtoxins,excretingsiderophorestocompeteforiron,orcloggingsoilmacroporesandcreatingablacklayercondition.Theyhavealsobeenimplicatedasthecauseofadiseaseknownasyellowspot,whichinvolvesadistinctchlorosispresumablyresultingfromthetoxin.Culturalpracticestoreducethisproblemrelyondryingdowntheturfsurfaceandmatlayerthroughcarefulirrigation.Additionally,venttiningonaregularbasismaygreatlyaidinthedrydownandalgaereduction.Regularapplicationsofchlorothalonilandmancozebmayaidinalgaereduction.QoIfungicides(Heritage,Insignia,Compass,etc)mayresultinhigherlevelsofyellowspot,soaregularapplicationscheduleofchlorothalonilmaybenecessarytomaintainadequatealgaelevelswhenQoIsareapplied.Foramorecompletesummaryandexplanationofcyanobacteriaeffectsonputtinggreens,clickheretoreadagreatresearcharticlewrittenbyTredway,Stowell,andGelernter.

TheTurf,TheTurf,TheTurfisOnFire

TheTurfisOnFire

Obviously,therestofthesong’schorusreferencedaboveisextremelyinappropriate,butthisparticularlineisverypoignantinpointingoutthecurrentsituationforcoolseasonturfgrassesinMissouri.Manysamplesofdroughtstressedlawns,andevensomesportsturfhavebeensubmittedoverthepasttwoweeks.Someofthepictures,asintheleftpanelshownabove,seemhorrific.Thisarticlewasstartedlatelastweek,andmostofMissourireceivedagoodamountofrain(0.3–0.5)yesterdayforabitofarecharge.Overall,though,midMissouriissomewherearound8-9”belownormalfortheyearthusfar,whichharkensbacktothoughtsofthe2012drought.The2012droughtstartedearlierandwasamuchmorewidespreadphenomenonthanthisyear,spanningmostoftheMidwestandMidsouthregions(seebelow).Dewpointsandhumiditywerealsomuchlowerin2012then2016,whichperpetuatedhigherandsustainedamountsofheatanddroughtstressinplants.StilliflookingatColumbiaweatherdatafromJune1-25alone,temperatureshavebeenhigherin2016than2012(88.1Faveragedailyhighvs.86.4F)andlessrainhasfallen(0.76”vs.1.21”).Themostseverelyimpactedareashadtrafficorwerecontinuallymoweddespitebeingdrought&heatstressed,and/orwerewateredinefficiently.Droughtstressedordormantturfgrassesshouldnotbemowedorexcessivelytrafficked.Footprintingafterwalkingonthelawnoracrunchsoundunderyourfootisnotagoodsign.Mostimportantly,ifit’snotgrowingthereisnoneedinmowing.Non-irrigatedcoolseasonturfgrassesonourresearchfarmhaven’trequiredmowinginthelastthreeweeks.Thepursuitofthecolorgreeninadroughtsituationsuchasthiscanleadtomoreproblems

TheTurfisOnFire

thangood.Tallfescue,andtoamuchlesserextentKentuckybluegrass,hasagooddroughttolerancemechanismthatresultsintheplantgoingdormant.Thisdormancyappearsasanevenlightbrowntotanappearanceindormanttallfescue,andintoughtoirrigateornon-irrigatedareasthisisagoodthing.Wateringinefficiently(pullingahosearoundeveryonceinawhile)doesn’tallowtheplanttogointodormancyefficientlyandkeepsitteeteringbackandforthinaweakenedstate,makingitsusceptibletodisease,heat,andtrafficstress.Inaddition,manyhomeownerswaterintheevening,whichmaybeconvenient,butcanspurdiseaseoutbreakssuchasbrownpatchandPythium.In2012,dormanttallfescuecamebackjustfinethenextfallwhentherainsreturnedafter7straightweekswithoutadropofprecipitation.The5”ofshortcropevapotranspirationlostfromJune1-23equatestoover135,000gallonsofwaterperacre,oronanormallawnof0.2acresabout27,154gallons.Fortherecommended70%replacement,ahomeownerwouldhavehadtoapplyover19,000gallonsofwaterthismonthalonetokeepupwiththedeficit.ThosepullinghosesaroundonlawnsthroughoutJunehavehadlittlechancetoeffectivelyputoutthismuchwaterandkeepcoolseasonturfgrassesoutofdormancy.Atsomepointearlyinasummerdrought,thosethatcan’twaterwellshouldn’twateratall,andshouldstopkillingtheirlawnwiththekindness.

LeeMillerFollowonTwitter!@muturfpathLikeonFacebook!MizzouTurfgrassExtensionTurfgrassPathologist-UniversityofMissouri