Organic amendments and rice sheath blight management

Abstract

Soil amended with rice straw compost significantly reduced rice sheath blight severity. The disease caused by the fungus Rhizoctonia solani Kühn is a severe disturbance to rice cultivation in Indonesia. R. solani is soil borne fungi and highly competitive as saprophyte. In mature compost, R. solani propagules in the form of sclerotia germination were suppressed by hyperparasites and other biological control agents. Compost maturity level affects the ability of sclerotia to germinate. Initial inoculum reduction as sclerotia in steril soil was studied in glass house which is treated with the addition of variations in the maturity of the compost. Result showed that mature compost added to sterile soil in the pot decreased sclerotia germination for about 14%, otherwise fresh organic matter added to steril soil increased sclerotia germination, this condition lead R. solani grew and new sclerotia formed in the soil surface. The decomposition levels of organic matter influences disease development, it significantly affected on disease severity. Disease severity of rice sheath blight decreased by about 32.6-39.9 % with mature compost application.