A common and widespread plant disease which can affect a very wide range of woody and herbaceous plants. The disease is caused by the bacterium Agrobacterium tumefaciens. Galls are formed at the crown (stem–root junction) or, less commonly, on roots, stems, or branches of infected plants. On herbaceous plants the galls are usually soft, while on woody plants they tend to be hard. On trees, crown galls may reach sizes of 1 metre or more across.
Subjects: Biological Sciences — Chemistry.