A study on fungicides potential and incidence of sheath rot of rice caused by Sarocladium oryzae (Sawada)

Abstract

Sheath rot, Sarocdadium oryzae (Sawada) Gams. and Hawksw., has recently become a serious disease of rice when climatic conditions are unfavorable during flag sheath development. In this study systemic and nonsystemic fungicides were tested against S. oryzae. Maximum inhibition of radial growth (76.53%) was recorded at 10.0ppm of tebuconazole fungicides. In non-systemic fungicides, maximum inhibition of radial growth (78.86%) was recorded at 200.0ppm. Comparative efficacy of fungicides on sheath rot was tested during Kharif 2008-2009. Foliar spray of tebuconazole was found superior overall other treatments giving reduction in disease severity (59.01-64.33%), which was followed by followed by carbendazim (48.70-55.28%), and also increased grain yield per plant (45.06-65.84%), grain yield per plot (45.57-65.85%), 1000-grains weight (10.80-52.58%) and reduction in chaffiness (48.07-53.80%). Among non-systemic fungicides chorothalonil was found best in managing sheath rot, giving reduction in disease severity (35.68-38.85%), and also increased grain yield per plant (24.78-44.74%), grain yield per plot (24.52-44.57%), 1000-grains weight (4.25-35.47%) and reduction in chaffiness (15.74-45.96%) as compared to check. Another field experiment was conducted during Kharif 2009-10 to observe sheath rot incidence on rice cultivars in Tarai region. The incidence was recorded in thirty three varieties; only varieties (Type-3 and Basmati-370) were recorded as free from disease symptoms.