Wiktionary
crown gall
n. A disease of plants caused by infection of soil bacteria of the genus ''Agrobacterium ''
WordNet
crown gall
n. a bacterial disease of plants (especially pome and stone fruits and grapes and roses) which forms excrescences on the stem near the ground
Usage examples of "crown gall".
The insidious parasite Agrobacter causes a tumorous swelling--a crown gall.