Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The foraging mode of the Cape grass lizard, Chamaesaura anguina, was determined by using three criteria: 1) the number of movements per minute (MPM) and the percentage of time spent moving (PTM) during periods of activity; 2) the amount of tongueflicking directed at cotton applicators labelled with prey chemicals as a measure of prey chemical discrimination; 3) the stomach contents of the lizards as an indication of the natural diet. Observations were made by means of binoculars from an observation tower using a seminatural outdoor enclosure, and through a one-way glass panel using a seminatural indoor enclosure. Each lizard was observed for aIO minute period during peak activity and the times it was moving and the times it was stationary were recorded. Data obtained in the indoor- and outdoor enclosures did not differ significantly and were pooled. "MPM(0.37 ± 0.21 SD) and PTM (1.92 % ± 0.93 SD) values recorded for C. anguina (N = 10) fall within the range given as characteristic for sit-and-wait foragers. Nine C. anguina individuals were habituated in glass terraria to accept mealworms offered to them. When all lizards accepted food without hesitation, they were tested for their ability to discriminate among three different odours presented to them in a randomized block design: prey odours consisting of mealworm surface odours, distilled water as an odourless control stimulus, and cologne as a pungency control. The number of tongue-flicks directed at the cotton applicator containing the stimulus odour during 60 s was recorded. No statistically significant differences were found among the responses to the three treatment odours (Kruskal-Wallis, H = 2.41, dj = 2, P = 0.30). An analysis of the stomach contents of21 C. anguina specimens revealed a diet of mostly diurnally active arthropod prey species. The preferred body temperatures selected by 12 grass lizards in a thermal gradient were measured six times during a 48 hour period, using a copper-constantan thermocouple inserted into the cloaca. The measured body temperatures (N = 72) ranged from 22.62 oe - 27.07 oe with a mean of24.82 oe ± 2.27 SD. The low preferred body temperature exhibited by C. anguina as compared to other cordylids may be attributed to the combined influence of vegetative cover, high altitude, and high surface-volume ratio. To determine movement patterns and microhabitat use, six lizards were observed in a seminatural outdoor enclosure (4 x 4 m). The location of the grass tufts in the enclosure was mapped, and the position of each lizard within the enclosure was noted on 17 mornings. Observations of lizard behaviour during periods of activity were made by means of binoculars from an observation tower. Although C. anguina did not show reliance on a specific shelter site, the taller, broader tufts were generally preferred as refuges during inactivity. There were significant differences between the heights (student's z-test; P < 0.001) and the diameters (Mann-Whitney; P < O.00 1) of the preferred grass tufts, and those grass tufts that were not preferred as refuges, respectively. The lizards usually sheltered in a coiled-up position in the middle of the grass tufts close to the ground. During active periods, the lizards perched in an elevated position in the vegetation by entangling their elongated bodies and tails in the grass for efficient weight distribution. Locomotion was mainly restricted to the strike action when attacking prey. Fynbos and grassland, which are the main habitat of grass lizards of the genus Chamaesaura, are fire-prone. With their serpentiform morphology, grass lizards differ markedly from other cordylids, the majority of which are rock-dwelling. One aim of this study was to determine whether grass lizards make use of refuges like burrows or crevices within their grasslrestioid habitat during periods of inactivity or when threatened by fire. Refuge selection during inactivity was determined experimentally. Twelve lizards were offered different refuge options, namely grass tufts, crevices, burrows and loose sand. All twelve lizards preferred to shelter in the grass tufts. When the grass tufts were removed, only two lizards made use of the burrows and crevices provided, the other 10 not sheltering at all. Refuge selection when threatened by fire was tested by placing the 12 lizards in an enclosure provided with grass tufts and two types of refuges, burrows and crevices. The grass was set alight at one end of the enclosure and the fire was fanned on towards the other end with the aid of a high-speed fan. Precautions were taken to ensure the safety of all the lizards and to intervene when they were in direct danger. Only two of the 12 lizards sought shelter in the refuges provided. Of the remaining 10, six fled and four were trapped by the flames, requiring intervention. The results of these experiments, as well as field observations, suggest that C. anguina seldom makes use of shelter options other than grass and restio tufts, even when threatened by fire. In the case of fire, it flees by 'grass-swimming'. Field observations also suggest that mortality during and after a fire is considerably higher than in the case of rock-dwelling cordylids. The reproductive status of adult females (N = 85) were determined on the basis of the developmental stage of ovarian follicles and the presence or absence of oviductal eggs. Females were grouped into four reproductive categories: pre-vitellogenic, early vitellogenic, pre-ovulatory and gravid. To determine the reproductive cycle exhibited by the males (N = 46), testicular volume and seminiferous tube diameter were measured, as well as the spermatogenic activity assessed qualitatively. Spermatogenic activity was assessed by using Licht's (1967) classification system. The snout-vent length (SVL) of 144 specimens was measured. Sexual size dimorphism (SSD) recorded for C. anguina was quantified by a size dimorphism index (SDI). Reproductive activity was asynchronous among females, differing from the normal cordylid cycle of autumn/winter vitello genic activity, followed by winter/spring ovulation and gestation in late summer to autumn. The significant seasonal variation that existed in testes volume (ANOVA; F (7,22) = 3.70; P < 0.05) and seminiferous tubule diameter (ANOVA; F (10,25) = 4.90; P < 0.05), as well as sermatogenic activity as observed by histological examination, indicated that C. anguina males follow an annual spermatogenic cycle that can be described as post-nuptial. The cycle is characterized by summer/autumn spermiogenesis, associated with sperm storage throughout winter. Chamaesaura anguina males differ from other cordylids following a post-nuptial cycle, by starting with spermatogenesis in spring. The mean SVL of female grass lizards (109.51 mm ± 20.60 SD) was significantly larger (Mann-Whitney; P < 0.001) than that of males (84.77 mm ± 9.39 SD). A positive SDI of 1.29 and a SDImax of lAO were determined. Female-biased dimorphism in SVL recorded for C. anguina corresponds with the general pattern recorded for terrestrial cordylids, but contrasts with male-biased dimorphism in rupicolous forms. The longer SVL of C. anguina females facilitates higher fecundity. This, in turn, might be an adaptive survival strategy for this lizard species in the fire-prone environment where it occurs, because successful recruitment is facilitated by high fecundity. KEYWORDS: Chamaesaura anguina; serpentiform body; cryptic colouration; grass/restio habitats; undulatory locomotion; foraging mode; preferred body temperature; movement patterns; microhabitat use; fire susceptibility; refuge selection; reproductive cycle; sexual size dimorphism. 