Heat treatment of seed tubers for control of potato blackleg (Erwinia carotovora subsp. atroseptica) and other diseases

The thermal death points of Erwinia carotovora subsp. atroseptica and subsp. carotovora were determined in relation to duration of heat treatment, age of culture and culture medium. No isolates cultured in liquid media survived heating at 53°C for 5 min while those on solid media were killed by heating at 54°C for 10 min. After immersing naturally contaminated potato tubers for 10 min in water at 55°C, Erwinia could not be detected. The same treatment of naturally or artificially contaminated seed tubers gave complete absence of blackleg infection in the field and decreased the amounts of powdery scah(Spongospora subterranea) and black scurf (Rhizoctonia solani) on progeny tubers.