Bakanae disease / foot rot

Infected plants several inches taller than normal plants in seedbed and field
Thin plants with yellowish green leaves and pale green flag leaves
Drying of seedlings at early tillering
Reduced tillering and drying leaves at late infection
Partially filled grains, sterile or empty grains for surviving plant at maturity
In the seedbed, infected seedlings with lesions on roots will die, which may die before or after transplanting

Identification of pathogen:

The pathogen sexually produces ascospores that are formed within a sac known as ascus.
The asci are cylindrical, piston-shaped, flattened above and are 90-102 x 7-9 µm. They are 4 to 6 spored but seldom 8 spored.
Hyphae are branched and septate. This fungus produces micro and macroconidiophores bearing micro and macroconidia respectively.
The sclerotia are 80 x 100 µm. They are dark blue and spherical. The stroma is more or less plectenchymatous and yellowish, brownish or violet.

Management:

Clean seeds should be used to minimize the occurrence of the disease.
Salt water can be used to separate lightweight, infected seeds from seed lots and thereby reduce seed borne inoculum.
Seed treatment using fungicides such as thiram or thiophanate-methyl or benomyl is effective before planting or Benomyl at 1-2% of seed weight may be used as dry seed coating
Seed treatment with organomercurials such as Agrosan GN or Ceresan @ 2 g a.i./kg seed is highly effective; steeping seeds in 1% copper sulphate solution or 2% formalin also recommended.

Source-