Standardization of isolation techniques for Pseudocercospora griseola

Angular leaf spot of common bean, caused by the hemibiotrophic fungus Pseudocercospora griseola, is one of the most widely distributed and damaging diseases of common bean, resulting in yield losses up to 80 per cent. Successful culturing of P. griseola is pre-requisite to conduct the experiments for development of management strategies against the disease, but isolation of P. griseola is difficult as pathogen is slow growing and generally dominated by saprophytes. To address this issue, different isolation techniques were evaluated for the successful isolation of P. griseola from infected leaf samples. Four different methods viz., the use of infected leaf bits sterilized toothpicks, moist chamber technique and picking up synnemata from diseased samples were evaluated and among them, picking up synnemata from infected leaves was found most efficient with 58.0 per cent recovery efficiency followed by moist chamber technique with 40 per cent recovery efficiency.