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Permanent Link: http://ufdc.ufl.edu/IR00002378/00001
 Material Information
Title: Diagnosing Dooryard Citrus Problems
Physical Description: Fact Sheet
Creator: Jackson, Larry K.
Publisher: University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication: Gainesville, Fla.
Publication Date: 1995
 Notes
Acquisition: Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status: Published
General Note: "Revised: May 1992. Reviewed: January 1994. Revised: September 1995."
General Note: "HS-34A"
 Record Information
Source Institution: University of Florida Institutional Repository
Holding Location: University of Florida
Rights Management: All rights reserved by the submitter.
System ID: IR00002378:00001


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FactSheetHS-34A September1995DiagnosingDooryardCitrusProblems1 LarryK.Jackson2CitrusisgrowninmanyareasofFloridaandin mostsituationscanbecultivatedwithonlyroutine care.However,theFloridaclimateisconduciveto manydifferentinsects,diseasesandotherdisordersin thedooryardsituationwheremanydifferenttypesof plantsaregrownincloseproximitymaypromote certainproblems.Diagnosisofthemanyproblems whichcanafflictcitrusisoftendifficult,sothis publicationhasbeenpreparedtoassistdooryard growerswiththistask.Thevariousproblemshave beenseparatedbywheretheymaybelocated-the fruit(Table1),theleaves(Table2),orotherportions ofthetree(Table3).Then,ageneraldescriptionis givenandbriefsuggestionsforcontrolareprovided. Moreaccuratediagnosiscanbemadewhenfresh specimensoftheproblemcanbetakentolocalIFAS CountyExtensionofficesortolocalgardensupply centers. Manyoftheproblemsarenon-pestandspraying isnotwarranted.Evencertainpestproblemscanbe dealtwithbiologicallyandspraysareoften unnecessary.Ifchemicalcontrolmeasuresare warranteditisimportanttofollowlabelinstructions explicitlytopreventharmtotheapplicator,thetree ortheenvironment.TableTable1.1.ProblemsofFruit. UsualCause WhenUsuallyNoticed WhenUsually Occurred Control Symptom:Fruitdropsprematurely Physiologicaldisorderor disease.Variouscauses. Mostacuteatbloom, duringJune,andnear harvest. Throughoutseason Followrecommended culturalpractices. Comment:Someearlydropisnormalsincetreesoftenover-bear.Prematurefruitdrop(PFD)disease maysometimesaffectveryyoungfruit,resultingindropwithcalyxremainingonstem. Symptom:Fruitisrustyorbrownwithsmoothtexture. Citrusrustmite Whenfruitsizesand beginstomature. Usuallyduringfruit development. Checkforrustmites andsprayifneeded. Comment:Primarilyacosmeticproblem. Symptom:Splittingoffruit 1.ThisdocumentisFactSheetHS-34A,aseriesoftheHorticulturalSciencesDepartment,FloridaCooperativeExtensionService,Institute ofFoodandAgriculturalSciences,UniversityofFlorida.Revised:May1992.Reviewed:January1994.Revised:September1995. 2.LarryK.Jackson,emeritusprofessor,HorticulturalSciencesDepartment,CitrusResearchandEducationCenter(CREC),LakeAlfred, FL,abranchcampusoftheUniversityofFlorida,InstituteofFoodandAgriculturalSciences,UniversityofFlorida,GainesvilleFL32611. TheInstituteofFoodandAgriculturalSciencesisanequalopportunity/affirmativeactionemployerauthorizedtoprovideresearch,educational informationandotherservicesonlytoindividualsandinstitutionsthatfunctionwithoutregardtorace,color,sex,age,handicap,ornational origin.Forinformationonobtainingotherextensionpublications,contactyourcountyCooperativeExtensionServiceoffice. FloridaCooperativeExtensionService/InstituteofFoodandAgriculturalSciences/UniversityofFlorida/ChristineTaylorStephens,Dean

