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Augmentation of Aphytis melinus DeBach (Hymenoptera: Aphelinidae) for the control of California red scale Aonidiella aurantii Maskell (Hemiptera: Diaspididae) on citrus
Get PDFAphytis lingnanensis was reared and tested in South Africa in the early 2000s for augmentation against red scale on citrus and was found to be ineffective. Aphytis melinus is now commercially available and it is important that the efficacy of augmentation thereof on red scale is determined locally. Field trials, fitness assessments and molecular identification on A. melinus from two insectaries were done. Field trials was done in seven, five and six pairs of comparable release and control orchards across the Eastern and Western Cape during the seasons of 2019/2020, 2020/2021 and 2021/2022 respectively. Red scale infestation was monitored and a sample of 20 infested fruit from each orchard was randomly collected every four weeks. Aphytis spp. responsible for parasitism were identified and the percentage parasitism recorded. Results of this study of field trials suggest that the augmentation of A. melinus did not significantly increase the level of parasitism above that of the untreated control. Five repetitions with six replicates of flight and longevity tests were performed with wasps from each insectary. Wasps in the longevity test from two insectaries were kept at 23 °C and 65% RH with honey. Flight tests were performed in tubes of 16 by 30 cm, with a light above a clear, sticky ceiling at 23 °C and 65% RH. On average in five replicates, 65%, 33% and 17% A. melinus wasps were alive on day one, five and 10 respectively. The overall sex ratio was 1.58 for females to males, but 1.05, 2.19 and 2.66 for non-flyers, non-crawlers, crawlers, and flyers respectively. In flight tests for both insectaries combined, only 36.97% of wasps could initiate flight in 24 h while 56.96% remained on the tube floor, and 6.05% attempted to crawl upwards. No significant differences in flight performance were recorded between the two insectaries. Wasps from the local insectary lived significantly longer during the longevity tests but were shorter in transit than wasps from the overseas insectary. COI genes were sequenced and compared against Genbank sequences using BLAST. Molecular identifications did not confirm morphological identifications for all species, indicating unexpected genetic complexity.Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 202
The intellectual responsibility of women in challenging domination and abuse: the analysis of the isiXhosa sampled texts authored by women (1976-2015)
Get PDFUphando luza kuqwalasela ingqiqo yamanina kuxanduva lokusiphula neengcambu ugonyamelo nokuxhatshazwa kwawo ngamadoda. Ingxoxo iza kugxila kubabhali abangamanina beencwadi zesiXhosa ezicatshulweyo kolu phando, nalapho kuqwalaselwa indlela ababazoba ngayo abalinganiswa babo abangamanina. Kule ngxoxo kuqwalaselwa indlela ababhali abangamanina abafana noBelebesi (1976), Dazela (1988), Magadla (1992) Madolo (1998), Mayosi (2003), Magqashela (2006) kunye noBuzani (2015) abathe babazoba ngayo abalinganiswa abangamanina kwiincwadi zesiXhosa ezicatshuliweyo. Oku kukutyhila ubukrelekrele bababhali ekusebenziseni uncwadi ukuzisa izisombululo kwimingeni ajamelene nayo amanina efana nogonyamelo kunye noxhatshwazo. Obu bukrelekrele baba babhali bujongwa ngokweembali ezimbini, imbali yaphambi kozuzo lwenkululeko emva kongenelelo lobuKoloniyali kunye neyasemva kozuzo lwenkululeko yaseMzantsi Afrika. Iincwadi ezikhethiweyo zibhalwe phakathi kweminyaka ye-1976 ukuya kwiminyaka yama-2015. Uphando luya kujonga ukuba lungaba lukhona utshintsho kusini na kwindlela la manina ababazoba ngayo abalinganiswa ngokwezi mbali zahlukileyo kananjalo naxa bezotywa ngababhali abangamadoda. Uphando luya kutyhila kananjalo imixholo nemixholwana abayikhethayo nedlulisa iimvakalelo zabo bengamanina kumbandela wogonyamelo olukhatshwa yipatriyakhi kunye noxhatshazo abalufumana kumadoda. Xa kuphendlwa le mixholo yaba babhali bahlukileyo baneemvelaphi ezahlukileyo ngokwemontlalo bebhala ngokwamaxesha okanye iimbhali ezahlukileyo, kuya kucaca ukuba amava abo ayafana nokuba linina okanye ibhinqa. Loo mava abo anele ukuba bajikeleze kwimixholo ebizwa ngokuba yifeminist themes nakubeni izimbo zabo zokubhala zahlukile nje. Injongo kukubonisa ukuba nangona amanina aphila phantsi kweemeko neemontlalo ezahlukileyo nje, iinzima neentlungu zawo azisombulula ngendlela efanayo ngokusebenzisa usiba. Le ngxoxo ikhatshwa ziithiyori ezifana nefemayinizimu, ngakumbi ifemayinizimu yaseAfrika kunye kunye nangokoMzantsi Afrika iquka iMotherism kunye nenkcubeko ephehlelelwe phantsi kwePatriyakhi. Ezi thiyori ziludondolo lokuphendla nokuhlalutya ezi ncwadi zikhethiweyo zesiXhosa ukuze sicacelwe yeyona ndima idlalwa ngamanina kuluntu nanjengoko sisazi ukuba apha eMzantsi Afrika adlale eyona ndima yokuncedisa ekuziseni utshintsho kwimibandela yengcinezelo nasekuzuzweni kwenkululeko. Yiyo loo nto kufuneka nawo abonakale exhamla ngokulinganayo namadoda kwinkululeko ayisebenzeleyo ngokususa ugonyamelo, uxhatshazo nokubulawa kwawo ngamadoda.Thesis (PhD) -- Humanities, School of Languages and Literatures, 202
