Characterization of soilborne fungi associated with peanut (Arachis hypogaea L.) in Florida

360 Pages·2000·12.1 MB·English

by  Kemerait, Robert Chester

ACHARACTERIZATIONOFSOILBORNEFUNGIASSOCIATEDWITH
PEANUT(ARACHISHYPOGAEAL)INFLORIDA
By
ROBERTCHESTERKEMERAIT,JR.
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
2000
To
JanetandRobertKemerait
ACKNOWLEDGEMENTS
Thisprojecthasbeenachallengefromitsinception. Iamindebtedto
manypeoplefortheirsupport,advice,andencouragementinmygrowthasa
plantpathologistandinthecompletionofthisstudy. Thesuccessofthisworkis
areflectionoftheircommitmenttome;anyfaultsinthisworkaremyown.
Dr.TomKucharekhasbeenamentorsinceIbeganthesegraduate
studiesandhasprovidedmewithmanyopportunitiesunavailabletoother
students. Hehasgivenmethechancetoworkwithgrowersinthefieldandthen
allowedmethelatitudetopursuethisresearchindirectionsthatwererewarding
andexcitingtome. Hisgenerosityoftimeandthefinancialresourceshavebeen
unfailing. Hehashelpedtofocusmypassionforappliedplantpathologyand
extensionworkandpreparedmeforarewardingcareerofservicetothegrower.
IwouldliketothankDr.GeorgeAgriosforhissupportthroughoutmystay
inthePlantPathologyDepartment. SinceourfirstmeetinginFebruaryof1994,
hehasputtheutmostfaithinmypotentialtosucceedasaplantpathologistand
providedsupporttomeduringmuchofmytimeinthedepartment.
IamindebtedtoDr.LancePetersonandDowAgrosciencesfortheir
generousfinancialsupportduringthefirstthreeyearsofmygraduateprogram.
Withoutthisearlysupport,Imayneverhavebeenabletobeginmyprogramwith
Dr.Kucharek.
iii
Iappreciatethecontributionsofthemembersofmyadvisorycommittee,
Dr.RichardBerger,Dr.DavidMitchell,Dr.LancePeterson,Dr.FredShokes,
andDr.BenWhittytothecompletionofthisprogram. Theyhaveprovided
guidance,suggestions,critiques,andencouragementthroughoutthemany
strugglesofthisproject. Iamespeciallygratefulforthecarethattheyspentin
theeditingandreviewofmydissertation.
Iamveryappreciativeoftheassistance,mentoring,advice,and
encouragementgiventomebyDr.JimKimbrough,Dr.DanPurcifull,andDr.
GeraldBenny. Theirhelpwasinvaluableandtheirkindnesswillnotbeforgotten.
IamfortunatetohavebeenabletoworkinDr.Kucharek'slabwithDr.
KennySeebold,Mr.RonHoover,Mr.CharlesSemer,Ms.MistyNielsen,Mr.
AnthonyDyess,andMr.MikeMahovic. Theyallcontributedexpertiseand
countlesshoursoftimeandeffortformysake. Mr.RonHooverbuiltthe
sterilizationboxesthatIusedsooftenduringthisstudyandMr.ChuckSemer's
experiencewithgeneralplantpathologyallowedmetoaddnewandimportant
facetstomyresearch.
Iappreciatethehelpofthecountyextensionagentsandthegrowerswho
sogenerouslysharedtheirtime,knowledge,andresourceswithmeduringthis
research. Thisprojectcouldnothaveoccurredwithouttheircooperation. In
SantaRosaCounty,IowegratitudeandthankstoMr.JohnAtkins,Mr.Greg
Kimmons,Mrs.JaniceSimmons,Mr.KeithRoland,Mr.MillardHolley,andMr.B.
D.Hendricks. InJacksonCountyIowemanythankstoMr.EdJowers,Mr.John
Stone,Mr.TedBaxter,andMr.ChuckDickson. InSuwanneeCounty,I
iv
appreciatethehelpofMr.BobTervola,Mr.EddieRoberts,Mr.RobertBarnett,
Mr.BobBarnett,Mr.KennethHallofSuwanneeFarms,andMr.JimmyDaniels.
