Soft
rot/black leg
Soft
rot of potato caused by bacteria is a serious problem
of potatoes in storage as well as transit while in the field it causes black leg.
Soft rot of tubers and black leg or stem rot is mainly caused by coliform
bacteria called Erwinia carotovora ssp.
carotovora, E. carotovora ssp. atroseptica, E. chrysanthemi. The same
pathogen also causes the black leg in fields. Losses caused by bacterial decay
in seed and storage are very common. Extreme tuber losses of more than 80% have
also been recorded in poorly
ventilated transport system. Soft rot of potato can be observed at any stage
right from tuberization in field until it reaches the market and /or consumer.
The
disease is not only present in the cool, temperate climates but also in the
warm, tropical potato growing region of the world. The incidence of the disease
is greater in the tropics due to high temperature and humidity. For management of
the disease a combination of methods including avoidance,
exclusion
and eradication
are to be practiced.