Bacterial leaf blight is a disease of rice caused by the bacterium Xanthomonas oryzae pv. oryzae. It was first identified in Japan in 1884. The disease causes wilting and death of rice seedlings within 3-4 weeks of transplanting. It enters through natural openings or wounds in the leaf. Lesions form on the leaves and turn yellow. Dew drops containing bacterial masses form on young lesions. The bacterium can be transmitted by irrigation water, rain, plant contact, or contaminated tools. Warm temperatures between 25-30 degrees Celsius and heavy rain or flooding create favorable conditions for the disease. Management strategies include growing resistant varieties, destroying infected plant debris, avoiding wounding of seedlings

1. BACTERIAL LEAF BLIGHT

2. BACTERIAL LEAF BLIGHT
• CASUAL ORGANISM : Xanthomonas oryzae pv. oryzae
• Telugu name : bacteria aaku endu tegulu
• First identified in japan 1884 [Indonesia]

3. SYMPTOMS AND SIGNS
• Wilting of plants . Wilt syndrome known as Kresek is seen in
seedlings within 3-4 weeks after transplanting of the crop.
• The bacterium enters through the hydathodes and cut
wounds in leaf tips, and cause death of entire seedling.
• The lesions enlarge both in width and length with a wavy
margin and turn straw yellow within few days.
• Milky dew drops containing bacterial masses are formed on
young lesions in the morning.

4. DISEASE CYCLE
• INOCULUM : Inoculum present in rice stubble and weed hosts.
• The pathogen may be present for a short time on infected
seed and soil.
• TRANSMISSION : The bacterium spreads by irrigation water,
rain, plant to plant contact, and tools for transplanting
seedlings.
• INFECTION : The bacterium enters leaf tissues through natural
openings such as hydathodes and stomata on leaf blades ,
wounds on leaves and roots. Some bacteria invade the
vascular system and may ooze from hydathodes.
• PRIMARY INFECTION : through seeds.

5. FAVOURABLE CONDITIONS
• Clipping of tip of the seedling at the time of transplanting.
• Heavy rain.
• Heavy dew.
• Flooding.
• Deep irrigation water.
• Severe wind.
• Temperature of 25-30 degrees.
• Application of nitrogen.

6. MANAGEMENT
• Grow resistant cultivars like MTU 9992,Swarna,Ajaya,etc.
• Affected stubbles are to be destroyed by burning or through
ploughing.
• Judicious use of nitrogenous fertilizer.
• Avoid clipping of tip of the seedlings at the time of transplanting.
• Avoid flow of irrigation water from infected to healthy field.
• Spray psuedomonas florescens at 1kg per acre with 200lt of water.
• Application of bleaching powder@ 2kg/acre in the irrigation water
at kresek stage {>60 DAT}.
• Soak seeds with Agromycin followed by hot water treatment and
spray streptomycin 250ppm