InColumbiaCounty,IappreciatethehelpofMr.BillThomasandMr.Lamar
Mosely. InLevyCounty,IamindebtedtoMr.AnthonyDrew,Mr.DuaneFugate,
Mr.GeneFugate,Mr.JeffFugate,Mr.SteveFugate,andMr.FreddieBell.
appreciatethegeneroushelpprovidedtomebythefacultyandstaff
I
fromotherdepartmentsattheUniversityofFloridaandfromthevariousresearch
facilitiesaroundthestate. Mr.JayHarrisonfromIFASStatisticsspentmany
hourshelpingmewithstatisticsandintroducedmetocorrespondenceanalysis.
Hispatiencewasablessing. Mr.JimBartosattheIFASSoilsLabspentwas
helpfulintheprocessingofsoilsamples. FromtheDepartmentofEntomology
andNematology,IwasassistedbyDr.DonDickson,Mr.TomHewlett,Mr.
ReggieWilcox,andMr.FrankWoods. AttheGreenAcresAgronomyFarmnear
Gainesville,IreceivedgeneroushelpandsupportfromMr.HarryWood. Atthe
NorthFloridaResearchandEducationCenterinQuincy,Ireceivedtremendous
supportfromDr.DanRhodes,Mr.DonBerger,Mr.JohnAllenSmith,Mr.Ray
Jordan,Mr.ClaudeButler,andMr.LeroyMarshall,andMr.RayBass.
IamindebtedtoMr.LuciousMitchell,Mr.GeneCrawford,Ms.GailHarris,
Ms.LaurettaRhames,Ms.KarenOwens,Ms.PollyTeale,andMs.PattiRayside
fortheirassistanceduringthepastfiveyears.
MyexperienceinthePlantPathologyDepartmentattheUniversityof
FloridahasbeengreatlyenhancedbythemanyfriendsthatIhavemadeamong
thestudents. IamespeciallygratefulfortheassistancegiventomebyDr.Erin
v
Rosskopf,Dr.KennySeebold,Dr.CarlosForcellini,Dr.DauriTessman,Dr.
DanielaLopes,andDr.BobHarveson. Theyinspiredmetopursuemyresearch
withdedicationandperseverance.
IwillalwaysbeindebtedtoJanetandRobertKemeraitforthe
opportunitiesandencouragementthattheyprovided. AnysuccessthatIattain
wouldnothavebeenpossiblewithoutthem. TheyknewIcouldevenwhenI
didn't.
Finally,Iamgratefulforthesupport,trust,andfaiththatmywife,Pam,
hasputinme. Myresearchhasbeencontinuallydemandingandhasrequired
muchattentionandtravelawayfromhome. Hersupporthasneverwaveredand
hasinspiredmetoattaingoalsthatIotherwisemightnothavesought.