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DiagnosingDooryardCitrusProblems Page2TableTable1.1.ProblemsofFruit. UsualCause WhenUsuallyNoticed WhenUsually Occurred Control Physiologicaldisorder Priortoandduring harvestseason. Justpriortofruit maturity. Avoidwaterstress, followfertilizer recommendations. Comment:Notreversible.Followrecommendedpracticesnextseason. Symptom:Smoothbrownortanirregularblemishesonpeel. Mechanicaldamagefrom abrasion. Nearharvest Usuallywhenfruitis small. Nocontrolavailable. Comment:Acosmeticproblem Symptom:Black,smuttycoveringoffruit Sootymoldfungus Priortoandduring harvest. Summer Controlinsectswhich causeproblem. Comment:Thefungusgrowsonexudatesfromscales,whitefliesandaphids. Symptom:Granulation,dryingofjuicesacs. Physiologicaldisorder Atharvest Nearharvest Regularirrigation. Goodcultural practices. Comment:Problemisworseonyoungorvigoroustrees. Symptom:Thickpeel Physiologicaldisorder Atharvest Nearharvest Followgoodcultural practices. Comment:Worseontreeswhichareyoungoroverfertilized,recentlypruned. Symptom:Raisedscabbybumpsonfruit Citrusscabfungus Anytimefruitisontree Shortlyafterbloom Preventivespray program Comment:Affectsonlycertainvarieties Symptom:Brown,pinhead-sizedraisedlesionsonfruitabout1/16"diameter. Melanosefungus Summertillfruit harvest. Latespring Preventivespray program.Remove deadwood. Comment:Sprayswillnotreversedamage,mustbeprevented. Symptom:Grapefruitrindpitting Greasyspotfungus Atornearharvest Summer Preventivespray program. Comment:Acosmeticproblem Symptom:Raisedspecksorspotsofvariouscolors,usuallylessthan1/10",removable. Scaleinsects(therearemany types). Anytime Summer,fall Sprayifpopulation warrantscontrol. Comment:Highpopulationsaffecttreevigor. Symptom:Prematurecoloring,blackdecayinfruitcore. Blackrotfungus Latefall Earlyfall Removeaffected fruit.

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DiagnosingDooryardCitrusProblems Page3TableTable1.1.ProblemsofFruit. UsualCause WhenUsuallyNoticed WhenUsually Occurred Control Comment:Aninfrequentproblem Symptom:Prematurecoloring,verysmallpuncturewounds,somefruitdrop. Plant/stinkbuginjury Latesummer,earlyfall Latesummer,early fall Watchforinsectsand sprayifnecessary. Comment:Aninfrequentproblem Symptom:Tan,leatherydecaywithfoulodor. Brownrotfungus Nearharvestand postharvest Justpriortoharvest Preventivespraymay behelpfulifproblem isrecurrent. Comment:Aninfrequentproblem.Spraywillnotreverseexistingdamage. Symptom:Crease-like,depressedlinesinfruitpeel. Physiologicaldisorder (creasing). Priortoorduring harvest Summer Followgoodcultural practices. Comment:Anoccasionalproblemofcertainvarieties. Symptom:Discolored,oftennecroticsunkenareasofdamagetopeel. Chemicalburn Anytime Anytime Usuallyresultsfrom impropersprayrates orapplication. Comment:Spraysmustbeappliedproperlyobservingalllabelinstructions. Symptom:White,cottonymassesusuallylocatedaroundstem. Mealybugsorcottony-cushion scaleinsects. Anytime Summer Sprayshouldbe appliedifpopulation warrants. Comment:Onlyanoccasionalproblem.Highpopulationmaycausefruitdrop. Symptom:Black,raisedbumpsonfruitstemabout1/8"diameter. Blackscaleinsects Nearharvest Latespring Sprayshouldbe appliedifpopulation warrants. Comment:Highpopulationscancausefruitdrop. Symptom:Holesinfruitofvarioussizes,depths. Chewinginsects,birdsor rodents. Nearharvest Nearharvest Observetodetermine causeofproblem. Comment:Controlmeasureswilldependonnatureofproblem.TableTable2.2.ProblemsofLeavesandTwigs. UsualCause WhenUsually Noticed WhenUsuallyOccurred Control Symptoms:Black,soot-likecoveringonleaves. Sootymoldfungus Anytime Mainlyspring,summer Needtocontrolpests whichcauseproblem.

