montana ag alert - montana state university
TRANSCRIPT
MontanaAgAlertCroplandDisease6July,2017
Commonpulsecropdisorders:nutrient,droughtanddisease
TheSchutterDiagnosticLaboratory(andMaryandJessica’scellphones)haveseenalotofchickpeas,peas,andlentilslookingabitpeakedthesedays.Here’sarundownofthecommonthings:
1.Yellowchickpeas.Inthebeginning,theseplantswerescatteredandweputthecauseuptodamagedseed/’chickpeasjustdothat.’Now,wholefieldsareaffected,probablyexacerbatedbythehotdryconditions.Inmanycases,thelowerpartoftheplantisyellowwhiletheupperleavesaregreen.Itisverydifficulttodigpulsecroprootsoutofcement,somanyoftherootswehaveseenarestrippedandhaveveryfewnodules.Somehaverootrot,particularlyRhizoctoniarootrot.Wearespeculatingthatnodulationmayhavebeenpoorinthespring,andwiththehotdryconditionstheplantsareharvestingnitrogenfromtheolderleaves,causingthemtoturnyellowanddropoff.Picsbelow.Rootrotwouldexacerbatethisbynotallowingwatertoflowintotheleavesaswellashealthyroots.
Yellowedchickpeas.
Lowerleavesareyellow,rootshaveveryfewnodulesandsomehaverootrot.Upperleavesaregreen.Symptomscannotbetiedtoherbicidehistory.
PreviousresearchbyPerryMillerindicatedthat‘rescue’treatmentsofnitrogen8weeksafterplantinghadnobeneficialeffectonyieldofnon-inoculatedpulses,andnitrogenappliedinJulyisunlikelytomakeitintotherootzonebecauseofgenerallylowprecipitationamounts.2.Rootrotsonallpulses:Wearestartingtoseealotofpatchesofdecliningpulsecrops.Foliagemayinitiallybeyellow,androotsarebrownorblack.Theinitialcausemayhavebeenanotherfungus,butweareprimarilyrecoveringRhizoctoniarootrotatthispointintheseason.Norecoverytreatmentsareavailable.Usegoodcroprotationpracticesandaseedtreatmentintheupcomingyears.
3.Ascochytablightonchickpea:Wheretherearegoodcropswithacanopyandmorningdews,we’reseeingalotofascochytablightpopuponchickpea.Nothingonlentilandonlyscatteredreportsonpea.Fungicidesmaybeanoptioninchickpea,seetheearlieralertforrecommendations.Thediseaseshutsdownabove25-30C(77-86F),andpodfillalsodeclineswhenwehave90Fdays,soIwoulddelayanyfungicidedecisionuntilafterthelatestheatwaveifthereisnoevidenceofdisease.Ascochytamayresurgelaterintheseasonbutpayattentiontopreharvestintervalsonalllabels.
Ascochytablightsymptomsonchickpea
4.Bacterialblightonallpulses:Bacterialblightfollowshail.Distinctlesionsstopattheveins.SeethePulsecropdiseaseguideforphotosathttp://msuextension.org/pspp/documents/DiseasesofCoolSeasonLegumes.pdf
Thereisnotreatmentforthisdisease,usecleanseedlotsinfutureyears,particularlyifthediseaseaffectsthepods.
Asalways,contactusifyouhaveanyquestionsorconcerns.--MaryBurrows,599-9966,[email protected],994-5572,[email protected],994-5067,[email protected]