Treatment. and you A canker is a sore that appears on your tree after it has been infected by tree diseases. Cankers can develop on the large branches or even the trunk and enlarge to the point where they’ll choke off and kill the part of the tree above them. On the limbs or trunks of the tree, the cankers are usually darker than the normal bark and will look sunken in the center. You should diagnose and treat ASAP! The most common kinds of cankers include beech bark disease, Phomopsis juniper canker disease, chestnut blight, and walnut canker disease. Cankers will often develop on the base of the buds. Stem canker problems can develop as a result of stem injury such as sunscald, winter injury or wounding. Finally, the loves of your tree will develop small brown dots. Hypoxylon Canker Diagnoses and Treatment . These will look round and will fall out, leaving holes in the tree. Bacterial canker infections occur during fall, winter and early spring (during cool, wet weather) and are spread by rain or water, and pruning tools. Both fungi and bacteria can cause cankers, with each type of organism producing different specific symptoms. Prevention is just as important as treatment when one of your plum trees has canker. Prune flowering trees during blooming when wounds heal fastest. If you have noticed your post oak trees turning brown they could have Hypoxylon Canker. The bacteria overwinter in active cankers, in infected buds and on the surface of infected and healthy trees and weeds. A: This appears to be a stem canker disease. Canker, techniques and organic treatments to avoid it Infecting most ornamental plants such as cypress , willow or fruit trees such as peach trees , apricot trees or cherry trees , canker is a fungal disease that attacks the branches and even trunk of the tree. on oak trees in Fort Worth TX property Fee evaluation just Call (817) 502-9402.