Blackleg is a plant disease of potato caused by pectolytic bacteria that can result in stunting, wilting, chlorosis of leaves, necrosis of several tissues, a decline in yield, and at times the death of the potato plant.
2. • Introduction
Potato blackleg is a bacterial disease caused by the
bacterium Pectobacterium atrosepticum. It is early
potato disease and symptoms can be seen in early
June
Infected Plant
4. Pathogen Biology:
A Gram-ve , rod-shaped bacterium.
Carried by contaminated seed tubers.
Cause disease when environmental
conditions are favorable.
6. Symptoms
Stems :
•Stem of potato plants appear pale green or yellow.
•At ground level, these affected stems appear black and
rotted.
Leaves:
•Leaves at the top of affected stems may be small and
have margins curled inward.
Tubers:
•In tuber , the flesh may be grey or brown and rotten.
10. Disease Cycle and Epidemiology
• High soil temperatures and physical attack on seed
tubers, favor seed-piece decay.
• RH - 94 to 100% & temp - 21 to 29oC
• The blackleg bacterium survives poorly in soil.
• The seed tuber is the most important source of
inoculum in the blackleg disease cycle.
• The blackleg bacterium does not survive very well
outside of association with host plant tissue.
12. Management
•Plant only certified, disease-free seed tubers
•Seed treatment
•Streptomycin sulphate 0.1 % for 10 min
•Streptocycline ( 100 ppm) and copper sulphate (
40 ppm) for 30 min.
•Removal and destruction of infected plants as
soon as symptoms are noticed.
•Rotation also reduces the risk of infection arising
from infected potatoes