Survey on occurrence of alternaria leaf blight in turmeric in Karnataka

Abstract

Turmeric (Curcuma longa L.) is known as ‘Indian saffron’ is an important commercial spice crop grown in India. The area is increasing year by year due to its culinary, medicinal and traditional usage. Although turmeric is considered to be a medicinal plant, it is susceptible to various diseases. Among the various diseases, leaf blight caused by Alternaria alternata (Fr.) Keissler, is one of the most serious foliar disease in all the turmeric growing regions of the world. In Karnataka majority of the commercially grown varieties are susceptible to A. alternata. The survey work was carried out to study the occurrence and spread of the disease in major turmeric growing areas of Karnataka. An intensive roving survey was carried out to assess the incidence of leaf blight of turmeric. The survey was conducted during 2018 and 2019 in areas Bidar, Kalaburagi, Yadgir, Raichur, Koppala, Bagalkot, Mysuru, Kodagu, Chamarajanagar, Shivamogga, Belagavi and Uttar Kannada districts of Karnataka to assess the severity of leaf blight of turmeric in the farmer’s field, when the crop is five months old the roving survey was conducted in 51 villages of 30 taluks covering 12 districts of Karnataka. Among the villages surveyed, the maximum disease intensity was observed in Ilawala village of Mysuru taluk (38.80 PDI). Maximum mean disease intensity at taluk level was recorded in Mysuru taluk (38.80 PDI), whereas minimum disease intensity was recorded in Hukeri taluk (1.50 PDI) of Belagavi district. At district level, maximum mean disease intensity was recorded in Mysuru district with 39.50 PDI while minimum intensity was observed in Yadgiri district with 3.20 PDI.