Tree disease

Question: I have a beautiful crab apple tree in my yard. The back is falling of off the back and looks chewed.  What can I do to help this beauty? Thank you  Carol

responder: An Ask Extension Expert Replied May 22, 2023, 7:54 PM EDT
response: If you could send pictures of the entire tree, and a picture of the base of the tree (like you sent) but from a little farther away, plus closeups of any other strange thing you see on the tree, it would be helpful. I cannot tell from your picture what is going on. Thank you so much!

responder: The Question Asker Replied May 24, 2023, 10:35 AM EDT
response: Hi  Thanks for getting g back to me. Here are some new photos.we had some major damage this winter so the tree was trimmed.    Carol

responder: An Ask Extension Expert Replied May 26, 2023, 10:11 AM EDT
response: It appears that the trunk on the right has suffered a serious injury at sometime which has allowed disease to set in. If you look farther up that particular tree, in the tallest limb on it, you will see another area which is the same color and possibly another indication of disease.   You indicate that you had serious injury this past winter and had done some trimming. I'm wondering why kind of damage your tree incurred and whether it was a disease issue.   One possible issue that may be affecting your crabapple tree is a fungal disease called Botryosphaeria Canker.  A canker is basically a sore or a wound that develops from some kind of injury. Trees that are affected are typically in a weakened state to begin with. In your case, I'm wondering is simply old age could be opening the door for disease. Another issue I see with your tree is that there is no root flare visible above ground. When a tree is improperly planted (in this case, too low), some of the bark is underground. This bark then is moist much of the time, allowing for disease and insect damage to occur.  In botryosphaeria canker, new infections occur on fresh wounds, branch junctions, or through natural openings in branches and leaves. Pruning cuts, broken branches, leaf and peduncle scars, or other bark or stem injuries (such as sunburn or frost  damage), are typical entry points for the pathogen. The fungus rapidly colonizes the phloem and young sapwood and begins to  grow through inner layers of wood. This disease  will only grow on trees that are already weakened or suffering from another pathogen.  As is the case for most crabapple tree diseases, the best way to ensure your tree is safe from fungal damage is through preventative measures.  Drought can make a crabapple tree more susceptible to Botryosphaeria canker since it weakens the plant. However, overwatering, especially on the tree’s trunk, can cause the fungi to grow and spread. To prevent crabapple tree diseases like Botryosphaeria canker, ensure the growing environment is appropriate for your tree. Too little sun, too little water, or too much water in the wrong places causes Botryosphaeria canker to thrive.  Once symptoms have been spotted, prune away as much of the impacted area as possible. However, if the cankers have broken through the layers of bark into the tree’s tissue, this may not help.  To sum up, your tree could be suffering from old age, improper planting that has finally caught up with the tree, or a fungal disease. Since this tree is obviously valuable to you, your best resource for diagnosing and treating it is to consult a certified arborist. An arborist is a certified and generally insured expert in trees and their problems. He or she can examine your tree and make recommendations regarding the health of the tree, any needed judicial pruning, and whether or not (in his/her opinion) it should be removed. You can find a certified arborist in your area here:  http://www.treesaregood.org/  Click on "Find an Arborist" at the top of the page; then click on United States from the pull-down menu. Then enter your State and City. This should bring up a list of certified arborists nearest to you. Or you may be able to locate one under "Tree Services" in your local Yellow Pages.

responder: An Ask Extension Expert Replied May 26, 2023, 10:13 AM EDT
response: Here is a resource you may find helpful:  https://ag.umass.edu/landscape/fact-sheets/botryosphaeria-canker