Intrinsic and Extrinsic Factors Affecting Growth and Sporulation of Corticium koleroga (Cke) Hoehnel

A numerous production constraints have been affecting coffee production and productivity. Among the constraints, coffee diseases attacking fruits, leaves, stems and roots that reducing coffee yield and marketability are economically important across the country. Coffee thread blight disease considered as a minor for 40 years in Ethiopia is currently emerging as a significant bottleneck to the sector. Recently, the occurrence and significant damage due to this disease have been frequently reported from different coffee production areas. However, there is the lack of profiled information on intrinsic and extrinsic character of the pathogen. Hence, this study was initiated to determine the effect of temperature and artificial media on the growth and sporulation of C. koleroga. Collected sample from Metu sub-center have been isolated and purified. Then after, purified isolate was characterized on five different artificial media namely PDA, MEA, Sabouraud, yeast and Czapeck and three temperatures (20, 25 and 30°C) ranges for growth and sporulation. The result revealed, there was a significant difference (P<0.001) among media and temperature ranges in the sporulation and radial growth rate of the pathogen. The fastest radial growth 3.57 and 3.51mm/day was recorded from PDA and Sabouraud media when incubated at 25°C, respectively. Whereas, the lowest growth rate was observed on yeast extract agar. On the other hand, the highest spore amount (116 spores/ml) was recorded from Sabouraud medium followed by potato dextrose agar and Yeast extract agar media at 25°C. The study confirmed that the three media (Sabouraud, Yeast extract agar and potato dextrose agar) with 25°C temperature are the best combination for proper radial growth and sporulation of Corticium koleroga. In general future studies should focus on alternative intrinsic and extrinsic factors for the growth and sporulation of this pathogen.