about the diseases effecting rice plant

1. MAJOR RICE DISEASES
A) SHEATH BLIGHT B) BLAST C) BACTERIAL BLIGHT
FUNGUS RHIZOCTONIA SOLANI FUNGUS MAGNAPORTHE ORYZAE XANTHOMONAS ORYZAE
TELEOMORPH:
THANATEPHORUS CUCUMERIS
Effects aerial part of plant & Small diamond shaped lesions on Water soaked lesions with
Specifically the sheath of rice. leaves, expands & coalesce to a yellow halo on leaves
Water soaked lesions, light brown form blast lesions effects leaf panicle &stem
to greyish & cause lodging.
Spread by Mycelium & By spores conidia By Bacterial ooze from
Sclerotia infected plant

2. SHEATH BLIGHT OF RICE
MAJOR CONCERN
1. The causative pathogen, R. solani, has high genetic diversity. it has been classified in to 14 anastomosis group
(AG1 –AG13, AGB1)
Based on morphology of sclerotium and host plantd AG1 is further divided in to three subgroup IA, IB, IC
AG1 IA is the Dominant anastomosis group causing ShB.
2. Dormant sclerotia can live in soil for several years & serve as primary inoculation for next cropping season
3. This can float and disperse over long distance with irrigation water and gather around rice plant.
4. The resistance gene in plant is QTl and absence of a complete resistant variety makes is more severe.