Social justice implications of the language of the court judgment genre and its development in pre- and post-independence Zimbabwe
No full textAccess restricted. Expected release in 2026.Thesis (PhD) -- Humanities, Linguistics and Applied Language Studies, 202
“COVID-19 made me a single parent”: an interpretative phenomenological analysis of a woman’s perinatal experiences during the COVID-19 pandemic
Get PDFThe COVID-19 pandemic resulted in unprecedented challenges across various aspects of life. In particular, pregnant women encountered unique challenges and circumstances that necessitated adaptation to the experience of the perinatal period1 Satyanarayana et al., (2011). A considerable amount of research has been conducted regarding women's experience of the perinatal period during COVID-19, especially in first world countries. However, inadequate research has been done in the South African context and specifically, there is a lack of qualitative research providing thick descriptions of experience. The analysis describes three master themes supported by subordinate themes. The main themes are (1) A sense of loss and change, (2) Managing COVID-19 and its regulations during the perinatal period, and (3) Glimmers of hope and desirable aftermaths. The study’s findings expand and support the growing literature of women’s experiences on the perinatal period during the COVID-19 pandemic.Thesis (MA) -- Faculty of Humanities, Psychology, 202
Managing releases of Anagyrus vladimiri (Triapitsyn) to augment biocontrol of the citrus mealybug Planococcus citri (Risso) in South African citrus orchards
Get PDFIn May 2019, South Korean inspectors rejected numerous grapefruit consignments from Letsitele, Hoedspruit and Onderberg in South Arica, because of live mealybug found on fruit. Growers expressed deep concern as mealybug management to a phytosanitary level was almost unattainable. Regular spray interventions for control of citrus black spot fungus, Phyllosticta citricarpa, and citrus thrips, Scirtothrips aurantii, cause repercussions in mealybug populations because they undermine the naturally occurring biocontrol complex. As part of an Integrated Pest Management (IPM) strategy, release of commercially produced parasitoids is common practice, to augment the naturally occurring beneficial insect populations. Prior knowledge of the harmful effects of insecticides on parasitoids is essential to IPM planning and the success of the biocontrol component in such a programme. Timing of augmentative releases to coincide with the phenology of citrus and the mealybug pest is also considered important for the successful establishment and control. Consequently, field trials were conducted to compare efficacy of early vs. late releases of Anagyrus vladimiri (Triapitsyn), an effective parasitoid of the citrus mealybug, Planococcus citri (Risso). Semi-field bioassays were conducted concurrently to determine the impact of various thripicides on A. vladimiri. The impact of sulfoxaflor, spinetoram, spirotetramat and prothiofos were rated harmless, as A. vladimiri mortality was lower than 25% after coming into contact with aged residues between 7 and 14 days old. October and November releases of A. vladimiri resulted in early parasitism and lowered peak-infestation of mealybug. January releases are possibly too late in grapefruit and lemon, open field, orchards, considering parasitism by A. vladimiri peaked in February. In mandarin orchards under net, percentage parasitism of 3rd instar mealybug increased a month later. Notably, at harvest, the difference in efficacy between treatments was not clear. This could be explained by high levels of natural parasitism observed in the treated and untreated orchards, which emphasises the importance of conservation biocontrol. In a second season, the proportion of hyperparasitoids captured (61%) from samples of mealybug-infested fruit was larger than the proportion of primary parasitoids, Anagyrus vladimiri, Coccidoxenoides perminutus (Girault) and Leptomastix dactylopii (Howard) (39%), which was far lower than the captures of eclosing primary parasitoids the previous season, which was 60%. The new discovery of Pseudaphycus sp. in citrus orchards in South Africa could be a key in explaining the uncontrollable levels of mealybug experienced and has drawn attention to a need for further understanding of ecological factors that influence biological control in citrus.Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 202
Tradition and change in the Imfene dance of the amaMpondo in the Ntabankulu district of the Eastern Cape province
