Bacterial Blight of Paddy PDF

## Bacterial Blight of Paddy (Rice) **Causal organism**: *Xanthomonas orzyae* (bacteria) **Host**: Rice (*Oryza sativa*) ### Symptoms Early symptoms of the disease appear on lower leaves in the form of water-soaked translucent spots. Later on, these spots increase in size and form yellow to white...

## Bacterial Blight of Paddy (Rice) **Causal organism**: *Xanthomonas orzyae* (bacteria) **Host**: Rice (*Oryza sativa*) ### Symptoms Early symptoms of the disease appear on lower leaves in the form of water-soaked translucent spots. Later on, these spots increase in size and form yellow to white elongated streaks. The disease is characterized by the drying of the leaf tips and inward rolling and twisting of leaf blades. The bacteria oozes out with guttation drops from young lesions under humid conditions. The bacteria translocates through xylem and blocks the vascular tissues resulting in the blight so that the field gives a burnt up appearance. Grains of diseased plant also turn blackened. ### The pathogen The bacterium is small rod-shaped with single polar flagellum. It is Gram-negative and non-spore producing. ### Mode of infection The disease is seed borne. The bacteria also survives on crop-stubbles and plant body of *Cynodon dactylon*, which grows nearby the rice fields. The diseased plant oozes out secondary inoculum through lesions. It spreads and infects healthy plants through rain splashes and insects. The pathogen enters the healthy plants through stomata and wounds. ### Control 1. Use of disease-free seeds and resistant varieties (viz., W 529 and W 348). 2. Crop rotation. 3. Use of chlorinated water for irrigation. 4. Spray of fungicides and antibiotics.