LAUSR

Abstract Rice sheath blight causes serious damage to rice crops in China. The most common practice for rice sheath blight control is still chemical treatment, an environmentally unfriendly way. Studies have demonstrated the use of nitrogen-fixing cyanobacteria to prevent crop diseases as well as to improve soil fertility and crop productivity. However, little information is available on the biocontrol of rice sheath blight using cyanobacteria. Therefore, the objective of the present study was to screen and evaluate the biocontrol effect of nitrogen-fixing cyanobacteria against the disease through microchamber and microarea experiments. Based on the results of the microchamber experiment, three strains (SCAU04, SCAU15, and SCAU26) out of nine nitrogen-fixing cyanobacterial strains with a significant inhibition (>80%) on rice sheath blight were selected. Further, microarea experiments during two seasons demonstrated the highest disease control efficacy (54.5%) on day 20 with SCAU26 treatment. Moreover, the algal treatments significantly promoted root length, underground biomass, and number of grains per panicle. SCAU04 and SCAU26 treatments significantly improved the rice theoretical yield and significantly (P