Browsing by Author "Chifamba, Olive"

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    Effect of Method of Inoculation, Moisture and Seedling Age on Foliar Anthracnose Development in Two Varieties of Sorghum bicolar (Kadoma 332 and Marapansi)
    (Academy Science Journals, 2010-10-26) Dube, S.; Chifamba, Olive; Mbanga, Joshua
    The infection efficiency of Colletotrichum sublineolum was determined on two Sorghum bicolar varieties Kadoma 332 and Marapansi. In all situations Marapansi was resistant to Colletotrichum sublineolum whereas K332 was susceptible to varying degrees in different situations. Pathological development progressed as follows; a few circular spots appeared after inoculation and their number increased progressively. Initially they developed into circular well defined elliptical lesions ranging from tan to brown in colour with straw coloured centers which were spotted with minute black specks. Extensive areas of dry tissue were observed leading to the death of mainly the basal leaves as the infected areas coalesced. Bagging showed improvement for the onset and development of the disease with the application of conidial spores being more effective for disease onset than infected leaf powder for both bagged and none bagged plants. Effect of the age of the plant on susceptibility was investigated. This involved inoculation of the plants at three different growth stages. These were the seedling stage, growth stage 3 and growth stage 5 (the booting stage). Development of anthracnose in K332 was optimized at Stage 5 followed by stage 3 then stage one. Increasing the frequency of bagging above once every other day did not improve chances of onset and development of anthracnose on the tested plants. In vitro experiments to study the mode of entry and proliferation of the fungus and its optimal temperature of growth revealed that spores germinated within 24 hours and 27 o C was found to be the optimal temperature for fungal development.