Brown rot disease of Potato is also called as Bangle blight
which is the causal organism of brown rot of Potato?
Bacteria called Ralstonia solanacearum
what are the Symptoms of brown rot disease of potato?
At the time tuber formation wilt is the main characteristic symptom.
In leaf symptom – wilt, stunt and yellowing. Browning of xylem tissue. Eye buds are black in colour.
Bacteria ooze coming on infected tuber surface and emits a foul odour.
what are the characteristic features of pathogen causing Brown rot of potato?
G –ve, short rod, 1-4 flagella.
Colonies are white to brown in colour
what are the Favorable conditions for the development of Brown rot of Potato?
Temp 25to 35ºC , RH above 50 % and PH 6.2-6.6 favours for the development of disease.
Acid soil is not favourable.
what is the Mode of spread and survival of bacteria causing brown rot?
Infected soil and seed tubers form the main source of the primary infection.
Brown rot affected plant parts decay and release masses of bacteria in the soil where these may remain viable from season to season.
The bacteria in the soil are disseminated by wind from one field to the other.
The infection usually occurs through wounds in the root system.
how is the Disease cycle of bactria causing Brown rot?
R. solanacearum is a soilborne and waterborne pathogen; the bacterium can survive and
disperse for various periods of time in infested soil or water, which can form a reservoir source
In potato, the brown rot pathogen is also commonly tuber borne.
The bacterium usually infects potato plants through the roots (through wounds or at the points of emergence of lateral roots).
Under favorable conditions, potato plants infected with R. solanacearum may not show
any disease symptoms.
In this case, latently infected tubers used for potato seed production may play a major role in spread of the bacterium from infected potato seed production sites to healthy potato-growing sites.
R. solanacearum can survive for days to years in infected plant material in soils, infested surface irrigation water, infected weeds, and infected potato washings and sewage.
From these sources of inoculum, bacteria can spread from infested to healthy fields by soil
transfer on machinery, and surface runoff water after irrigation or rainfall. Infected semi-aquatic
Weeds may also play a major role in disseminating the pathogen by releasing bacteria from roots into irrigation water supplies.
Further readings and referemces