Rice blast or rotten neck of rice

Catalogue Type
Plant Diseases Catalogue
Scientific Name
Pyricularia oryzae (Perfect stage- Magnaporthe grisea)
Distinguishing Characters
-Symptoms may occur in any parts of the plant above ground like in leaf, leaf sheath, culm, panicle, glumes.
- First symptoms appear on the leaf.
- Initially, pin head size spots occur in the leaf lamina (color of these spot is light brown).
- in the later stage, the spots become circular, oval or elongated.
- Different races of the pathogen are seen in different region for example the blast spots in surkhet are much different than that in chitwan. (in surkhet very large spots are seen)

- In culm, symptoms are different.
- Brown to black lesions are found. Sometimes those lesions completely encircle the culm. If such ring formation is in earlier stage, grains are not filled only the chaffy (Vus) grains are formed. If such ring formation is in later stage, panicle hang down and even break and fall off.
- In glumes also the black lesions are found. In those lesions sometimes ash colored fungus growth is noticed where spores are also found.
- The color of circular spots sometimes changes to bluish. That is due to conidia formation. In such spots heavy sporulation occurs.
Host Crop
Photo of Pathogen
Photo of Damaged Crop