Isolation, Identification, and Characterization of Some Fungal Infectious Agents of Cassava in South West Ethiopia

Abstract

Cassava (Manihot esculenta) is a dicotyledonous perennial woody shrub with an edible starchy root, belonging to the botanical family Euphorbiaceous. Apart from its use as human food, cassava products also are popular in international trade under different forms. The crop is economically and nutritionally useful in south western parts of Ethiopia. There is scarcity of information so far on the fungal diseases of cassava in Ethiopia. This study was, therefore, initiated to isolate, identify and characterize some fungal infectious agents of cassava in south western parts of Ethiopia. Samples from organs and the plant tissues were first washed in sterile distilled water and surface sterilized in 1% Sodium hypochloride for one minute and then after in 70% alcohol each for one minute. This was followed by rinsing the plant material in sterile distilled water and allowed to dry on sterile tissue paper. The dried tissues were then cultivated on to PDA and incubated at 25⁰C. Streptomycin sulphate antibiotic 0.05mg/ml was used to avoid the bacterial contamination. Water agar (WA) media was used for sporulation and to have mono-conidial isolates of fungi. Mono-conidial isolates of the recovered fungi were stored on PDA slants in the refrigerator at 4⁰C for further studies. Eleven isolates were obtained from samples of five locations. However, among these, only six fungal isolates induced pathogenicity on healthy cassava seedlings and leaves. These fungal isolates which grew on glass slide were identified to the genus level by using light microscope as Cephalosporium AAUCF01, Fusarium AAUCF02, Hendersonula AAUCF03, Aspergillus AAUCF04, Penicillum AAUCF05 and Botrytis AAUCF06. The distribution, infection and severity of Fusarium AAUCF02 and Cephalosporium AAUCF01 were more than the other pathogens.

Key words/phrases: - Production, Pathogenicity, Fungal diseases, Cassava, Bio-control