Biological Control of Rice Sheath Blight with Antagonistic Bacteria

Of the five isolates, Pseudomonas fluorescence (Pfr 1 & Pfr 5), fluorescent pseudomonads isolate 19 (FLP 19), 82 (FLP 82) and 90 (FLP 90) screened against Rhizoctonia solani in vitro Pfr1 and Pfr 5 grew very fast and attained a radial growth 23.70 mm after 48 hrs. In dual culture test, 71.2% inhibition of mycelial growth of R. solani was observed with Pfr 1 followed by Pfr 5 which resulted in 66.4% inhibition. Viability of pathogen sclerotia after emergence in bacterial suppression declined with prolonged incubation periods and at the end of 5 weeks, most of the isolates caused 7–100% loss in sclerotial germination. Maximum reduction in disease severity (67.8%) along with increase in grain yield (31.6%) was recorded when R. solani was applied 7 days after application of Pfr 1 followed by Pfr 5 which resulted in 64.5 and 40.7% reduction in disease severity and incidence, respectively.