Fungitoxic Effects of Extracts of Azadirachta Indica against Cochliobolus Miyabeanus causing Brown Spot Disease of Rice

The oil extract from seeds of Azadirachta indica as well as water and ethanol leaf extracts of the plant were effective in reducing the radial growth of Cochliobolus miyabeanus in culture and in checking the spread of brown spot disease in rice. The oil extract was found to be the most effective, followed by ethanol leaf extract, in inhibiting the growth of the pathogen in vitro and in checking the development of the disease in vivo . Although the cold water extract from the plant leaf reduced the radial growth of the pathogen in culture, it failed to reduce the incidence and severity of the disease as effectively as the oil and ethanol extracts. The oil and ethanol extracts compared favourably with carbendazim (Bavistin) at 0.1% a.i and have the potential for control of brown spot disease of rice in the field.