No full textAccess restricted. Expected release 2025.Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 202
The impact of influencer characteristics on parasocial relationships and purchase intentions
No full textAccess restricted. Expected release in 2026.Thesis (MCom) -- Faculty of Commerce, Management, 202
Factors that influence the adoption and implementation of sustainable procurement: a case of a South African public university
Get PDFClimate change and resource scarcity have become some of the world's most critical problems and are among the most significant megatrends influencing world leaders' agendas in decision- making (Rothkopf & Casey, 2014; International Social Security Association, 2014). Sustainable procurement has been identified as one of the strategic tools that can resolve these issues to help the world move towards a more sustainable and resilient future (World Bank, 2019). Through sustainable procurement practices, organisations can meet their demand and supply of goods and services while minimising environmental harm, maximising financial returns, and enhancing socioeconomic status (Villena & Gioa, 2020; Bonnemaison, Eldandsson, Ibach & Spiller, 2021). This qualitative research used an Eastern Cape-based higher education institution in South Africa as a case study to investigate factors that influence adopting and implementing sustainable procurement, with resilience as a theoretical foundation, in higher education. The research obtained approval from the participating university as a gatekeeper for the study; it began by drafting a research proposal and securing ethical clearance from Rhodes University. Semi-structured interviews were used with seven higher education procurement staff members to get the data working in procurement in higher education. The findings from the study revealed that managerial support and knowledge of sustainable procurement were determining factors for whether or not a university developed and implemented a strategy for sustainable procurement.Secondly, the participants mostly cited barriers as inadequate financial resources resulting in limitations for the university, therefore partially implementing sustainable practices. Thirdly, the data revealed that university staff in procurement had a basic understanding of sustainable procurement.Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 202
Issues in language acquisition planning in Zimbabwe: the case of Ndebele within the primary education system
Get PDFThis thesis discusses pertinent language issues within the primary school system in Zimbabwe in view of complaints (over many years) of communities in the two Matabeleland provinces and Bulawayo about high failure rates of learners in the final grade 7 examinations. It also interrogates the government’s commitment to the development of indigenous languages in the primary school system, particularly in the three provinces mentioned above as mirrored in the 2013 constitution of the country. The study conducted traces the language trends exhibited currently back to their beginnings during the colonial era in language planning by the government and the policies that informed such planning. What obtains on the ground seems to be violating the principles behind the declaration of the International Mother Language Day (30C/62) proclaimed by the General Conference of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in November 1999. On 16 May 2007 the United Nations General Assembly, in its resolution A/RES/61/266, called upon Member States (Zimbabwe included) "to promote the preservation and protection of all languages used by peoples of the world". The amended education act of 2006 states that in Zimbabwe’s primary schools early learning must be done through mother tongue instruction then switch to English in grade 4 upwards. As a first step of a child’s academic life, the lower primary education needs to be conducted in the child’s mother tongue to bridge the gap between the child’s home environment and the new school environment as well as to reduce culture shock associated with the sudden introduction of a new language. Studies, such as those done by Noormohamadi, (2008) and Mackenzie, (2013) have shown that children tend to understand better if they are taught in their mother tongue. In this thesis I seek to establish if the teaching of Ndebele at primary school reveals the socio-cultural ideology (awareness of circumstances surrounding individuals and how their behaviours are affected, specifically by their surroundings, social and cultural factors) and political ideology (thinking structures about the way policies should be run) underpinning language planning in Zimbabwe. It is my observation and argument that the Education Act proclaims what has not been practised on the ground through teacher training and deployment practices. To establish if the teaching of Ndebele