The Rhizobium radiobacter bacterium causes irregular woody masses known as crown galls to form on the roots, trunks or branches of various species of tree including the Horse-chestnut.

It also causes galls on many dicotyledonous herbaceous species, entering the plant via a wound, often at the crown of the plant - i.e. the junction of root and stem at ground level. 

On any suitable host, including crop plants.

All year round.

Status in Britain not known.

Status in Leicestershire and Rutland not known.