Ecofriendly Management of Blast Disease of Rice Through Bio-products"

Abstract

Rice(Oriza sativa L.) is one of the important crop. This is the first largest grown crop in the world. It contributes about half of the total food grain and 55% of total cereal production. Rice blast is one of the most wide spread disease and found in all rice growing area of the world. The typical symptoms are characterized by lesions or spots appear as minute brown specks, then grow to become spindle shape pointed at both ends. The centre is greenish grey often showing a brownish margin. The pathogen was isolated from naturally infected leaf and the fungus was purified. In the pathogencity test the symptoms were found on leaf and Panicle. Management of diseases has been generally achieved by the use of synthetic pesticides, but these are known to pollute the environment, soil and water, beside deleterious effect on human health . A number of plants are known to possess antifungal activities which could be exploited for environmentally safe and ecofriendly method of disease management. The use of botanicals and organic substance may be an effective source to the management of blast disease of rice. During the present investigation to find out the efficacy of different substances against M.grisea , four plant extracts(Neem, Datura, Backain and Azwain), four organic substances(Varmicompost, Chicken manure, Neem cake and Cow urine)and one agrochemical were tested in vivo and in vitro. During the present investigation, all extracts were evaluated for the fungal toxicity against M.grisea by using poison food technique. All extracts inhibit radial growth but in case of chicken manure, cow urine and neem leaf showed maximum radial growth inhibition at all the concentration (1,5 and 10%).The percent disease control by chicken manure and cow urine was achieved 47.03% & 40.35% infield experiment. All extracts were found inhibitory to the radial growth of test pathogen in vitro . Based on present investigation, it can be concluded that the fungi toxic properties of these substances may be of great importance in plant disease management, as alone or in combination with these substances particularly as an important component in integrated disease management programme for plant pathogens.