PrintSend to friend
1. The bacterium Xanthomonas oryzae pv. Oryzae is strict aerobe, gram negative, non spore forming, rod shaped with size ranging from 1-2 x 0.8-1.0um with monotrichous polar flagellum of 6-8 um. The bacterial cells are capsulated and are joined to form an aggregate mass. Colonies are circular, convex with entire margins, whitish yellow to straw yellow later and opaque.
2. 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 25-30OC and application of excessive nitrogen, especially late top dressing.
3. Mode of Spread and Survival: The infected seeds as a source of inoculum may not be important since the bacteria decrease rapidly and die in the course of seed soaking.
4. The pathogen survives in soil and in the infected stubbles and on collateral hosts like Leersia spp. Plantago najor, Paspalum dictum, and Cyanodon dactylon. The pathogen spreads through irrigation water in dry season and also through typhoons and rain storms.
C S Azad University of Agriculture and Technology, Kanpur