Bacterial leaf blight is one of the most serious diseases and poses challenge in rice production. Yield loss due to bacterial blight in rice has been estimated from 6% to 70%. During south west monsoon season the disease is dominating in rice.

The rice leaf blight is caused by Xanthomonas oryzae pv oryzae (Xoo).  Leaf blight symptoms are characterized by yellowing and drying which begins at the tips of the rice leaves and spread down one or both sides of the leaf or the mid vein. The bacteria entre inside the leaves through cut end of leaf tissue or natural opening hydathodes. The bacteria multiply inside the phloem vessels and produce extra cellular polysacharide called Xanthenes in huge quantity. This makes blocking of xylem vessels and prevents the water movement leads to drying of leaves and prevention of photosynthesis. The bacteria come out from the leaf in the form of yellowish drops called bacterial ooze that accumulates on the leaf surface (Figure 2). Spreading of pathogen takes place through wind and rain by splashing the ooze.