Biological control of cogongrass, Imperata cylindrica (L.) Beauv.

205 Pages·2001·7.4 MB·English

by  Yandoc, Camilla B.

BIOLOGICALCONTROLOFCOGONGRASS.Imperatacylindrica(L.)
Beauv.
CAMILLAB.YANDOC
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTL\LFULFILLMENTOF
THEREQUIREMENTSFORTHEDEGREEOFDOCTOROF
PHILOSOPHY
UNIVERSITYOFFLORIDA
. ^ 2001 .
Copyright2001
by
CamillaB.Yandoc
Tomyparents,FranciscoandMariettaYandoc
ACKNOWLEDGMENTS
Iwouldliketothankmymajorprofessor,Dr.RaghavanCharudattan,for
believinginmeandforgivingmetheopportunitytoenrichmyselfbothprofessionally
andpersonally. IalsowouldliketothankDr.FrancisW.Zettlerandmycommittee
members,Dr.RichardD.Berger,Dr.JamesW.Kimbrough,andDr.DonnG.Shilling,
forthetime,interestandsupporttheyhavegivenme.ManythanksgotoJimDeValerio,
KarenHarris,JayGideon,HenryRoss,JasonMcCombs,MattPusateri,JoshRhames,
MarkElliott,EldonPhihnanandHermanBrownforallthehelptheyprovidedduringthe
courseofmyexperimentsandfortheirfriendship.Thanksgotomyformerlabmates.Dr.
ErinRosskopf,Dr.JugahKadir,Dr.S.Chandramohan,Dr.DauriTessman,Dr.Gabriela
Wyss,andMs.AngelaVincent. ThanksgotoallmyfriendsinthePlantPathology
Department,Mr.LuciousMitchell,Mr.GeneCrawford,theUSPS,thegraduatestudents,
Ms.LaurettaRhames,Ms.DonnaBelcher,KendraDavis,andMs.GailHarris,and
everyoneelsewhohelpedmeinonewayoranother. ManythanksgotoDr.Ziyad
MahfoudandMs.UpasanaSantraforhelpingmewiththedataanalysis.
Iwouldliketothankmyfamily,myMomandDad,mysisters.Carmenand
Guadalupe,brotherDeodato,mynephewsZygieandMickey,andmynieceMirandafor
alltheloveandsupport.ThanksgotomynieceIsabella,forremindingmetoalways
countmyblessings. ThanksgotoGino,forhislove,friendshipandpatience.Thanksgo
toAntonioandSheilaGomezandfamily.BobandPamKemerait,Dr.andMrs.Abies
. iv
and,andtoallmyfriendsbackhomeandallmyfriendsinGainesville.Finally,Ithank
Godforalwaysmakingthingsworkoutfine.
V
TABLEOFCONTENTS
ACKNOWLEDGMENTS iv
ABSTRACT ix
CHAPTERS
U-
1 INTRODUCTION .1.: 1
CogongrassIntroductionintotheUnited
States 7
EconomicandEcologicalImportanceof
Cogongrass 8
MorphologyandBiology 12
Habitat 14
CogongrassManagement 15
2 EVALUATIONOFFUNGALPATHOGENSASBIOLOGICAL
CONTROLAGENTSFORCOGONGRASS 23
- Introduction 23
MaterialsandMethods 25
Results 30
Discussion 37
3 MASSPRODUCTIONOFINOCULUMOFBipolarissacchari
ANDZ)recA5/erag/^an/eaANDDETERMINATIONOF "
OPTIMUMCONDITIONSTOMAINTAINSPORE " ' .
VL\BILITYDURINGSTORAGE 44
i ^ Introduction 44
MaterialsandMethods 49
vi
,
Results 54
Discussion 65
4 THEEFFECTOFOILFORMULATIONONTHE
BIOHERBICIDALEFFICACYOFBipolarissacchari
ANDDrechsleragigantea 70
Introduction 70
MaterialsandMethods 73
Results 79
Discussion 93
5 EVALUATIONOFHOSTRANGEOFBipolarissacchari
ANDDrechsleragigantea 97
Introduction 97
MaterialsandMethods 100
Results 102
Discussion 103
6 FIELDEFFICACYOFBipolarissacchariandDrechsleragigantea
ASBIOHERBICIDESOFCOGONGRASS Ill
Introduction Ill
MaterialsandMethods 116
Results 120
Discussion 136
7 SUPPRESSIONOFCOGONGRASSWITHBIOHERBICIDE
APPLICATIONANDPLANTCOMPETITION 142
Introduction 142
MaterialsandMethods 144
Results 148
Discussion 158
vii
.1
8 SUMMARYANDCONLUSIONS 162
REFERENCES. .168
BIOGRAPHICALSKETCH 194
: \ AbstractofDissertationPresentedtotheGraduateSchool
oftheUniversityofFloridainPartialFulfillmentofthe
RequirementsfortheDegreeofDoctorofPhilosophy
BIOLOGICALCONTROLOFCOGONGRASS
. . .w
CamillaB.Yandoc
December,2001
Chairman:RaghavanCharudattan
MajorDepartment:PlantPathology
Twofungalpathogens,BipolarissacchariandDrechsleragigantea,were
evaluatedfortheirpotentialasbiologicalcontrolagentsforcogongrass(Imperata
cylindrica[L.]Beauv.). Applicationofsporesuspensionsofeachofthesefungithat
containedlO'*-10^spores/mland1%gelatinresultedin30-50%diseaseseverity,ona
ratingscalewith50%asthemaximumdiseaseseverity. Diseasesymptomsrangedfrom
foliarlesionstoblighting. Sporesformulatedinanoilemulsioncausedmoredisease
severityinthegreenhousetrials. Massproductionofsporeswasachievedinthe
laboratorywithsohdsubstrateculturingtechniques. Sporesdriedat30-40''Cfor5days
andstoredatlowtemperature(10-25°C)andlowhumidity(30-60%)RH)remainedviable
foratleast10weeks. Inhost-rangetests,19plantspeciesinsixfamilies(Alliaceae,
Apiaceae,Asteraceae,Cucurbitaceae,Poaceae,andSolanaceae)werefoundtobe
ix
susceptibletoB.sacchariformulatedinoilemulsion. Susceptibilityofthespecies
outsidethefamilyPoaceaewasattributedtothepredispositionofthetestplantsbytheoil
formulationandtheirageandvigor. ^ '
Amongtheresistantgrassspecieswasbahiagrass,acommonlyusedturfand
pasturegrassspeciesinFlorida. Inexperimentsinthegreenhouse,B.sacchari |
selectivelycontrolledcogongrassandreduceditsabilitytocompetewithbahiagrassin
cogongrass-bahiagrassmixtures. Thus,B.saccharicanbeusedtosuppresscogongrass
andtoallowtheestablishmentofamoredesirablespecies,suchasbahiagrass.
Infieldtrials,therewasasignificantinteractionofthesporeconcentration,oil
concentrationofthecarrier,andapplicationvolumeontheefficacyofB.sacchariandD.
gigantea. Generally,applicationofalargervolumeofinoculum(800ml/m^)that
contained10^or10^spores/mland18or26%oil,appliedwithahand-pumpedsprayer,
resultedinthehighestlevelsoffoliarblighting(>70%onaratingscaleof0-100%)
duringthe6-weekexperimentalperiod. Applicationof5.sacchariandD.gigantea,
singlyorasamixtureattherateof200ml/m with10 spores/mlwithanultra-low-
volume-applicatorresultedin>70%diseaseseverityinthefield. Bipolarissacchariand
D.giganteahadtheefficacytobebiologicalcontrolagentsofcogongrass.