Abstract

EVALUATION OF SELECTED PLANT EXTRACTS AGAINST XANTHOMONAS ORYZAE PV. ORYZAE CAUSING BACTERIAL BLIGHT OF RICE

A Yugander, D Ladhalakshmi, M Srinivas Prasad and G S Laha*

Abstract

Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae (Xoo), remains a major production constraint in rice cultivation. The extent of yield loss could be as high as 50% and depends on the growth stages of the crop, cultivar, season, climatic condition and level of nitrogen fertilizer applied. Chemical control of the disease is not very successful. Use of botanicals in the management of plant diseases is gaining importance as it is safe and eco-friendly. In the present study, the efficacy of 33 plants extracts from different family was tested for their antibacterial activity against Xoo. Antimicrobial activity of aqueous plant extract was determined by agar well method on MWA agar medium. Among these extracts, six plant extracts exhibited significant antibacterial activity against Xoo. Out of these five plant extracts were evaluated under field condition for their effectiveness to reduce the BB. Out of these, three plants extract viz., Curcuma domestica, Datura metel and Oscimum sanctum were most effective which is reflected in reduced lesion length. All the treatments significantly increased the yield.

Keywords: Bacterial blight of rice, Xanthomonas oryzae pv. oryzae, Pathogenicity.