1A disease of pine trees which causes the trunks to decay (now rare).
2A disease of the potato caused by the bacterium Corynebacterium sepedonicum and resulting in rings of yellow rot in the tubers, a serious problem in parts of North America and northern Europe.
Origin
Late 19th century.
Definition of ring rot in US English:
ring rot
noun
1A disease of pine trees which causes the trunks to decay (now rare).
2A disease of the potato caused by the bacterium Corynebacterium sepedonicum and resulting in rings of yellow rot in the tubers, a serious problem in parts of North America and northern Europe.