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DiagnosingDooryardCitrusProblems Page4TableTable2.2.ProblemsofLeavesandTwigs. UsualCause WhenUsually Noticed WhenUsuallyOccurred Control Comment:Thefungusgrowsonexudatesofscales,whiteflies&aphids. Symptom:Distortion,curlingand/orcuppingofleaves. Aphidsand/orcitrus leafminer Anytime Mainlyspring,summer whenleavesweretender Controlinsectsonplant. Cannotreversedamage. Comment:Controllinginsectswillpreventtheproblembutwillnotrepairexistingdamage. Symptom:Scratched,silveryappearancetoleaves. Spidermites,usuallycitrus redmite Anytime Mainlyspring,fall Controlspidermites. Comment:Maycauseleafdropinfallwithsevereinfestations. Symptom:Leavescut,chewedornotched. Chewinginsectssuchas grasshoppers,crickets, weevils. Anytime Anytimebutusually duringwarmermonths Difficult-probablybest removedbyhand Comment:Usuallynotaseriousproblem. Symptom:Leavesdistorted,oftenwithbumpy,scabbylesions. Scabfungus Anytime Duringspringgrowth flushperiod. Requireswell-timedsprays oruseresistantvarieties. Comment:Mustbeprevented,spraywillnotcorrect.Maybeonfruit,twigsalso. Symptom:Darkbrownpinhead-sizedpustuleswithsandpapertextureonleafsurface. Melanosefungus Anytime Latespring-early summer Preventivesprayprogram. Removedeadwood. Comment:Sprayswillnotcorrect.Mayattackfruit&twigsalso. Symptom:Darktar-likespotsonleavesusuallylessthan1/8"indiameter. Greasyspotfungus Anytime Summer Preventivesprayprogram. Removefallenleaves undertree. Comment:Sprayswillprevent,notcorrectexitingproblem.Severecaseswilldefoliate. Symptom:Raisedspecksorspotsofvariouscolorsusuallylessthan1/10",removable. Scaleinsects(thereare manytypes). Anytime Summer,fall Spraywhenpopulation warrantscontrol. Comment:Highpopulationsaffecttreevigor.Mayalsoattackfruit,twigs. Symptom:White,cottonymassesonleaves,twigs,fruit. MealybugsorCottonycushionscaleinsects. Anytime Spring,summer Handremovalorsprayif warranted. Comment:Usuallynotseriousexceptonsmallplantsbutmaycausefruitdrops. Symptom:Small(1/16")translucentdiscsunderleaveswithwhiteflyinginsectspresent. Whiteflies Summer Latespring,summer Sprayifpopulation warrantscontrol. Comment:Sootymoldmaybemoreofaproblemthanwhiteflies.

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DiagnosingDooryardCitrusProblems Page5TableTable2.2.ProblemsofLeavesandTwigs. UsualCause WhenUsually Noticed WhenUsuallyOccurred Control Symptom:Leafnecrosisattipormargin.Maybesomedrop,twigdeath. Saltaccumulationfrom waterorfertilizer. Anytime Anytime Checkwatersupply, reducefertilizer. Comment:Irrigatewithfreshwatertoleachsaltsfromroots. Symptom:Redoryellowraisedspotsabout1/12"onundersideofleaves. Aschersoniafriendlyfungus whichattackswhiteflies. Anytime Summer Donotcontrolasthisisa friendlyfungus. Comment:Thisfungusattackstheimmaturewhitefly. Symptom:Leafdrop,oftenfollowedbytwigdieback. Rootdamage,mostoften duetoflooding. Anytime Anytime Avoidexcesswater. Comment:Iffloodinghasoccurred,treemayneedtoberemoved,replaced. Symptom:Palegreenleaves,oftenundersized. Fertilizerdeficiency, possiblerootdamage. Anytime Anytime Followfertilizer recommendations.Check forroot,trunkdamage. Comment:Checktrunknearsoillineforfunguslesions. Symptom:Palegreenleaveswithdarkergreenveins. Nutrientdeficiency-usuallymicroelements. Anytime Anytime Nutritionalsprayneeded. Comment:Followfertilizerandnutritionalsprayrecommendationscarefully. Symptom:Leafyellowing,necrosis,someleafdrop. SprayBurn--Maybesaltor chemical Anytime Anytime Washoffexcessive residues.Avoidexcess ratesofspray. Comment:Saltsprayisoftenaproblemneartheocean.TableTable3.3.ProblemsofLimbs,TrunkorEntireTree. UsualCause WhenUsuallyNoticed WhenUsuallyOccurred Control Symptom:White,snow-likespecksonbarkoflimbs,trunk. Citrussnowscale Anytime Anytime Removemechanically orusechemicalsprays. Comment:Severeinfestationsmaycauselimbloss,fruitdrop. Symptom:Treedeclines,smallyellowishleaves,barklesionsnearsoiloftenpresent. Footrotfungus Anytime Anytime Removeanyorganic materialneartrunk, disinfectarea. Comment:Curewillbedifficult.MayneedtocontactExtensionofficeorlocalnursery.

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DiagnosingDooryardCitrusProblems Page6TableTable3.3.ProblemsofLimbs,TrunkorEntireTree. UsualCause WhenUsuallyNoticed WhenUsuallyOccurred Control Symptom:Treedeclineswithoutoutwardobvioussymptoms. Blight,virusdisease, nematodes,orweevils. Anytime Anytime Nocontrolavailablefor theseproblems. Comment:Diagnosisofactualproblemwilllikelybedifficult.LocalExtensionofficemaybeableto help.