Field Identification
The world’s heavyweight rice pathogen—diamond-shaped necrotic lesions with gray centers on leaves, collar rot that kills tillers, and panicle blast that turns grain heads white overnight. Spores ride dew and wind through humid canopies.
Lesions enlarge under 25–28 °C nights with long leaf wetness; neck blast girdles panicles below the head. The fungus overwinters on stubble and weed grasses, so rice monoculture keeps the party funded.
How to Deal With It
Organic Control Methods
Copper and sulfur have partial activity; Bacillus-based biofungicides and silicate nutrition can strengthen cell walls—integrate with resistance and spacing; no organic rescue for panicle blast once necks girdle.
Antagonistic bacteria (Pseudomonas, Bacillus) applied as seed treatments or foliar teas show variable blast suppression in trials.
Plant resistant varieties; optimize nitrogen—lush rice invites blast; widen spacing in home gardens; destroy infected stubble; avoid overlapping crops.
Upland or SRI-style intermittent irrigation reduces leaf wetness duration compared to constant deep flood—where water control exists.
Use clean seed; scout at tillering and boot; avoid excessive shade from weeds that extend morning dew.
Let Nature Handle It
Natural Enemies
- Antagonistic Bacteria
- Competitive Fungi in Residue
- Soil Antagonistic Microbes
Threat Map