Local name: naggapula (Ilonggo)
Causal organism: Xanthomonas oryzae p.v. oryzicola (Fang et al.) Swings et al.
Where to find: On leaves
Symptoms: fine translucent streaks that enlarge lengthwise; coalesce (merging lesions ) form large brown affected leaves; later stage, entire leaf turns brown and withers
Susceptible stage: tillering to maturity
Note: wind-borne, present in lowland and upland fields
Disease development and severity is favored by:
- Excessive nitrogen fertilization;
- Injured leaves; and
- High humidity, rain.
Disease Cycle
Little is known except:
- Bacteria enter leaves through stomata and wounds
- Bacterial cells are discharged on leaf surface at night
- Disease is spread by irrigation water and seeds
Disease Management
- Plant certified seeds
- Avoid high dose of nitrogen
- Destroy infected crop residue