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dc.contributor.authorChandran, Rakesh Sarasammaen_US
dc.date.accessioned2014-03-14T20:21:32Z
dc.date.available2014-03-14T20:21:32Z
dc.date.issued1997-04-30en_US
dc.identifier.otheretd-2638232149731401en_US
dc.identifier.urihttp://hdl.handle.net/10919/30369
dc.description.abstractIsoxaben is a preemergence (PRE) broadleaf herbicide used in turf and ornamentals. Field, greenhouse, and laboratory research evaluated this herbicide for PRE control of selected broadleaves in turf, suspected postemergence (POST) herbicidal effects, and the influence of application timings and rates on soil residual. During seed germination in moist filter paper, isoxaben concentrations required for 50% inhibition of radicle growth (GR50) were 0.013, 0.010, 0.008, 0.008, and 0.007 ppm for dandelion, buckhorn plantain, white clover, black medic, and common lespedeza, respectively. In greenhouse experiments, isoxaben applied POST at 2.24 kg ai/ha suppressed the growth of Florida betony, black medic and white clover by 45, 65, and 66%, respectively, and reduced regrowth of Florida betony by 71%. In soil bioassays, yellow rocket control from isoxaben applied in fall was approximately 20 and 30% greater than spring-applied isoxaben at 3 and 6 MAT, respectively. Buckhorn plantain control from fall treatments at 3 MAT was approximately 15% higher than spring-applied isoxaben at 3 MAT. Application timings did not influence control of spotted spurge, a less sensitive weed. Isoxaben applied to turf in spring at 1.12 kg/ha provided > 90% control of buckhorn plantain, dandelion, and corn speedwell at 4 MAT. Fall applied isoxaben at the same rate provided total control of common chickweed, corn speedwell and henbit at 3 MAT and 80 to 90% control of white sweet clover and buckhorn plantain that germinated the following spring. Double (spring followed by fall) application of isoxaben to turf appeared to enhance broadleaf weed control in some instances. Dissipation of isoxaben in the top 3.8 cm of a Ross silt-loam soil as affected by spring, fall, and spring followed by fall applications was determined using high performance liquid chromatography (HPLC) analysis. Isoxaben residues in soil decreased by 55 and 92% by 3 and 6 MAT, respectively, for spring teatments, and decreased 29 and 52% by 3 and 6 MAT for fall treatments, respectively. A soil-bioassay study correlated well with chemical analysis of isoxaben residues, as the correlation coefficients were 0.85 and 0.89 for yellow rocket and buckhorn plantain, respectively.en_US
dc.publisherVirginia Techen_US
dc.relation.haspart1.pdfen_US
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dc.relation.haspart3.pdfen_US
dc.relation.haspart4.pdfen_US
dc.relation.haspart5.pdfen_US
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dc.relation.haspart7.pdfen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjecthalf-lifeen_US
dc.subjectpreemergenceen_US
dc.subjectherbicide fateen_US
dc.subjectdegradationen_US
dc.titleInfluence of Isoxaben Application Timing on Dissipation and Broadleaf Weed Control in Turfen_US
dc.typeDissertationen_US
dc.contributor.departmentPlant Pathology, Physiology, and Weed Scienceen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplinePlant Pathology, Physiology, and Weed Scienceen_US
dc.contributor.committeememberYoung, Roderick W.en_US
dc.contributor.committeememberHagood, Edward Scott Jr.en_US
dc.contributor.committeememberHall, John R. IIIen_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-2638232149731401/en_US
dc.contributor.committeecochairBingham, Samuel Wayneen_US
dc.contributor.committeecochairDerr, Jeffrey F.en_US
dc.date.sdate1998-07-12en_US
dc.date.rdate1997-04-30
dc.date.adate1997-04-30en_US


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