19 Aug 5 Major diseases of Rice (Oryza sativa)
चावल के 5 प्रमुख रोग (ओरीज़ा सतवा) 1. Rice Blast Causal Organism -Pyricularia oryzae (Syn: P. grisea) (Sexual stage: Magnaporthe grisea) Symptom- On the leaves, the lesions start as small water soaked bluish green specks, soon enlarge and form characteristic boat shaped spots with grey centre and dark brown margin. The spots join together as the disease progresses and large areas of the leaves dry up and wither. Similar spots are also formed on the sheath. Severely infected nursery and field show a burnt appearance. At the flower emergence, the fungus attacks the peduncle which is engirdled, and the lesion turns to brownish-black. This stage of infection is commonly referred to as rotten neck / neck rot...