Blackleg
Erwinia carotovora subspp. atroseptica
Erwinia carotovora subspp. atroseptica
Bacterium
Potatoes
Stems fail to emerge or are stunted with yellow curled up leaves. These stems can be easily pulled out and are blackened at ground level. A late attack may cause the collapse and blackening of the entire haulm.
The disease is primarily carried on seed tubers. Bacteria released from the rotting seed tuber attack developing shoots and prevent emergence. Later attacks cause a wet rot on emerged stems (blackleg). The disease also develops in daughter tubers as soft rot.
Favourable Factors
Wet conditions.
A few infected plants may be found in most crops, but losses in the growing crop are usually small.
Find out more information on the key disease threats to your potato crop. For each disease you will find out the importance of the disease in terms of potential yield penalty, how to identify the disease in its early stages and our advice on the best control strategies.