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Not AvailableIn any host-pathogen interactions, the disease severity is aggravated by host susceptibility and favourable climatic conditions for disease development. Hence for a disease to break into an epidemic state the following the susceptible host, favourable climate and virulent pathogen are prerequisite. In sugarcane, only few diseases are found to occur across the country and many of them are confined to selected locations. The foliar diseases like eye spot, brown spot, rust and others have been found to occur in specific season in a year or restricted to high humidity areas. Mostly these diseases occur to moderate levels in different varieties and their economic impact to crop cultivation is limited. However at times severe occurrences of the disease occur in the disease endemic regions due to deployment of susceptible varieties. During the last few years we have witnessed severe outbreak of brown spot caused by Cercospora longipes E.J. Butler in parts of Karnataka and Maharashtra. Detailed studies were conducted to assess the disease scenario and its severity and mycological investigations on the associated pathogen. Among the different varieties under cultivation, the disease was found to occur only in the cv CoM 0265 in the region affecting the crop productivity severely. Detailed histological studies revealed that C. longipes conidiophores fascicle emerged near the stomatal pores and each conidiophore fascicle ranged from 50-200µm in diameter with a height of ~50-250µm from the surface. Each fascicle had ~15-20 olive brown conidiophores arising from the stroma base. The conidia were hyaline, straight or slightly curved, broader at the base and a long tapering point with 5-8 septations and measured 40-70 x 3-7µm size (length x width). The associated pathogen was clearly described based on mycological parameters for the first time from India. Impact of minor diseases becoming major diseases and its impact to sugarcane is discussed in detail in the paperNot Availabl