Survey and Surveillance on Major Rice Diseases Severity in Karnataka, India

Rice blast, sheath blight and Grain discoloration diseases of rice were becoming a serious threat to rice crop in Karnataka. The patterns of spatio-temporal distribution of disease incidence were examined in two seasons (Kharif 2012 and 2013) with main objective of statues of rice diseases in paddy growing areas of Karnataka and variability with climatic condition. Most of the fields in the paddy growing areas of Karnataka were diseased, but significant differences in disease incidence occurred among the some sites in paddy growing areas of Karnataka. The leaf blast severity showed that the highest mean per cent disease incidence 37.20 was observed in Mandya district.and sheath blight severity showed that the highest mean per cent disease incidence 41.76 was observed in Yadgir district. The spatio-temporal distribution of grain discoloration incidence in Kharif 2012 and 2013 varied with districts, the maximum disease was in Bellary (33.82% and 31.24%) followed by Koppal (31.78% and 27.16%), for sheath blight, maximum disease was in Yadgir (36.23% and 41.76%) followed by Raichur (27.16% and 30.59%) and maximum leaf blast disease was in Mandya (37.20% and 36.91%) followed by Ramanagar (36.67% and 36.54%) respectively. Many fungi have been isolated from discolored grain, Curvularia lunata (Wakker) Boed. were found as a dominant pathogen. Survey and surveillance were serve as a precursor for evolving management strategies against the disease effective for the zone in an integrated way for sustainable development of crop in the state.