Blast (Pyricularia grisea)

Major symptoms of the disease are leaf blast and neck blast. Sometimes nodal infection is also seen.

Symptoms on leaves appear as spindle shaped water soaked greyish green spots, which gradually enlarge in size and develop to spots with grey centre and brown margin. Such spots coalesce together resulting in drying up of the leaves and collapse of the entire plant. The fungus infect the neck of the panicle causing dark brown to black lesions resulting in rotten neck or neck blast. This will also lead to breaking of the panicle at the neck region. The grains will be partially filled or unfilled If the panicle is infected before grain filling stage, the entre panicle will be chaffy.

Sheath blight (Rhizoctonia solani)

Symptoms first appear on the lower leaf sheath near the water level as oval, oblong or irregular greenish grey spots, which enlarge and become greyish white with brown margin. Under favouarble conditions, the disease spread to the leaves also. Irregular greenish grey lesions with dark brown margins develop on leaves. Under humid conditions, white mycelial growth of the fungus as well as initially white and later brown sclerotia of the fungus loosely attached to the affected portion are also seen.

Brown spot (Helminthosporium oryzae)

On the leaves small definite spots of oval or oblong shape and dark brown colour are formed. On susceptible varieties, spots are larger in size and are having light brown or grey center with dark reddish brown margin. The symptoms also appear on glumes as black oval or oblong spots or whole surface of the grain turn black and velvety.

Narrow brown spot (Cercospora oryzae)

Numerous narrow linear short brown spots are formed on the leaves.

Stack burn (Alternaria padwickii)

Symptoms appear on leaves as large oval or circular dark brown lesions with narrow distinct margins. On the affected grains pale brown to whitish spots with dark brown margin bearing black dosts in the center are formed.

Leaf scald (Rhynchosporium oryzae)

Lesions with typical zonations with dark coloured wavy lines usually start from the tip of the leaves and extend downwards or arise from the margin and advance inside.

Sheath rot (Sarocladium oryzae)

The fungus infects the leaf sheath enclosing the panicle causing oblong or irregular brown spots which later develop into a lesion with dark brown margin and grey center. The young panicle remains inside the sheath or rather chocked and emerge only partially. The grains become chaffy A white powdery growth of the fungus can be seen on the surface of rotten sheath particularly inside the sheath.

False smut (Ustilaginoidea vireus)

The symptoms visible only after flowering when infected grains get transformed to yellow to orange spore balls, which later turns to dark green or black.

Udbatta (Ephelis oryzae)

Whole panicle transformed into a cylindrical rod covered with white mycelia Later they become hard bearing many black dots.

Foot rot (Fusarium moniliformae)

Drying of leaves and leaf sheath discolouration of lower nodes and adventitous root formation are the major symptoms. Plants turn pale yellowish green, thin and some times show abnormal elongation or rot in patches in the field.