at primary school reveals the socio-cultural and political ideologies underpinning language planning in Zimbabwe, I carried out research in Matabeleland South, Bulawayo and Matabeleland North provinces covering a total of 27 schools, 27 heads of school and 135 teachers. The research’s main aims were to find out if Ndebele was taught at school, by who and using what materials. It should be noted that mother tongue, in learning, acts as a basis of interpretation of subsequent concepts. When a child is learning new concepts or words in the second language, he or she first searches the equivalent in his or her mother tongue. If the primary language has not been developed well enough to have such equivalents, such a child is likely to have problems in forming new concepts in the second language. The role of language in meaning, therefore, is a variable that depends on the socio-geographical location of the languages and their speakers. The research established that, indigenous languages, Ndebele included, are not developed by the government through financial support for teaching material production and qualified teacher deployment. Instead, it was discovered that in Matabeleland there are some learners at primary school who are taught by a Shona-speaking teacher who cannot communicate properly with the learners. It should be remembered that a primary language is used by a child as the foundation to learn the basic concepts in his or her own language and to give him or her freedom to express himself or herself without the inhibitions imposed by an insufficient mastery of the medium of instruction. As a way of concluding the research I found it necessary that the use of mother tongue by learners at lower grades of primary school be strengthened through the deployment of teachers who can teach Ndebele properly because it provides a strong foundation for further education. Using the mother tongue, students learn to think, communicate and acquire an intuitive understanding of grammar. The mother tongue is; therefore, the greatest asset and vital tool people use to acquire new concepts.Thesis (PhD) -- Faculty of Humanities, School of Languages and Literatures, 202
A comparative analysis of land, labour and gender in a communal area and fast track farm in Zvimba Rural District, Zimbabwe
Get PDFThis thesis provides a comparative analysis of gender, land, and labour between two different types of farming sites in rural Zimbabwe, namely long-established communal areas and the more recent Al fast track land reform resettlement areas. More specifically, the focus is on Kanzou Village and Stratford fast track resettlement farm respectively, located in Zvimba District in Mashonaland West Province. The study focuses on the period from the year 2000, the year in which the fast track resettlement programme was launched by the government. The thesis examines in particular the status and experience of women with regard to land acquisition, access and security as well as the division of labour (including assets, inputs and labour-time) in the spheres of production (i.e., agriculture) and social reproduction (i.e., the domestic sphere). This includes highlighting the power relations existing between men and women in both spheres, in the light of prevailing systems of patriarchy. Analytically, the thesis is framed in terms of feminism, drawing upon the complementary insights of Third World feminism and socialist feminism. In seeking to capture the perspectives and practices of men and women in the two sites, the fieldwork for the study entails a qualitative methodology. The findings of the research demonstrate the existence and relevance of patriarchal systems with respect to land and labour in Kanzou Village and Stratford fast track farm, with key commonalities appearing across the two sites with reference to the multiple ways in which women are disadvantaged and disempowered. Therefore, gender bias and inequality in land and labour are exhibited by the fact that men have, for instance, easier access to land, less involvement in labouring activities, control over a higher proportion of household income and a disproportionate level of power in the household. At the same time, there are certain differences between Kanzou Village and Stratford fast track farm around questions of gender, land and labour, but these are differences in degree rather than kind. Perhaps more important in explaining the differences between the two sites, and indeed differences within each site, are other variables. These variables include marital status, form or marriage (for example, customary or civil marriages), age and gender. By considering these variables as well, the thesis shows the importance of unpacking the notion of ‘woman’ to reveal the variegated and differential experiences of different categories of women in rural Zimbabwe.Thesis (PhD) -- Faculty of Humanities, Sociology, 202