Causal Agent:
Pectobacterium atrosepticum, Dickeya spp.
Biology:
Blackleg begins with planting infected seed. Seed can be infected during seed production, handling, cutting, and planting. Infected seed pieces sometimes rot before emergence — this is called seed piece decay. Not all infected plants produce symptoms, but can still pass the infection to progeny tubers and therefore into storage.
Dispersal:
Blackleg occurs everywhere potatoes are grown.
Management:
Further Reading:
Pacific Northwest Pest Management Handbooks