Influence of weather factors on the incidence of Alternaria blight of cluster bean (Cyamopsis tetragonoloba (L.) Taub.) on varieties with different susceptibilities

Abstract Progression of Alternaria blight intensity was observed fortnightly during 1997 and 1998 on six varieties of cluster bean ranging in their susceptibilities to the disease. The disease progressed faster on the most susceptible variety (FS-277) during both the years. There was a significantly positive correlation between the disease severity and certain weather parameters (cumulative rainy days and cumulative rainfall) whilst maximum temperature was significantly negatively associated (pooled basis). The step-wise multiple regression analysis of data revealed that minimum temperature, relative humidity in the evening, sunshine and cumulative rainfall played a major role in disease development.