A field survey was conducted to assess the extent of sheath rot occurrence of rice in selected rice growing areas from different districts of Tamil Nadu during the year of 2014-2015. Among the different locations surveyed for rice sheath rot incidence, highest disease incidence were found in Orathur (30.5%) village followed by Mutharasanallur (27.4%), Thennamanadu (24.5%) and the least incidence was found in Vennankuzhi (12.1%). All the isolates were inoculated into tillers of rice plants (IR36) to assess the pathogenecity. Among the different isolates of S. oryzae disease incidence were produced which were varied between 36.33 and 72.36%. Efficacy of seven different chemical fungicides such as Antracol, Avtar, ICF-310, Indofil M-45, Indofil Z-78, Merger and Saaf were screened against S. oryzae pathogen by using poisoned food technique under in vitro condition. All

the fungicides were tested at different concentration such as 100, 200 and 300 ppm level. Result of the present study revealed that, fungicides antracol, avtar, ICF-310 and merger were completely inhibited the mycelial growth of the test pathogen even at 300 ppm concentration whereas rest of the fungicides were not resulted in complete mycelial growth at 300 ppm concentration.