DancingFaeries

Weather

AugustinMissouriiscurrently5–7degreesbelownormal,andit’swell…justawesome.ThefirsttendaysofAugusthavefeltlikefall,andcoolseasongrassesarereapingthebenefitsofthisearlybreakfromsummer’sswelter.Daylengthisalsobeginningitsgradualslidefromaheightof14h52minonJune21downto13h48mintoday.Thinkanhour’snotthatbigadeal?Askbentgrasshowmuchitenjoystheextrahouroffperdayfromthebeatingdownofthesun’sheavyglare.Nottomentioninjustalittleoveraweek,they’llalsobeamiddaybreak.Midtoupper80sreturnnextweekforhighs,butatleastit’sanhourlessofthosehighs.Theconsistencyofreducedtemperaturesmaybewelcome,buttheinconsistencyofrainfallintheregionispronounced.Missourihasbeenasplitofthehavetoomuchandthehavetoolittleoverthelast30days.TotheeastinSTL,precipitationisaninchbelownormalalreadyforAugustafterbeingbelownormalinJulyaswell.Non-irrigatedtallfescuelawnsaredormantinmuchoftheeast,andshouldbeleftthatwayuntilrainsreturn.Ontheflipside,istheKansasCityareawhichgotwallopedwithanother5”+rainfalleventagainlastSaturday(seebelow).Ourrainfallchancesdostickaroundthroughmid-August,soeventhoughthetemperaturesaremildit’snottimetoputawaythescoutingeyesordiseasepreventionquiteyet.Asyoucanseebelow,somesoilbornediseasesonputtinggreensarestillworking.

DancingFaeries

QuickHits

• PythiumRootRot–Notsurprisingly,severalbentgrassputtinggreensamplesfrom

KansasCityandSpringfieldhavecomeintothediagnosticlabinthepastweekwithsignificantamountsofPythiumrootrot.Tworaineventsrangingfrom5-7”inatwoweekspanwillshowhowfastthegreensareperking,andhowmuchorganicmatterhasbuiltuptostopit.Pokeholesandusepenetranttypewettingagentstomovethewaterthroughandout.AsubmergedPythiumpathogenisadangerousone,sincesporangiaare“designed”tobecreatedandproducemotilezoosporesquicklyfordissemination.IoftencanseemotilezoosporesmovingandencystingonrootswhenIfloodaslidewith

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watertomountthecoverslip,whichisexactlywhatisoccurringwhenyourrootzoneissaturated.Inacurativesituation,ethazoleoretridiazole(KobanorTerrazole)isrecommendedforaquickknockdown,followedup3-5dayslaterwithaSegway+QoI(i.e.Fame,Insignia,Heritage)applicationformoresustainedpreventivecontrol.TheseapplicationsshouldbewateredintogetthefungicideintothesoilprofileandforKoban/Terrazoletoavoidfoliarphytotoxicity.Atthistimeoftheseason,takestockofyourrootdepth.Aslittleas0.1”maybenecessaryforshortrootzones,whereasmoderatedepthrootzonesmayrequire0.125”.

• Algae:Inseveralinstancesoverthelasttwoweeks,we’vealsonoticedquiteabitofalgae/cyanobacteriagettingalittletoofriskywithbentgrass.ThesesampleshavebeenfromboththeKC/Springfieldwhererainisdoingmuchofthework,andalsoinSTLwhereconstantirrigationhasbeenneeded.Algaeisoftenobservedthistimeofyearasmatalongthesoilsurfaceorinterweavedamongthestolons,butinthesecasesthealgaeiscloselytiedwiththeleaves,andwithinthebaseoftheleafsheath.Presenceherecanbeabituncomfortablesinceweknowsomealgaespeciescanproduceaphytotoxinandyieldchloroticsymptomslikeyellowspot.ParticularlyifyouhavebeenrelyingheavilyontheQoIfungicidesforcontrol,considerrotatingtoachlorothalonil(DaconilUltrex,ZnorAction)tankmixedwithmancozebtoknockthealgaeback.IalsonotedthisbackinearlyJune.

