Ozone for Plant Pathological Applications

Abstract The effect of ozone on Xanthomonas oryzae pv. oryzae, a bacterium causing leaf blight disease in Paddy (Oryza sativa), was studied in culture. Viability of this pathogen was lost by flushing ozone at a flow rate of 300 ml/min for 3 minutes in culture condition. The inhibitory effect was dependant on cell concentration and time. With a cell concentration of 0.008 OD at 540 nm, the inhibition of the bacterium was total and no growth was observed in nutrient agar plates even after 36 hrs. With higher concentrations of cells (0.08 OD and above) the bacterium survived, though there was a bacteriostatic effect initially. Conductivity of the cell suspension increased after ozone treatment owing to altered cell membrane permeability and subsequent release of cellular contents. As the bacterium is seed borne, washing the paddy seeds with ozonized water would help control the bacterial blight of rice, the most serious disease of rice in Asia. Keywords: OzoneAgricultural ApplicationsPlant Pathogenic bacterium Xanthomonas oryzae pv. oryzae Oryza sativa InhibitionLeaf Blight