4 / AFRIKAANSE OPSOMMING: Die voedingswyse van Chamaesaura anguina is bepaal deur drie kriteria: 1) die getal bewegings per minuut (BPM) en die persentasie tyd wat aan beweging bestee word (PTB) tydens aktiewe periodes; 2) die hoeveelheid tongskiete wat gerig word na wattepluisies bedek met prooi chemikalieë as 'n maatstaf van prooi chemiese diskriminasie; 3) die maaginhoud van die akkedisse as 'n indikasie van hul natuurlike diëet. Waarnemings is met 'n verkyker vanaf 'n waarnemingstoring langs 'n buitemuurse kampie gemaak, terwyl dit deur 'n eenrigting glaspaneel in die geval van 'n binnemuurse opstelling gemaak is. Elke akkedis is vir 'n periode van 10 minute tydens piek-aktiwiteit dopgehou, en die tye wat dit beweeg het en nie beweeg het nie, is aangeteken. Data verkry in die binnemuurse - en buitemuurse opstellings het nie statisties van mekaar verskil nie en is saamgevoeg. BPM (0.37 ± 0.21 SD) en PTB (1.92 % ± 0.93 SD) waardes aangeteken vir C. anguina (N = 10) val binne die reeks waardes wat as kenmerkend vir sit-en-wag voeders beskou word. Nege C. anguina individue is in glas terraria gewoond gemaak om meelwurms te aanvaar wat hul aangebied is. Toe al die akkedisse die kos sonder huiwering aanvaar het, is hul vermoë getoets om tussen drie verskillende geure wat hul aangebied is in 'n ewekansige blokontwerp, te diskrimineer: prooigeur bestaande uit die reuk van meelwurms, gedistilleerde water as 'n geurlose kontrole stimulus, en reukwater as 'n skerp kontrole. Die hoeveelheid tongskiete gerig na die gegeurde wattepluisie gedurende 'n 60 s periode, is aangeteken. Geen statisties-beduidende verskille is gevind tussen die reaksies tot die drie geure nie (Kruskal-Wallis, H = 2.41, df= 2, P = 0.30). 'n Analise van die maaginhoude van 21 C. anguina individue het meestal dag-aktiewe arthropoda prooispesies onthul. Die voorkeur liggaamstemperature wat deur 12 akkedisse in 'n termiese gradiënt geselekteer is, is ses maal gemeet gedurende 'n 48 uur periode, deur van 'n termo-koppel wat in die kloaka geplaas is, gebruik te maak. Die bepaalde liggaamstemperature (N = 72) het gevariëer van 22.62 oe - 27.07 oe met 'n gemiddeld van 24.82 oe ± 2.27 SA. Die lae voorkeur liggaamstemperatuur van C. anguina mag dalk toegeskryf word aan die gekombineerde invloed van plantbedekkingskadu, hoë hoogte bo seevlak, en hoë oppervlakte-volume verhouding. Die bewegingspatrone en mikrohabitat-gebruik van C. anguina is bestudeer deur ses akkedisse in 'n buitemuurse kampie aan te hou. Die ligging van die graspolle binne die kampie is op 'n kaart aangeteken, en die posisie van elke akkedis binne in die kampie is op 17 oggende aangeteken. Verdere waarnemings is gemaak met 'n verkyker vanaf 'n waarnemingstoring terwyl die akkedisse aktief was. Alhoewel die C. anguina individue nie herhaaldelik 'n spesifieke skuilplek gebruik het nie, het hul die langer, breër graspolle as skuilplek gedurende onaktiwiteit verkies. Daar was 'n hoogs beduidende verskil tussen onderskeidelik die hoogtes (studente z-toets; P < 0.001) en die deursnitte (studente I-toets; P < 0.001) van die verkose graspolle, en die graspolle wat nie gekies is as skuilplekke nie. Hulle het gewoonlik in 'n opgerolde wyse, in die middel en na aan die bodem van die graspolle, geskuil. Daar is gevind dat C. anguina vanaf 'n verhewe posisie voed deur sy verlengde liggaam en stert in die grass te vervleg om doeltreffende gewigsverspreiding te verseker. Beweging was hoofsaaklik tot die vangaksie van prooi beperk. Vuur is 'n algemene verskynsel in fynbos en graslande, wat die hoof habitat van grasakkedisse van die genus Chamaesaura uitmaak. Met hulle slangagtige morfologie, verskil grasakkedisse drasties van ander lede van die Cordylidae, waarvan meeste rotsbewonend is. Die doelwit van hierdie studie was om te bepaal of die grasakkedisse gebruik sal maak van skuilplekke, soos gate en klipskeure binne die grashabitat, gedurende periodes van onaktiwiteit of wanneer bedreig word deur vuur. Twaalf akkedisse is verskillende skuilopsies aangebied, naamlik graspolle, klipskeure, gate en los sand. Al twaalf het verkies om in die graspolle te skuil. Toe die graspolle verwyder is, het slegs twee akkdisse die klipskeure en die gate benut, terwyl die ander 10 nie geskuil het nie. Skuilplek-seleksie wanneer bedreig word deur vuur, is getoets deur 12 akkedisse in In afskorting te plaas wat met graspolle en twee tipes skuilplekke, gate en klipskeure, voorsien is. Die gras aan die een kant van die afskorting is aan die brand gesteek en is aangehelp m.b.v. 'n hoë-spoed waaier. Voorsorgmaatreëls om die veiligheid van al die akkedisse te verseker en om in te gryp as hulle in direkte gevaar sou verkeer, is getref. In twee van die 12 gevalle het die akkedisse skuiling gesoek in die beskikbare skuilings. In die oorblywende 10 gevalle het ses akkedisse gevlug, terwyl vier deur die vlamme vasgevang was en daar ingegryp moes word. Die resultate van hierdie eksperimente, sowel as waarnemings wat in die veld gemaak is, dui daarop dat C. anguina selde van skuilopsies, anders as graspolle en restio's, gebruik maak as hulle deur vuur bedreig word. In die geval van vuur, vlug hulle deur te "swem" deur die gras. Veldwaarnemings dui ook daarop dat mortaliteit gedurende en na die vuur heelwat hoër is as in die geval van rotsbewonende gordelakkedisse. Die reproduktiewe status van volwasse wyfies (N = 85) is bepaal deur die ontwikkelingsfase van ovarium follikels te ondersoek en deur die teenwoordigheid of afwesigheid van eiers in die oviduk. Wyfies is in vier reproduktiewe kategorieë gegroepeer: pre-vitellogenies, vroeg vitellogenies, pre-ovulatories en dragtig. Testikulêre volume en saadbuisdeursnit is gemeet, en spermatogeniese aktiwiteite soos histologies vasgestel, is gebruik om die reproduktiewe siklus van die mannetjies (N = 46) te bepaal. Spermatogeniese aktiwiteit is bepaal deur van Licht (1976) se klassifikasie sisteem gebruik te maak. Die snoet-kloaak lengte (SKL) van 144 individue is gemeet en die seksuele grootte-dimorfisme (SGD) soos bepaal vir C. anguina, is gekwantifiseer deur middel van In grootte-dimorfisme-indeks (GDI). Voortplantingsaktiwiteit in die wyfies was nie gesinchroniseerd nie, en verskil dus van die normale gordelakkedissiklus met herfs/winter vitellogeniese aktiwiteit, winter/lente ovulasie en swangerskap in die volgende laat somer tot herfs. Die beduidende seisoenale verskil wat bestaan het in die testesvolume (ANOV A; F (7.22) = 3.70; P < 0.05) en die saadbuisdeursnit (ANOVA; F (10,25) = 4.90; P < 0.05), asook testis histologie, het aangedui dat C. anguina mannetjies 'n jaarlikse spermatogeniese siklus volg, beskryf as "post-nuptial". Hierdie siklus word gekenmerk deur somer/herfs spermiogenese, geassosieer met spermstoring gedurende die winter. In teenstelling met ander gordelakkedisse wat hierdie siklus volg, begin spermatogenese in C. anguina alreeds in die lente. Die gemiddelde SVL van die wyfies (109.51 mm ± 20.60 SA) was beduidend groter (Mann-Whitney; P < 0.001) as dié van die mannetjies (84.77 mm ± 9.39 SA). In Positiewe GDI van 1.29 en In GDImax van 1.40 is gemeet. Wyfie-plus dimorfisme in SKL bepaal vir C. anguina, stem ooreen met die algemene patroon waargeneem by terrestriële gordelakkedisse, maar is in kontras met mannetjie-plus dimorfisme by rotsbewonende vorme. Die langer SKL by wyfies van C. anguina kan In hoër fekunditeit fasiliteer. Dit mag dalk In oorlewingstrategie vir die species wees wat in In vuurgeteisterde omgewing voorkom, omdat suksesvolle rekolonisering deur In hoë fekunditeit aangehelp word. TREFWOORDE: Chamaesaura anguina, slangagtige liggaam; kriptiese kleuring; graslrestio habitatte; kronkel beweging; voedingsrnetode; voorkeurtemperatuur; bewegingspatrone; mikrohabitat-gebruik; vatbaarheid vir vuur; skuilplekseleksie; voortplantingsiklus; seksuele dimorfisme.

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The geometric tortoise, Psammobates geometricus, found in the Western Cape, South Africa, is one of the world's rarest tortoises. At present, it is only known from five isolated geographical areas, one being the Worcester-Tulbagh Valley. The primary aims of my study were to determine the status of geometric tortoise subpopulations along the Nl highway in the Worcester Valley, to determine the population structure of these subpopulations and, if necessary, to provide recommendations for the mitigation ofNI highway-induced impacts on geometric tortoise subpopulations along the road. All Renosterveld remnants along the Nl between Du Toitskloof and Worcester were surveyed for the presence of geometric tortoises, and tortoise density and population structure were determined for each remnant that supports tortoises. Two geometric tortoise subpopulations on opposite sides of the Nl were identified. In the larger remnant of the two, females dominated both the subadult and adult classes, whereas in the other remnant male frequency was slightly higher than female frequency for the adult class only. In both remnants, adult females were significantly larger than adult males in mean carapace length. Mean body mass for adult females and males also differed significantly in both remnants. Analysis of habitat quality showed that both remnants supporting the geometric tortoise are seriously infested by encroaching indigenous and alien plants. The barrier effect of the Nl highway can be mitigated by constructing underpasses, linking the two remnants on opposite sides of the road. Furthermore, road mortality of tortoises can be avoided by erecting tortoise proof fencing along appropriate sections of the highway in the Worcester Valley. By linking the remnants, the largest single area available to the geometric tortoise in the Worcester Valley will also be formed. An additional aim of my study was to investigate the correspondence of geometric tortoise density in individual habitat remnants to the West-to-East change in vegetation composition/characteristics occurring along the Nl in the Worcester Valley. Vegetation composition/characteristics were thus determined in all remnants also surveyed for tortoises. The West-to-East change in vegetation composition/characteristics of the study area indicates that there is a transition from Renosterveld in the West to karroid veld in the East. / AFRIKAANSE OPSOMMING: Die geometriese skilpad, Psammobates geometrieus, wat in die Wes-Kaap, Suid- Afrika, voorkom, is een van die wêreld se skaarste skilpaaie. Vandag word hierdie skilpad net nog in vyf geïsoleerde geografiese streke gekry, een van hulle die Worcester-Tulbagh Vallei. Die primêre doel van my studie was om die status van geometriese skilpad subpopulasies langs die Nl snelweg in die Worcester Vallei te ondersoek en om die populasiestruktuur van hierdie subpopulasies te bepaal. Verder was die doelook, om aanbevelings te maak oor hoe die impakte van die pad op die geometriese skilpad subpopulasies langs die Nl verminder kan word. Al die Renosterveld oorblyfsels langs die Nl tussen Du Toitskloof en Worcester, en binne die bekende gebied van die geometriese skilpad, is deursoek vir geometriese skilpaaie. Populasiedigtheid en populasiestruktuur van die skilpaaie is bepaal vir elke oorblyfsel wat skilpaaie bevat. Twee geometriese skilpad subpopulasies is gekryaan teenoorgestelde kante van die Nl. In die groter oorblyfsel, het wyfies albei die onvolwasse en volwasse klasse gedomineer. In die ander oorblyfsel is gevind dat die frekwensie van mannetjies ietwat hoër was as die frekwensie van wyfies, maar vir slegs die volwasse kategorie. Binne albei oorblyfsels is gevind dat volwassse wyfies betekenisvol groter in gemiddelde doplengte is as volwasse mannetjies. Gemiddelde liggaamsgewig het ook betekenisvol verskil tussen volwasse wyfies en mannetjies in albei oorblyfsels. 'n Analise van habitatkwaliteit het gewys dat beide oorblyfsels wat die geometriese skilpad ondersteun grootliks ingeneem is deur inheemse indringers, sowel as uitheemse plante. Die versperrings effek van die Nl snelweg kan verminder word deur duikwege te skep wat die twee ooblyfsels, op teenoorgestelde kante van die pad, verbind. Bowendien, deur 'n ondeurdringbare heining langs passende dele van die snelweg in die Worcester Vallei op te rig, sal skilpadmortaliteit vermy word. Deur oorblyfsels te verbind, salook die grootste enkele area, beskibaar aan die geometriese skilpad in die Worcester Vallei, gevorm word. 'n Addisionele doel van hierdie studie was om veranderinge in vegetasie langs 'n wes-na-oos gradient binne die studie area te korreleer met die teenwoordigheid van skilpaaie langs hierdie gradient. Vegetasie samestelling/eienskappe is dus bepaal vir elke oorblyfsel wat deursoek is vir skilpaaie. Die wes-na-oos verandering in vegetasie samestelling/eienskappe binne die studie area wys dat daar 'n oorgang van Renosterveld in die weste na 'n karooagtige veld in die ooste is.

