Screening the efficacy of Seaweed extracts against sheath blight of rice caused by Rhizoctonia solani (Kuhn)

摘要

Rhizoctonia solani is the causative agent of rice sheath blight, which has become a major problem in rice production. Seaweeds provide a rich source of structurally diverse and biologically active secondary metabolite and is proved to be better to decrease the foliar fungal diseases which ultimately increase its fertility and help the growth of plants. The use of natural products becomes the ultimate way of combating this disease. In this context, 15 different seaweeds were used against sheath blightdisease. Evaluation of seaweed againstR. solani was carried out by spore germination assay, paper disc assay and agar well method. Among the sixteen seaweeds extracts tested, extracts of Sargassum wightii [brown seaweed algae] at a high concentration (20%) was found to be the best the in thereduction of spore germination (18.12 per cent). The leaf extracts of Sargassum wightii [brown seaweed algae] at highest concentration of (20%) showed a maximum reduction in both paper disc method and agar well method with 46.15 and 45.12 per cent zoneof inhibition respectively.