Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow . Galls are abnormal plant tissue growths and can be caused by a variety of organisms, and most of the galls we notice are only cosmetically damaging. But Bacterial crown gall affects a wide variety of orchard fruits and is caused by the pathogen Agrobacterium tumefaciens – tumefaciens meaning causing tumors. This fungus is capable of causing harmful growths on more plant species than any other pathogen. Only monocots