A study of the biology and control of the western flower thrips, Frankliniella occidentalis Pergande

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dc.contributor.advisorGiliomee, J. H.en_ZA
dc.contributor.authorBadenhorst, Jacqueline Anneen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Agricultural Economics.
dc.date.accessioned2012-08-27T11:36:51Z
dc.date.available2012-08-27T11:36:51Z
dc.date.issued1996
dc.descriptionThesis (M. Sc.) -- University of Stellenbosch, 1996.
dc.description.abstractENGLISH ABSTRACT: The effect of temperature on the development of Frankliniella occidentalis, Pergande on lima bean (Phaseolus limensis) leaf discs was investigated at five constant temperatures (15°, 18°, 22°, 25° and 30°C). Further studies examined the effect of temperature on reproduction and population growth at three constant temperatures (18°, 25° and 30°C). Life table studies showed that adult longevity and developmental rate of each life stage were inversely related to temperature. The prepetual and pupal stages showed greatest sensitivity to temperature. The nett replacement rate (R,) was highest at 25°C and th intrinsic rate of natural increase (r,) highest at 30°C. The generation time (T) declined with an increase in temperature. Fecundity of females peaked at 25°C. The minimum threshold for development was found to be 8.9°C and degree days for development ranged from 198.9 to 232.9. Populations of male and female F. occidentalis were monitored over an 18 month perdiod in a chrysanthemum glasshouse. Fluctuations in numbers female were significantly correlated to temperatures both within and outside the glasshouse, while male numbers showed no correlation at any time. Males outnumbered females at low population densities. When high numbers of thrips were caught, females formed more than 65% of the trapped individuals. The susceptibility of two strains F. occidentalis to endosulfan and formetanate was tested in residue on-glass bioassays in the laboratory. Diagnostic doses resulting in approximately 50 % and 90% mortality are proposed for endosulfan, namely 280 and 840 ppm a.i., respectively. Similarly diagnostic doses of 6 and 75 ppm a.i. are proposed for formetanate.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Die uitwerking van temperatuur op die ontwikkeling van Frankliniella occidentalis Pergande op boontjie (Phaseolus limensis) blaarskyfies is by vyf konstante temperature (15°, 18°, 22°, 25° and 30°C) bestudeer. Die effek van temperatuur op voortplanting en populasie-groei is ook by drie konstante temperature (18°, 25° and 30°C) bepaal. Volgens lewenstabelstudies nee die ouderdom van volwassenes, sowel as die ontwikkelingstempo met 'n toename in temperatuur af. Die pre-papie- en papiestadia het die hoogste sensitiwiteit teenoor temperatuur getoon. Die hoogste netto vervangingstempo (R,) is by 25°C verkry, terwyl die intrinsieke tempo van natuurlike toename (r,) die hoogste by 30°C was. Die generasietyd (T) het met 'n toename in temperatuur afgeneem. Vrugbaarheid het die hoogste vertoon by 25°C. Die drempelwaarde vir ontwikkeling was 8.9°C terwyl graaddae vir ontwikkeling tussen 198.0 en 232.9 gewissel het. Beide geslagte van F. occidentalis is oor 'n tydperk van 18 maande in 'n slaghuis, waarin krisante gekweek is, met behulp van geel kleefvalle gemonitor. 'n Betekenisvolle korrelasie is tussen die hoeveelheid wyfies wat gevang is en temperatuur gevind. Meer mannetjies as wysfies is in tye wanneer populasies laag was gevind. Wyfies het 65% of meer van die individue op die valle uitgemaak wanneer die populasie hoog was. Die vatbaarheid van twee rasse F. occidentalis vir endosulfan en formetanaat is met behulp van glasplaat-residu toetse in die laboratorium bepaal. Diagnostiese dossise wat nagenoeg 50 % en 90% mortaliteit tot gevolg gehad het, naamlik 280 en 840 dpm aktief, onderskeidelik, is vir endosulfan voorgestel. Diagnostiese dosisse van 6 75 dpm aktief is, op dieslefde manier, vir formetanaat voorgestel.af_ZA
dc.description.versionMastersen_ZA
dc.format.extent72 pages : illustrations.
dc.identifier.urihttp://hdl.handle.net/10019.1/55008
dc.language.isoen_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.rights.holderStellenbosch University
dc.subjectThrips -- Effect of temperature onen_ZA
dc.subjectThrips -- Developmenten_ZA
dc.subjectThrips -- Reproduction -- Climatic factorsen_ZA
dc.subjectThrips -- Biological controlen_ZA
dc.subjectDissertations -- Agricultureen_ZA
dc.subjectFrankliniella occidentalisen_ZA
dc.subjectUCTDen_ZA
dc.titleA study of the biology and control of the western flower thrips, Frankliniella occidentalis Pergandeen_ZA
dc.typeThesisen_ZA
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