vi
TABLEOFCONTENTS
page
ACKNOWLEDGMENTS
iii
LISTOFTABLES ix
LISTOFFIGURES xi
ABSTRACT xviii
CHAPTERS
1 INTRODUCTION 1
2 LITERATUREREVIEW 5
ArachishypogaeaL 5
OriginofthePeanut 7
Taxonomy 7
ThePeanutPlant 9
PeanutProductionPracticesintheUnitedStates 13
SoilborneFungi 19
InventoriesofSoilborneFungi 22
ComplexesofSoilborneFungi 25
EnvironmentalInfluencesonSoilborneDiseases 27
CultivationPracticesandRotationinSoilborneDiseaseinPeanut 29
UseofFungicidesintheControlofSoilborneDiseaseinPeanut 30
InfluenceofCropDevelopmentonFungalInfection 31
3 SOILBORNEFUNGIISOLATEDFROMPEANUTPLANTS 37
Introduction 37
MaterialsandMethods 39
Results 59
Discussion 80
Conclusion 91
vii
4 VARIABLESRELATEDTOINCIDENCEOFSOILBORNEFUNGI 92
Introduction 92
MaterialsandMethods 93
Results 101
Discussion 134
Conclusions 151
5 SOILBORNEFUNGIANDTHREECULTIVARSOFPEANUT 153
Introduction 153
MaterialsandMethods 156
Results 164
Discussion 202
Conclusions 215
6 FUNGICIDESANDTHEINCIDENCEOFSOILBORNEFUNGI 217
Introduction 205
MaterialsandMethods 220
Results 225
Discussion 261
Conclusions 273
7 INFLUENCEOFFOLIARDISEASEONSOILBORNEFUNGI 276
Introduction 276
MaterialsandMethods 278
Results 283
Discussion 305
Conclusions 311
8 SUMMARY 313
REFERENCES 321
BIOGRAPHICALSKETCH 338
viii
LISTOFTABLES
Table page
Table3-1.Characteristicsandculturalinformationcollected
fromfieldsofpeanut(ArachishypogaeaL.)inFloridain1995 42
Table3-2.Characteristicsandculturalinformationcollected
fromfieldsofpeanut(ArachishypogaeaL.)inFloridain1996 43
Table3-3.Yieldsandfungicideinformationforcommercialfields
ofpeanut(ArachishypogaeaL.)inFloridain1995and1996 44
Table3-4.Numberofplantsevaluatedfromeachsiteduring
samplingphaseofpeanutfungalsurvey 47
Table3-5.Growthstagesofpeanut 48
Table3-6.Numericschemetoevaluatepeanutplanthealth
attimeofprocessing 49
Table3-7.Fungalisolatesusedininoculationstudies 53
Table3-8.Incidenceoffungiduringpeanutseedlingandvegetativestages 63
Table3-9.Abundanceofsoilbornefungiisolatedfromcommercial
andresearchpeanutfieldsinFloridaoveranentireseason 65
Table3-10.Percentageoffieldsfromwhichfungiwereisolated
baseduponfiveregionsinFlorida 68
Table3-11.Relativepathogenicityoffungalisolatesinoculated
intofive-week-oldpeanutplants 71
Table3-12.Pathogenicityofselectedfungalisolatesinoculated
intoFlorunnerpeanutatfivedifferentagesandgrowthstages 73
Table3-13.Pathogenicityofselectedgeneraoffungi25daysafter
inoculationof14-dayFlorunnerpeanutseedlingsatthree
differenttemperatures 75
Table3-14.Competitiveinteractionsbetweenpathogenicisolates
andselectednon-pathogenicantagonists 77
Table4-1.Rangeofcropagesandpeanutgrowthstagesforsequential
samplingdatesduring1995and1996 99
Table4-2.Pearson'scorrelationcoefficientsforincidencesof
selectedsoilbornefungifromallcommercialfieldsthat
weresignificantand>0.1or<-0.1 inthecombined1995
and1996seasons 103
Table4-3.Pearson'scorrelationcoefficientsforincidenceof
selectedsoilbornefungiandfieldfactorsthatwere
significantand>0.10.1or<-0.1 inboth1995and1996 104
ix
1
Table4-4.Maineffectsandinteractionsofsamplingtripandplantparton
recoveryofeightsoilbornefungalpathogensofpeanutfromcommercial
fieldsinFloridaduriing1995and1996 109
Table4-5Meanincidencesofspecificsoilbornefungias
relatedtotheyearandtimeofseasonwhenplantswere
sampledandpartoftheplantfromwhichthefunguswasisolated 11
Table5-1.SamplinginformationfromacultivartrialattheNorthFlorida
ResearchandEducationCenter,atQuincy 165
Table5-2.Yieldanddiseaseseverityamongthreecultivars
ofpeanutgrownattheNorthFloridaResearchandEducation
Center,Quincyduring1998and1999 166
TableSa6n-t1a.SRaomspaliCnogunitnyf,orFmlaotriiodnafromfungicidetrialsonpeanut, 226
Table6-2.Yieldanddiseaseseverityduring1998and1999
associatedwithfourfungicideprogramsonpeanutin
SantaRosaCounty,Florida 227
Table7-1.Samplinginformationfromaleafspottrialforpeanut,Suwannee
County,Floridain1998 280
X