Thesis (MDF)--Stellenbosch University, 2012. / Poverty, which was traditionally a rural phenomenon, has become one of the main drivers behind people migrating to urban areas. It is estimated that more than 50 per cent of the global population lives in cities while the current annual growth rate of cities in sub-Saharan Africa is almost double the worldwide average. The provision of food for the growing number of poor urban citizens is a major challenge, which needs to be addressed by city authorities. As most of the urbanised poor are exposed to agriculture due to their rural backgrounds, agriculture should be viewed as a possible solution to the challenge of urban food security for the urban poor. Put differently, feeding a growing urban population living in poverty will be one of the major humanitarian and political challenges of the next century. This implies that increased pressure will be put on urban agriculture for food production inside or close to cities, especially in developing countries where poor transportation infrastructure between the cities and rural areas creates problems for food supply. This research explores the significance of urban agriculture as one of the solutions to urban poverty. The aim of this research report is to critically analyse the concept of urban agriculture and how it can contribute to urban renewal and the alleviation of poverty for the urban poor. It focuses particularly on the scope, problems and challenges of urban agriculture in the high density settlements of Khayelitsha-Mitchell’s Plain in Cape Town where widespread poverty and high unemployment intensifies the need for low cost food production for poor households. The research takes into account the lessons learned in the past and looks at the role government, individuals, community organisations, NGO’s and corporate South Africa can play in expanding urban agriculture. We look at the different types of urban agriculture and the various success factors and potential pitfalls in implementing strategies of urban agriculture. This research also takes a closer look at the various problems faced by those keen to utilise urban agriculture opportunities. This research indicates that urbanisation is inevitable and has a negative impact on the poverty levels of urban citizens due to the migration of the rural poor. This is relevant to the Western Cape and in particular, to the Cape Town townships of Khayelitsha and Mitchell’s Plain, due to the accelerating migration from the rural Eastern Cape. The City of Cape Town is doing a fair amount of work in the field of urban agriculture through the Urban Agriculture Policy it adopted in 2007. However, this research concludes that urban agriculture in Africa, including South Africa, still does not receive the necessary recognition or support when compared to the developed world.

Thesis (MBA)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Childhood tuberculosis is an infectious disease that can cause serious illness and mortality in especially young children. Following contact with an infectious adult tuberculosis case, the disease is easily preventable through preventive isoniazid treatment, yet very few exposed and at-risk children currently access this healthcare service in most high-burden settings. Previous research pointed out the multifactorial and complex nature of the barriers to accessing preventive care. Specifically, the lack of a formalised recording and reporting tool, such as the universally used tuberculosis treatment registers, possibly contribute to the operational barriers of preventive care delivery to these children. The purpose of this research was to evaluate the cost-effectiveness of an isoniazid preventive treatment register tool used at community level. The study utilised previously reported data from the study population and other high-burden settings to construct a decision analysis model that included varying probabilities of isoniazid preventive treatment across three high risk age groups (<1 year of age, 1 – 2 years of age, 3 – 5 years of age), coupled with disease probabilities and associated treatment costs. The scenarios simulated included 1) the routine isoniazid preventive treatment service (3% started on treatment, 17% identified as eligible); and 2) an isoniazid preventive treatment service supported by a recording register (15% (adherent to six months of treatment) and 38% (started on IPT treatment)). In addition, two hypothetical simulations were included for 76% and 100% isoniazid preventive treatment uptake; these hypothetical simulations required additional community based healthcare worker resources in addition to the register tool. The observations from the literature indicated that more children were identified (24(17%) vs. 54(38%)) and started (4(3%, base case) vs. 54) on isoniazid preventive treatment following the implementation of the register. As expected, the mean number of tuberculosis cases prevented, increased as the proportion of eligible children that received isoniazid preventive treatment, improved; the change in the number of cases prevented per simulation showed incremental improvements which were all significantly better (p<0.01) than the base case.. The incremental cost-effectiveness ratios incurred savings for each of the scenarios simulated since the mean costs for each of the simulations were significantly less (p<0.01) than the costs associated with the base case. The current evidence suggests that the proposed isoniazid preventive treatment register tool is a cost-effective alternative to the current standard of care in place at community level for at-risk children exposed to tuberculosis. It is therefore recommended that the tool be used incrementally on a bigger scale, until such time that sufficient evidence has been generated to support widespread implementation.

Thesis (MBA)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This research focused on the experiences of female principals of co-ed high schools in the Western Cape. It investigated the path that their careers followed from the decision to become a teacher to ultimately being appointed as a principal and then having to lead the school. It further investigated the personal, organisational and social factors that were influential along the way. In addition, it probed the motivation and drive behind their career choice as well as the barriers and challenges encountered along the way. The researcher interviewed nine female principals. They were asked to tell their life story, with emphasis on their career route thus far. Key questions were asked, focusing on the motivation behind their career choice, whether they had been actively prepared for promotion and how their appointment was received. The interviews were transcribed in order to prepare them for data analysis. Any content that recorded experiences that contributed to their growth and development in teaching was coded accordingly. This produced a spectrum of codes. The codes were then placed into a diagram and grouped together, based on their meaning and implications. Identified groups included education and training, self-belief, work-life balance, mentorship, support and the stereotyping of women. The interconnectedness of the group was considered, together with their collective impact on the individual principals’ career route. The research findings indicated that the career route of the principals was determined by various factors on a personal level as well as on organisational and social levels. On a personal level, qualifications obtained and the influence of parents, family and own teachers played a role. This was critical in preparing the individual for the career path that was to follow. On an organisational level, opportunities taken, work ethic, mentorship and gender barriers were factors encountered. On a social level, the stereotyping of women and the changing family structure were factors that had to be contended with. Once appointed, it was found that the support from family, colleagues and learners contributed to their success. It emerged that the potential of these women had been identified early on in their careers and that they gained confidence when they were granted opportunities to learn and grow. To become a principal was in most cases never their intention but something that developed as they went about doing their work with commitment and diligence. Throughout, it remained a priority for them to invest in the lives of learners and the greatest joy was derived from seeing learners develop into young adults who were contributing to society.

