Management of Brown Spot Disease of Rice

An experiment was conducted to evaluate the efficacy of different chemical, botanical and biological treatments against the brown spot disease (Bipolaris oryzae)of rice in Chitwan, Nepal. Treatments were evaluated by poisoned food technique in-vitro, seed treatment in laboratory and foliar spray in the field. Saaf and Hinosan were the most effective followed by Cattle urine and Nico-neem in inhibition of mycelial growth. However seed treatment with Hinosan reduced 90% seed borne inoculum followed by Saaf. Botanicals also significantly controlled seed borne inoculum by more than 50%. In field trial, AUDPC was significantly reduced by Hinosan followed by Saaf and Nico-neem. All the yield and yield attributing characters were negatively correlated but highly significant with AUDPC. The reduction in seed borne infection by the residual effect of foliar spray was significant. The results revealed that seed treatment and foliar spray with Hinosan or Saaf may be the option for management of brown spot. Neem oil based products Nico-neem and locally available botanicals like Simali are promising for eco-friendly management of brown spot disease of rice.