Crown Gall or Abnormal Growth on a Tree Trunk caused by Agrobacterium tumefaciens - Photos

Crown Gall or abnormal growth on a Birch tree trunk surrounded by Chestnut trees in the Fall colors in Cannobio on the shore of Lake Maggiore, Lepontine Alps, Piedmont Region, Province of Verbano Cusio Ossola. Crown Galls can cause deformities or rot in the trees and are generally caused by a bacteria (Agrobacterium tumefaciens).