Infection type

Symptoms

0

0(4)

No visible symptoms (immunity).

Sparse small colonies originating from the stomatal subsidiary cells.

1

Necrotic flecks, usually minute.

No mycelial growth. No sporulation. (Hypersensitivity).

2

Frequent chlorosis.

Reduced mycelial growth. No or very scare sporulation.

3

Moderate mycelial growth, moderate sporulation. Sometimes chlorosis.

4 

Profuse sporulation of well developed colonies and sometimes green islands.