Thesis (MDF)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The Western Cape Education Department (WCED), through the Department of Public Works (DTPW), launched the Grade R classroom programme in 2009 to increase primary school enrolment in less privileged communities. Due to the low construction contract values the programme has attracted SME contractors. These SMEs have stalled the programme by either not delivering on time or by going insolvent whilst building Grade R classrooms. This research investigated the challenges encountered by SME contractors in delivering Grade R classrooms. The objectives of the research were achieved by means of a questionnaire administered through telephonic interviews and face-to-face interviews. Thirteen contractors have taken part in the programme since 2009. All contractors who have built the classrooms in the Cape Metropole region were contacted for a telephonic interview of which 12 agreed to participate in the telephonic interviews. Descriptive statistics were used to collate and discuss the challenges reported by the contractors. The findings are similar to other studies of SME contractors. SME contractors that took part in the survey confirmed that financial factors, economic and external environment, management skills and expansion and growth factors have been affecting their businesses. The fifth factor, which is the project specific factor, had the most interesting data. Nine out of twelve contractors interviewed indicated that they were not satisfied with the grade R contract working environment. If it was not for scarcity of work, they would not tender for Grade R classrooms. Nine out of twelve contractors interviewed indicated that the DTPW and its agents hindered the successful delivery of Grade R projects through their actions. The main reasons given were the late handover of sites, incomplete construction information, unreasonable construction period, numerous specification changes and delays in processing information. What emerges from the data collected is that the DTPW needs to address the challenges highlighted in this research report. Addressing the challenges will ensure the success of the Grade R programme. This will be beneficial to both the SME contractors and the DTPW. The study also makes recommendations on how to address the challenges.

Thesis (MSc (Community Health))--University of Stellenbosch. 1995. / Please refer to full text for abstract

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Two fruit fly species, Ceratitis capitata (Wiedemann) and C. rosa (Karsch) (Diptera: Tephritidae) are known to attack deciduous fruit in the Western Cape Province of South Africa. The relative abundance of these two pests was studied in different kinds of fruit throughout the year. To facilitate field monitoring, using the immature stages, morphological differences between larval instars of C. capitata and C. rosa were investigated. Morphological characters of the larvae, such as the spiracles (anterior and posterior), mouth hooks and oral ridges were used. Many of these characters are only suitable to distinguish between the second and third instar larvae as these structures are not yet developed in the first instar larvae. Anterior spiracles were examined in terms of the number of tubules (papillae) and size or shape of the felt chambers. The number of papillae in both species was similar in the second and third instar larvae, but differed between the larvae of the two species (8-10 for C. capitata and 10-13 for C. rosa). In both species the felt chambers of the second instar larvae were narrow and elongate whilst those of the third instar larvae were broad and short. The major difference between the mouthhooks of the two tephritids was the presence of a sub-apical tooth in the third instar larva of C. rosa, being absent in the third instar of C. capitata. For the morphometric study, both laboratory-reared and field-collected specimens were examined. Measurements of the body dimensions (length and width) and various parts of the cephalopharyngeal skeleton (CPS) (mandible base, mandible length and distance between the tip and notch) were recorded in all three instars of both C. capitata and C. rosa. The data were analysed using finite mixture analysis (FMA-N1) and Levene's test was used to test for homogeneity of variances. The results of these analyses were used to estimate the frequency distributions of the larval measurements. In some cases overlaps in distributions were evident and were resolved using the same program, finite mixture analysis (FMA-N1), based on the probability of the overlapping measurements belonging to the designated instar (i.e. the one with highest probability). Determination of growth ratios suggested an approximate conformation to Dyar's rule thereby disputing the possibility of any hidden instar. However, in most cases measurements of the field samples did not conform to Dyar's rule. For the larval instars of C. capitata and C. rosa with overlapping morphological features, the morphometric approach as a distinguishing tool was demonstrated. In the field survey, the relative abundance of C. rosa at all experimental sites was very low in both orchards and adjacent vines. This suggested that this pest was either not a threat in these sites (crops) or the monitoring procedures applied, should be revised. Trap catches indicated high levels of infestation by C. capitata on some sites and low infestation levels at others. On the site with the highest population levels, activity peaks in the orchards did not co-incide with those in the adjacent vineyards. This suggested that these vineyards could be alternative hosts for fruit fly after the fruit in the orchards have been harvested. Forced oviposition (in vitro) studies indicated that Colombard (grown in Simonsvlei) was the most suitable host for survival of C. capitata. Other wine grape cultivars such as Chardonnay were also suitable for the total larval development of C. capitata. / AFRIKAANSE OPSOMMING: Twee spesies van die vrugtevlieg, Ceratitis capitata (Wiedemann) en C. rosa (Karsch) (Diptera: Tephritidae), val sagtevrugte in die Wes Kaap Provinsie van Suid- Afrika aan. Die groot hoeveelheid van hierdie twee plae op verskillende soorte vrugte is regdeur die jaar bestudeer. Voordat enige insekplaag gemonitor kan word, is dit belangrik dat die identiteit van die besondere plaag, insluitend sy onvolwasse stadiums, bekend moet wees. In hierdie studie word die morfologiese verskille tussen die larwe stadiums van C. capitata en C. rosa ondersoek. Kenmerke soos die spirakels (voor en agter), mondhake en mondriwwe is gebruik. Baie van hierdie morfologiese kenmerke kan net gebruik word om te onderskei tussen larwes in die tweede en derde stadiums omdat hierdie strukture nog nie in die eerste stadium ontwikkel is nie. Die voorste spirakels is ondersoek in terme van die aantal tubules (papillae) en die grootte en vorm van die vilt kamers. In beide spesies is die aantal papillae dieselfde vir die tweede en derde larwe stadiums, maar daar was en verskil tussen die larwes van die twee spesies (8-10 vir C. capitata en 10-13 vir C. rosa). In altwee spesies was die viIt kamers van die twee stadium larwes sma I en verleng, terwyl dit in die derde stadium larwes breed en kort was. Die hoof verskil tussen die mondhake van die twee vrugtevliee was die aanwesigheid van die subapikale tand in die derde stadium larwe van C. rosa, terwyl dit afwesig is in die derde stadium van C. capitata. Vir die morfometriese studie is voorbeelde van laboratorium geteelde vrugtevliee, asook vilee wat in die veld gevind is, ondersoek. Die liggaamsafmetings (Iengte en breedte) is gemeet asook die skelet (mandibel basis, mandibel lengte en die afstand tussen die punt en die kerf) in al drie stadiums van C. capitata en C. rosa. Die data is ontleed deur middel van eindige mengsel analise (FMA-N1) en Levene se toets is gebruik om vir homogeniteit en variansies te toets. Die resultate van die ontleding is gebruik om die frekwensie verspreiding van die larwale metings te skat. In sommige gevalle was daar oorvleueling en dit is opgelos met die gebruik van dieselfde program FMA-N1 baseer op die moontlikheid dat die metings wat oorvleuel, aan die aangeduide stadium (d.w.s die een met die hoogste waarskynlikheid) behoort. Die vasstelling van groei ratios dui aan dat dit naasteby ooreenstem met Dyar se reel en dus die moontlikheid van 'n versteekte stadium betwis. Maar in die meeste gevalle stem die veldmonsters nie ooreen met Dyar se reel nie. Die feit dat die morfometriese benadering die verrnoe het om larwale monsters met oorvleuelende morfologiese kenmerke, beteken dat dit kwalifiseer as In instrument om tussen die larwe stadiums van C. capitata en C. rosa te onderskei. Baie min C. rosa is in vrugteboorde en in nabygelee wingerde gevind. Dit dui of dat die plaag nie 'n bedreiging vir die vrugte inhou nie, of dat die monitor prosedures hersien moet word. Lokvalle dui aan dat daar 'n hoe vlak van infestasie van C. capitata in sommige gebeide is en In lae vlak in ander. Op die plek met die hoogste bevolking van vrugtevliee het die aktiwiteit in die boorde nie ooreengestem met die aktiwiteit in die nabygelee wingerde nie. Dit dui aan dat hierdie wingerde 'n alternatiewe blyplek bied aan die vrugtevliee nadat die vrugte in die boorde geoes is. Gedwonge oviposisie studies dui aan dat C. capitata die beste kan oorleef in Colombard (gekweek te Simonsvlei). Ander wyndruif kultivars is ook geskik vir die ontwikkeling tot by die laaste larwe stadium van C. capitata.

