LawnDormancyLooms

SAVETHEDATE:MUTurfgrass&LandscapeFieldDay-August1

Preparationsareinhighgearfortheupcomingfieldday.Asshownabove,weinitiatednewresearchplotstoinvestigatetheinfluenceoffrazemowingandinterseedingofcoolseasonturfgrassondiseaseseverityandqualityofzoysiagrassandbermudagrass.ManythankstoPerfectPlayFieldsandLinksforloaningustheunittoinstallthisresearch,andfortheexpertoperationofDanielEarlywineandDr.BradFresenburg.ThisprojectisthebrainchildofDaniel’s,whowillbediscussingandintroducingthisresearchatfieldday.Ifcuriousaboutthisresearch,(andwhowouldn’tbe!),registerandattendtheMUTurfgrassandLandscapeFieldDay.Registrationisopenandthescheduleisset–http://mufieldday.org.ComeonoutAugust1toourresearchfacilityatSouthFarms,andwe’llgiveyouthelatestonthisresearchandotherregionaltopicsofinterest.Formoreinformation,feelfreetocontactmeatturfpath@missouri.eduorKevinDernatmufieldday@gmail.com.Lookforwardtoseeingyouthere.WeatherSummer’sheatishereinfullforce,andlookstostayforawhile.Hightemperatureshavebreachedthemid90sinthelasttwodayswithheatindices(whichtakeintoaccountthehighhumidity)wellintothe100s.Evapotranspirationratesareinthe0.25-inchrangeoverthelast4days,andwouldbeworsewithoutthisuncomfortablehumidityfromsoutherlyGulfair.Waterisgoingfast,however,andnon-irrigatedtallfescueandKentuckybluegrassareasaregoingdormantquickly.Someoftheseareasmayhaverootsystemsthatarecompromisedfromfloodedconditionsearlierinspring,whichwillresultinaquick

LawnDormancyLooms

dormancyflash.Justafewhundredmilestothenorthofus,historicfloodshavehittheWisconsinandChicagolandarea.Interestinghowmuchdifferenceafewhoursdrivenorthcanmakeinweather.

Afteramildblipinthenextfewdays,theheatisunfortunatelyforecastedtostayandevenintensifyintonextweek.Theregionisinamakeorbreakkindofscenariooverthenexttwoweeks.Norainoverthistimeframewilldrivetheareaintoamildtoevenmoderatedroughtsituation.

LawnDormancyLooms

QuickHits

• Anthracnose–Wehaveobservedmorebasalrotanthracnoseongolfputtinggreens

thisyearthananyIcanrememberinthepast.Foursamplesfrombentgrassputtinggreenshavebeendiagnosedwiththediseaseinthelasttwoweeks,andI’vebeenpostingaboutitsincelateMay(seetheposthere).Tochecksuspectareasyourself,investina10Xhandlens,pullacore,andlookatthecrownsofdecliningbentgrassforthejet-blackstructuresabove.Wetweatherandwildtemperatureswingsaretheprobablecauseforthisincrease,butitshouldalsobementionedthatanthracnoseresistanttoboththebenzimidazole(thiophanate-methyl)andQoI(azoxystrobin)chemistryhasbeenfoundinotherareasofthecountry.Donotrelyonthesechemistriessolelyforcontrol,androtateintheDMIsorCivitas(carefulduringhightemperatures),Velista,andotherfungicidesforcontrol.Bentgrassthatgoesintodroughtstressismoresusceptible,andconditionswillberipeforthat.AlsorememberanthracnoseisalowNdiseasesodon’tforgettofeedthebeast.Formorebestmanagementpracticesrelatedtoanthracnosecontrol,seetheguideproducedbytheRutgersresearchteamhere.

• PostApplicationIrrigation=SoilborneDiseaseControl–MycolleaguesatNorth

CarolinaStateareproofingthisequationthroughsoundresearch.AtatimewhensummerpatchisnibblingonKentuckybluegrassandcreepingbentgrassrootsandnematodesandPythiumrootrotareworkinginthegreensprofile,thisisavaluableandcriticalpoint.HearthemessageandseetheproofintheNCSUturfpathologyarticlehere.

LawnDormancyLooms

LawnDormancyLoomsLocalizeddryspotonbentgrassputtinggreenshasbeenoccurringsporadicallyoverthelastfewweeks,butreallytookholdoverthepastweek.Waterneedstomoveinaconstantandevenflowthroughthesoilprofile,andnotapreferentialflowfromwaterrepellencycausedbyorganicacidaccumulation.Ongreens,surfactantsmaybenecessarytokeepthisconsistency.Thislocalizeddryspotmaybeaprecursortosignificantdroughtdormancyoncommercialandhomelawns.Rememberthattallfescueismoredeeplyrooted,andgoesintoand,moreimportantly,comesoutofdormancywelleveninextendedboutsofdrought.Inthe2012drought,tallfescuethatwasn’twateredinconsistentlyandincompletelyrecoveredwell.Similarly,zoysiagrassshoulddojustfinewithalittlelesswaterthannormalandwillusuallypopbacktogreenwhenrainfallreturns.Monitoringforinsectactivityonzoysiagrassduringthisperiodwillbeimportant,however,toassurethatthebrownisnotduetochinchbugorbillbugactivity.Kentuckybluegrassandperennialryegrasswillsufferwithoutsomeirrigation,althoughnewercultivarsofKentuckybluegrasshaveshownmuchbetterheatanddroughttolerance.

LawnDormancyLooms

Ifacommercialorhomelawnistobeirrigated,(whichasstatedaboveisoftennotnecessaryforsurvival)pleaseremembertowaterearlyinthemorningforthesereasons.• Inthemorning,windsarenormallycalmsothedistributionofwaterismaximized.

• Evaporationandevapotranspirationisalsoatitlowest.Thesun’srayswillnotyetbake

thewaterbackintovapororboilitinyourrootzone.Soiltemperaturesmaybekeptlowerforabitlongerwiththecoolmorningdrink.

• Perhapsmostimportantly,foliardiseasessuchasbrownpatchandPythiummaybelimitedwiththispractice.Brownpatchneedsapproximately9hoursofleafwetnesstospark,andPythiumblightneedsapproximately13hours.Ifirrigationoccursatdusk,theleafwetnessperiodbeginsandonlyendswhenthesubsequentnighttimedewburnsoffwithsunlightthenextmorning.Conversely,wateringinthemorningrinsesoffthenightdewandmayactuallydisruptthemovementofthepathogenswhichisleaftoleafviamycelialgrowth.

Easymath.Waterat7pmandtheleafstayswetuntilthesunbakesitoff(iflucky)by8am.Thirteenhours.Dewsetsnaturallyatapproximately10pmandirrigationoccursaroundsunriseat6am.Eighthours.Waterearlyinthemorning.Theearlybirdreallydoesgettheworm.LeeMillerFollowonTwitter!@muturfpathLikeonFacebook!MizzouTurfgrassExtensionTurfgrassPathologist-UniversityofMissouri