Biocontrol of rice sheath blight with formulated Pseudomonas

ABSTRACT: Previous reports from our laboratory have documented the efficiency of P. putida PpV14i in the control of sheath blight disease of rice, both in vitro and in vivo. The present study focuses on the development of an effective formulation of the bacterium for increased shelf-life. Of the various combinations tested, methyl cellulose:talc in the ratio 1:4 was found to maintain the bacterium in a viable state for up to 10 months, affording 60 % suppression of sheath blight in the field on par with the fungicide validamycin. Further more, the formulation had no adverse effects on seed germination. The results were consistent when tested by the detached leaf assay in vitro. Key words: Sheath blight, Pseudomonas put ida, Rhizoctonia so/ani, rice, formulation Sheath blight of rice caused by Rhizoctonia solani is the most important disease which causes significant losses in rice growing countries. Intensive cultivation of modern high yielding, early maturation, high tillering rice varieties with double cropping and high doses of nitrogenous fertilizers, leads to more disease severity, eventually yield losses of about 50 % due to sheath blight disease have been reported in Japan, Vietnam