Thesis (MScAgric)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Various aspects of the biology and ecology of woolly apple aphid, Eriosoma lanigerum, were investigated, including initial galling damage caused by E. lanigerum to the roots of apple trees, the possible relationship between E. lanigerum and Xiphinema and Pratylenchus nematodes and the effectiveness of Biostart 2000® and Furfural® as possible control agents of E. lanigerum in the orchard. Preliminary root damage by first instar E. lanigerum feeding was characterized by the mechanical injury of endodermis and parenchyma tissues. Damage by second, third and fourth instar E. lanigerum was similar, but the symptoms were more pronounced. Damage caused by adults included a pronounced swelling at infected areas of the root. Cell walls hardened until the root was radially strengthened with sclerenchyma tissue and nonconducting xylem vessels while the cuticle expanded greatly through the growth of corklike cambium tissue. There was no direct relationship between the population dynamics of E. lanigerum and those of Xiphinema and Pratylenchus nematodes. The occurrence of E. lanigerum appeared to be seasonal while P. penetrans and Xiphinema numbers fluctuated erratically. Undamaged root nitrogen levels seemed to correspond with the normal root growth cycle. Nitrogen levels from galled roots were significantly lower than those of undamaged roots, probably due to E. lanigerum feeding. Soils rich in fine sand and clay sustained higher populations of E. lanigerum and Xiphinema than sandy soils. The number of E. lanigerum found in soil samples correlated well with the damage index allocated to the samples. The numbers of Xiphinema found in soil samples also correlated well with the damage index allocated to the samples according to suspected Xiphinema damage symptoms. Both Biostart 2000® and Furfural® were effective as control agents of woolly apple aphid. Furfural'Ï, a chemical waste product of the sugarcane industry, was however not as effective as Biostart 2000®, a product that includes an activator and three bacterial species, Bacillus laterosporus, B. chitinosporus and B. licheniformis. The bacteria in the Biostart 2000® treated pots could replicate themselves under suitable conditions while Furfural® dilutes with each watering. Biostart 2000® is also easier to prepare than Furfural® since the components of Biostart 2000® readily mix to form a paste easily thinned by water, whereas Furfural® is an oily substance that does not easily disperse in water. Root damage was initiated soon after E. lanigerum started feeding, however there was no apparent relationship between E. lanigerum and the nematode species. The most promising, environmentally friendly control measure was Biostart 2000®. / AFRIKAANSE OPSOMMING: Verskeie aspekte van biologie en die ekologie van die appel bloedluis, Eriosoma lanigerum, was ondersoek insluitende aanvanklike galvorming veroorsaak deur E. lanigerum op wortels van appelbome, die moontlike verwantskap tussen E. lanigerum en Xiphinema en Pratylenchus nematodes en die effektiwiteit van Biostart 2000® en Furfural® as moontlike beheeragente van E. lanigerum in die boord. Aanvanklike wortelskade deur eerste ins tar E. lanigerum voeding was gekenmerk deur die meganiese beskadiging van endodermale en parenchiem weefsel. Skade veroorsaak deur tweede, derde en vierde instar E. lanigerum was soortgelyk alhoewel die simptome meer beklemtoond was. Skade deur volwassenes het 'n meer duidelike swelsel by geïnfekteerde wortelareas ingesluit. Selwande het verhard totdat die wortel radiaalsgewys versterk was met skierenchiem weefsel en nie-geleidende xileemvate terwyl die kutikula grootliks toegeneem het deur die groei van kurkagtige kambiumweefsel. Daar was geen direkte verwantskap tussen die bevolkingsdinamika van E. lanigerum en dié van Xiphinema en Pratylenchus nematodes nie. Die voorkoms van E. lanigerum was seisoenaal terwyl P. penetrans en Xiphinema se getalle onvoorspelbaar gefluktueer het. Onbeskadigde wortel stikstofvlakke het ooreengestem met die normale wortel groeisiklus. Stikstof vlakke van galwortels was noemenswaardig laer as dié van onbeskadigde wortels, heel waarskynlik as gevolg van voeding deur E. lanigerum. Grond ryk aan fyn sand en klei het groter bevolkings van E. lanigerum en Xiphinema onderhou as sanderige gronde. Die aantal E. lanigerum in grondmonsters het goed ooreengestem met die skade indeks wat aan die monsters toegeken was. Die aantal Xiphinema in grondmonsters het ook goed ooreengestem met die beskadigingsindeks wat aan die monsters toegeken is weens vermoedelike Xiphinema skade simptome. Beide Biostart 2000® en Furfural® was effektief as beheeragente van die appelbloedluis. Furfural'", 'n afvalproduk van die suikerriet industrie, was egter minder effektief as Biostart 2000®, 'n produk bestaande uit 'n aktiveerder en drie bakterie spesies, Bacillus laterosporus, B. chitinosporus en B. licheniformis. Die bakterië in die Biostart 2000® behandelde potte kon vermeerder onder gunstige toestande terwyl Furfural® na elke besproeiing verdun het. Biostart 2000® is ook makliker om aan te maak as Furfural® aangesien die bestanddele van Biostart 2000® geredelik meng tot 'n wateroplosbare pasta, terwyl Furfural® 'n olierige vloeistofis wat moeilik 'n waterige suspensie vorm. Wortelskade het plaasgevind kort nadat E. lanigerum begin voed het, alhoewel daar geen duidelike verwantskap tussen E. lanigerum en nematode spesies voorgekom het nie. Die mees belowende omgewingsvriendelike beheermaatreël was Biostart 2000®.

