Brown spot of sugarcane: an emerging disease in South Western region in India

Abstract

The foliar diseases like eye spot, brown spot, rust and others in sugarcane have been found to occur in specific season in a year or restricted to high humidity areas. However, deployment of susceptible varieties in a disease endemic regions aggravates its severity. 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). Impact of minor diseases becoming major diseases and its impact to sugarcane is discussed.

Keywords

• sugarcane
• brown spot
• cercospora longipes