Browsing by Author "Phillips, Shivaani."

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Evaluation of growth media parameters for the cultivation of selected biological control agents.
(2002) Phillips, Shivaani.; Laing, Mark Delmege.; Hunter, Charles Haig.
Trichoderma harzianum kmd, Gliocladium virens MMI and Colletotrichum gloeosporioides C6 are potential biological control agents. Trichoderma harzianum kmd and and G. virens MMI have been shown to have excellent growth stimulation and disease suppressive characteristics by the Biocontrol for Africa team of researchers at the University of Natal, Pietermaritzburg. Colletotrichum gloeosporioides C6 has been shown to have effective control of the invasive weed, Hakea sericea (Shrad.). The aim of this dissertation was to establish a method which was most effective for the mass production of the biological control agents (BCAs). Various parameters and the impact of carbon-to-nitrogen and total organic carbon (TOC) on the growth of the BCAs were investigated. Fingerprinting and detection of mutations between strains of Colletotrichum gloeosporioides C6 of different ages were attempted using AFLPs for patenting purposes. Pine shavings and molasses were used in the semi-solid fermentation of T harzianum kmd, G. virens MMI and C. gloeosporioides C6. A 70% (v/v) ethanol soak was the most effective pretreatment in the removal of resin off the pine shavings as well as eradication of contamination. Parameters tested were pH, C:N ratios and TOCs. The optimal pH range for T harzianum kmd and C. gloeosporioides C6 was between pH 6.5 and 7. The optimal pH for G. virens MMI was pH6. Various C:N ratios and TOCs produced highly significant differences in spore yield and mycelial biomass (P