Thesis (PhDAgric)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Barley leaf scald, caused by Rhynchosporium secalis, is the most important disease of barley (Hordeum vulgare) in the Western Cape province of South Africa. The disease was first reported from South Africa in 1937. The present study is the first attempt to characterise the South African R. secalis population. Topics such as pathogenesisrelated proteins, virulence spectra, variability of pathotypes, sources of variation, host resistance, breeding strategies, molecular characterisation and fungicide sensitivity are summarised in Part 1 of this dissertation. In succeeding Parts the focus is on the characteristics of the local R. secalis population regarding virulence spectrum, DNA polymorphisms, in vitro as well as in vivo fungicide sensitivity. These aspects are treated as separate entities, leading to some duplication which is unavoidable. In Part 2 the virulence spectra of 50 R. secalis isolates from a population in the. Western Cape province were determined. Twenty-one races were detected using 17 differential barley cultivars. The two most prevalent races, namely races 4 and 7 had three and four virulence genes respectively. Both race 4 and 7 were virulent on the most susceptible cultivars, namely West China, Steudelli, C.I.8618 and C.I.2226. Considering the resistance genes reported for cultivars Atlas 46, Turk, and C.I.3515 which showed no susceptible cultivar-pathogen interaction, it would appear that the Rh- Rh3-Rh4 complex is primarily involved in conferring resistance to the local R. secalis isolates. A total of 20 races (47 isolates) characterised in Part 2 were selected for further characterisation by means of DNA fingerprinting. In Part 3 an anonymous multilocus DNA probe was used to characterise the genotypic structure of these isolates by means of RFLP analysis. No correlation between any particular fingerprint pattern, race, district, field or lesion was found. The two most prevalent races, 4 and 7, did not share the same genotypes, even when isolated from the same field or lesion. The genotypic diversity of the isolates studied was 46.5% of the theoretical maximum diversity. The high level of genotypic variation observed in the South African R. secalis population resembled the genotypic diversity observed in other cereal pathogens with known sexual structures. Although no teleomorph has yet been observed, these data suggest that sexual recombination may operate within the local population of R. secalis. In South Africa barley scald is primarily controlled by means of fungicides. The continued use of fungicides on cereal crops results in the build-up of fungicide resistance in the population, which could lower the efficacy of these compounds. These aspects were investigated in Part 4, where isolates (collected during 1993 to 1995) were evaluated in vitro for sensitivity to triadimenol, tebuconazole, flusilazole and propiconazole. The sensitivity fluctuated but in 1995 isolates were significantly less sensitive towards triadimenol than in the previous two years. In a second experiment, isolates collected from two fields with a 5-6 year-history of triadimenol seed treatments and tebuconazole applications, were evaluated for their fungicide sensitivity. A significant positive correlation was observed between tebuconazole and triadimenol sensitivity among,R. secalis populations from these fields. However, such a correlation was not found within the R. secalis population collected during 1993-1995 where shorter crop rotation patterns and a range of fungicides was applied. In a third experiment, the fungicide sensitivity of local R. secalis isolates was evaluated towards two new triazole fungicides, namely bromuconazole and triticonazole. Correlation coefficients observed between these new triazoles and those previously applied in South Africa were not significantly positive. The lack of significant cross-resistance has important practical implications regarding the management of fungicide resistance. In Part 5, isolates with different minimum inhibitory concentration (MIC) towards tebuconazole in vitro (1, 3 and 10 ug/ml) were compared in vivo. The aim of this study was to determine how MIC values would influence virulence (leaf area affected) and sporulation. Results indicated that all isolates were equally fit to induce lesions and sporulate in the absence of tebuconazole. Thus no fitness cost was associated with the degree of tebuconazole sensitivity in the present study. All R. secalis isolates were able to induce lesions on tebuconazole treated leaves, but differed significantly with respect to the percentage leaf area affected. Isolates, least sensitive (MIC = 10 ug/rnl) towards tebuconazole were more adapted on tebuconazole treated leaves, being able to repeatedly cause larger lesions than sensitive R. secalis isolates (MIC = 1 ug/rnl), Sporulation was not significantly different between isolates on lesions of untreated or tebuconazole treated leaves. Larger leaf areas affected and adequate sporulation suggest that a less sensitive population would result in more disease in tebuconazole treated fields. In conclusion, this study revealed the variability associated with the South African R. secalis population regarding virulence spectrum and genotypic structure. The data in this study suggest that it is likely that the local population will easily adapt to newly introduced, single gene resistance. For more durable resistance, higher levels of quantitative resistance should be introduced. This type of resistance is, however, more difficult to identify and incorporate than single gene resistance. Consequently, barley scald control will remain dependent on the efficacy of fungicide applications. Furthermore, the lack of cross-resistance and low frequency of resistant isolates indicates a low risk for the development of fungicide resistance in the local R. secalis population. Other factors such as current crop rotation practices and the range of fungicides being ~pplied also contribute to this low risk level. However, the status of these factors can change over time. The in vivo tebuconazole sensitivity study has indicated that a resistant field population of R. secalis may be able to build-up. It is, therefore, necessary to monitor the fungicide sensitivity of R. secalis isolates at timely intervals with view to successful barley cultivation in the future. / AFRIKAANSE OPSOMMING: Blaarvlek op gars (Hordeum vulgare), veroorsaak deur Rhynchosporium secalis, is die belangrikste siekte van gars in die Wes-Kaap