DancingFaeries

• Take-allpatch.Takeallpatchwasalsoconfirmedinasampleearlythisweek.This

pathogenisoftenobservedinroots,andittakesquiteabitofittoleadtoadiagnosisofitbeingtheprimarypathogencausingdecline.Inthiscase,thepathogenwasalsointhecrownoftheplantatthebaseoftheleafsheath,theringsymptoms,thepropensitytohitbentgrassratherthanPoa,allmatchedup.Awateredin,highrateapplicationofaQoIfungicide(i.e.Heritage,Insignia)orQoI+partnerproduct(i.e.Briskway/Lexicon)issuggestedforcontrolsincewearetechnicallyinsummer.Asmallshotofammoniumsulfatemayalsobeincorporatedtospurrecovery.

• GrayLeafSpotonTallFescueWarning:AspointedoutbyDr.JimKernsonTwitterlastweek,weareinthetimeofyearwhenbrownpatchcanyieldtotheheavilysporulating,andmorerapidlyspreadinggrayleafspot.Lookforsmallerspotsymptomsandacharacteristicbuggywhippingofheavilyinfectedleaves.Ihaveseenthediseaseoncrabgrass(whichunfortunatelyisjustacosmeticsymptom),butnotyetontallfescue.Seethispreviouspostformoreinformation.

DancingFaeries

FairyRingsnotsoRosie

WhileSnopesindicatesthe“RingAroundtheRosie”nurseryrhymemaynotinfactrefertotheblackplague,whenfairiesstarttodancetothistuneonputtinggreens,ashesofbentgrasscandefinitelybeinvolved.Withinthelastthree–fourweeks,reportsoffairyringoutbreakshavebeencommonintheregion,evenshowinguponourresearchgreen(finallyinatrial!).TheseoutbreaksseemtocorrespondtoourJulyheatwaveandsomeofthefollowingrains,whichseemtohavespurredthediseasealongSeveralpreviousreportshavefocusedonthisdisease,sothispostwon’treinventthewheel.Fordiagnosis,lookfortheobviousgreenringsymptom,butalsodoabitofdiggingparticularlyalongthemarginofthering.Anintenseoutbreakwillcauseanorangediscolorationofthethatchlayer,andinthiscaseyoucanuseyournosetodetectthemustytent-likeormushroom-likeodorofthebasidiomycetefungus.Atthispointoftheseasonaftersymptomsdevelop,it’simportanttorealizethatnotonlythepathogenneedstobesuppressedbutalsothesoilphysicalpropertiesmayneedtoberemediated.Simplymaskingringswithironornitrogenmaybepossibleinlightinfestations,butfairyringsoftencausedeclineinputtinggreensbyformingahydrophobicorwaterrepellantsoillayer.Thissituationneedstobeattackedontwofronts,withafungicidetankmixedwithawettingagent.TheSDHIandQoIfungicidechemistries(i.e.ProStar,Velista,Lexicon)areeffectiveinreducingsymptoms,butcurativelytheymustbewateredinandtankmixedwithawettingagenttogettothetargetzone.Howmuchtowaterin?Atleast0.125”andpreferably0.25”.Thequestionoftenarisesastowhichwettingagenttopickforthisapplication,andI’munawareofanyresearchthatspecificallylooksatdifferencesamongthemforcontrol.

DancingFaeries

FieldDayWrap-upLastbutnotleast,thankyoutoallthespeakers,vendors,sponsors,andespeciallytheattendeeswhovisiteduslastweekforfieldday.Thegreatparticipation,mildtemperatures,andlightbreezemadeforagreatday.Ifyoucouldn’tattend,orforgottotakehomeabooklet,gotohttp://turf.missouri.edu/research/2017_Field_Day_Booklet.pdftogetatasteofourcurrentresearchactivities.LeeMillerFollowonTwitter!@muturfpathLikeonFacebook!MizzouTurfgrassExtensionTurfgrassPathologist-UniversityofMissouri