SOFT ROT AND BLACK LEG OF POTATO

PATHOGEN:
Soft rot: Erwinia carotovora pv  carotovora.
Black leg: Erwinia carotovora pv  atroseptica.

SYMPTOMS OF SOFT ROT:

1. The soft rot symptoms begin as small water soaked lesion, which enlarges rapidly in diameter and in depth.
2. The affected area becomes soft, mushy and depressed. Tissue within the affected region becomes cream coloured and slimy, disintegrating intu a mushy mass of disorganized cell.
3. The outer surface remain intact while the entire contents have changed to a turbid liquid. Cracks develop and slimy mass exudes to the surface which turns tan, grey, or dark brown in air.
4. A whole fruit or tuber may be converted to a soft watery, decayed mass within 3-5 days. Infected fruits or tubers of many plants are collapsed and then secondary bacteria grow on decomposing tissues and produce a foul odor.