The effect of Media and Light Regimes on Cultural and Morphological Characteristics and Sporulation of Phaeoisariopsis Griseola Deighton

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Date
1994
Authors
Mwang'ombe, A.W.
Karanja, T.W.
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Abstract
Studies were conducted to optimize the medium and light regime for culturing an isolate of Phaeoisariopsis griseola obtained from cv. Kosecoco-GLP-2 bean (Phaseolus vulgaris L.) field in Kenya. Conidial variation in septation and shape for this fungus was also investigated. Conidia were borne at the tip of the conidiophore, they were brown in colour, cylindrical to spindle in shape (average 17-95 11 long by 7-24 11 wide) but sometimes slightly curved yet not constricted. A few conidia were Y -shaped. From zero to eleven septa were observed per conidium, with an average of two to three. Pathogenicity tests using this isolate produced typical angular leaf spot symptoms on beans cv. Rosecoco-GLP-2. The fastest hyphal growth at 21-24°C occurred on potato yeast dextrose agar (PYDA) where the mycelia were fluffy and raised, and mainly grey in colour. The most abundant sporulation of P. griseola occurred on bean leaf dextrose agar (BLDA) where the mycelium was compact and mostly dark grey to black in colour. Light regime had little effect on mycelial growth, but sporulation was best in continuous darkness. Therefore, for cultures promoting inoculum production, BLDA and darkness were the most ideal conditions.
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East African Agricultural And Forestry Journal, 59 (No. 3), pp. 241-251
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