provinsie van Suid-Afrika. Die voorkoms van R. secalis op gars is in Suid-Afrika vir die eertse keer in 1937 gerapporteer. Hierdie studie is die eerste poging tot karakterisering van die plaaslike R. secalis-populasie. Aspekte soos proteïene betrokke by patogenese, virulensiespektra, variabiliteit van patotipes, bronne van variasie, gasheerweerstand, teeltprogramme, molekulêre karakterisering en swamdodersensitiwiteit word in Deel I van die tesis opgesom. In die daaropvolgende gedeelte is die fokus op die karakterisering van die R. secalis-populasie en behels DNA karakterisering, virulensiespektrum, en swamdodersensitiwiteit in vitro asook in vivo. .. In Deel 2 is die virulensiespektra van 50 R. secalis isolate van 'n populasie in die. Wes-Kaap geëvalueer teenoor 17 differensiëel weerstandbiedende gars kultivars en hieruit is 21 rasse geïdentifiseer. Die twee mees algemene rasse (rasse 4 en 7), met onderskeidelik drie en vier virulensie gene, het virulent vertoon teenoor die mees vatbare kultivars soos West China, Steudelli, C.I.8618 en C.I.2226. Geen vatbare kultivar-patogeen interaksies is met kultivars Atlas 46, Turk en C.I.3515, wat al drie die Rh-Rh3-Rh4 kompleks dra, gevind nie. Dit wil dus voorkom asof hierdie genekompleks effektiewe gasheerweerstand teen die plaaslike R. secalis isolate kan bied. 'n Totaal van 20 rasse (47 isolate), gekarakteriseer in Deel 2, is geselekteer vir verdere karakterisering met behulp van DNA bandpatrone. In Deel 3 is 'n anonieme multilokus DNA peiler gebruik om deur middel van RFLP analise die genotipiese struktuur van hierdie R. secalis-isolate te bepaal. Geen assosiasie is gevind tussen DNA bandpatroon en ras, distrik, garsland of letsel nie. Die twee rasse (4 en 7) wat mees algemeen voorkom, het nie dieselfde bandpatroon vertoon nie, ook nie dié afkomstig vanuit dieselfde garsland of letsel nie. Die genotipiese diversiteit van isolate was 46.5% van die teoretiese maksimum diversiteit. Die hoë vlak van variasie waargeneem in die R. secalis populasie is soortgelyk aan variasie waargeneem in ander graanpatogene wat oor 'n geslagtelike stadium in die lewenssiklus beskik. Alhoewel geen geslagtelike stadium tot dusver geidentifiseer is nie, dui die vlak van variasie daarop dat geslagtelike rekombinasie moontlik wel plaasvind binne die plaaslike R. secalis populasie. In Suid-Afrika word blaarvlek op gars primêr deur swamdoders beheer. Die toenemende gebruik van swamdoders op graangewasse veroorsaak moontlik 'n opbou van swamdoderweerstand in die populasie. Dit kan die effektiwiteit van swamdoders verlaag. Hierdie veronderstelling is in Deel 4 ondersoek, waar die sensitiwiteit van isolate in vitro teenoor triadimenol, tebukonasool, flusilasool en propikonasool geëvalueer is. Die triasooi sensitiwiteit van R. secalis isolate wat gedurende die 1993- 1995 seisoen versamel is het gewissel en slegs vir triadimenol was daar 'n tendens na meer weerstandbiedenheid. 'n Swamdoder-evaluasie is in 'n aparte eksperiment op isolate gedoen wat versamel is vanaf twee garslande met 'n 5-6 jaar geskiedenis van triadimenol saadbehandelings en tebukonasool bespuitings. 'n Betekenisvolle positiewe korrelasie is waaJ~geneem tussen tebukonasool en triadimenol sensitiwiteit in R. secalis isolate afkomstig vanaf hierdie twee garslande. 'n Soortgelyke korrelasie is egter nie gevind in die populasie wat gedurende die 1993-1995 seisoene versamel IS me. Laasgenoemde kan moontlik toegeskryf word aan korter wisselboupatrone en die toediening van 'n verskeidenheid van swamdoders. In 'n derde eksperiment is die sensitiwiteit van plaaslike R. secalis isolate teenoor twee nuwe triasole, naamlik bromukonasool en tritikonasool getoets. Die korrelasie waargeneem tussen die twee nuwe triasole en triasooi swamdoders reeds voorheen in gebruik in die Wes-Kaap was me betekenisvol positief me. Die gebrek aan betekenisvolle kruisweerstandbiedendheid het belangrike praktiese implikasies vir die bestuur van swamdoder -weerstandbiedendheid. In Deel 5 is isolate met wisselende minimum inhiberende konsentrasies (MIKs) teenoor tebukonasool in vitro (1, 3 en 10 ug/ml) en in vivo vergelyk. Die doel van hierdie studie was om te bepaal hoe wisselende MIK-waardes virulensie (blaaroppervlakte geïnfekteer) en sporulasie sal beïnvloed. Resultate dui daarop dat alle R. secalis isolate in hierdie studie ewe fiks was om, in die afwesigheid van tebukonasool, letsels te induseer en te sporuleer. Die bevinding is dat die verlies in fiksheid nie geassosieer is met die mate van tebukonasool weerstand nie. Alle R. secalis isolate het die vermoë gehad om letsels op tebukonasool-behandelde blare te veroorsaak maar het betekenisvol verskil ten opsigte van die blaaroppervlakte geaffekteer. Isolate wat minder sensitief (MIK = 10 ug/rnl) teenoor tebukonasool in vitro is, het meer aangepastheid op tebukonasool-behandelde blare getoon. Gevolglik het hierdie isolate herhaaldelik meer letsels veroorsaak as sensitiewe isolate (MIK = 1 ug/ml), Sporulasie het nie betekenisvol verskil tussen isolate vanaf letsels op ondehandelde of tebukonsoolbehandelde blare nie. Hierdie resultate dui egter daarop dat 'n minder sensitiewe populasie tot meer siektevoorkoms in tebukonasool-bespuite lande kan lei. Die studie het die veranderlike karakter van die Suid-Afrikaanse R. secalispopulasie aangaande virulensiespektrum en genotipiese struktuur blootgelê. Dit is dus baie moontlik dat die R. secalis-populasie maklik sal aanpas by teelmateriaal met nuwe enkelgeen-weerstand. Vir volgehoue gasheerweerstand is dit egter nodig dat hoër vlakke van kwantitatiewe weerstand ingeteel moet word. In die praktyk is hierdie tipe weerstand egter baie moeiliker om te identifiseer en by nuwe teelmateriaal in te sluit as in die geval van enkelgeen-weerstand, Dit bring mee dat blaarvlekbeheer afhanklik bly van swamdodertoedienings as beheermaatreël. Die resultate van hierdie studie dui daarop dat daar tans 'n lae risiko vir die ontwikkeling van swamdoderweerstand in die plaaslike populasie is, as gevolg van die afwesigheid van kruisweerstandbiedendheid en die lae voorkoms van weerstandbiediende isolate. Ander faktore soos die wisselboustelsels wat toegepas word en die verskeidenheid van swamdoders toegedien dra ook daartoe by. Ten spyte hiervan kan die status van hierdie faktore egter oor tyd verander. Die in vivo tebukonasool studie het daarop gedui dat 'n weerstandbiedende veldpopulasie van R. secalis die potensiaal het om te vermeerder. Gevolglik is die tydige monitering van swamdodersenisitiwiteit van R. secalis isolate noodsaaklik om 'n volhoubare garsproduksie te verseker.