Verification of our identification of a peach tree disease?

Asked May 12, 2020, 2:48 PM EDT

Hello! We planted a peach tree (Elberta Peach; purchased from a reputable vendor in Denver) last summer; it looked very healthy all of last season and produced beautiful fruit. After learning that we lost a young apple tree to fire blight, we checked on the peach and noticed that many of the young, pliable branches are discolored in patches of brown, some with white spots in the middle. A few pictures are attached. On these branches, many of the leaves are stunted and disfigured, although we initially attributed that to the most recent freeze that affected peaches across the state. A few branches are not producing leaves at all, are dark purplish-brown, and look withered and wrinkled like a dried apple skin. Based on an internet search, we suspect that the tree may be affected by cytospora canker, and wanted to ask if you could please 1) confirm/dis-confirm our identification, 2) provide additional insight into what disease may be affecting the peach, and 3) provide advice for treatment options if the tree is not too far gone?

Denver County Colorado

1 Response

Those darkened, discolored areas are called cankers and if they enlarge to girdle the stem, they well can kill everything above it. Based on these photos, I can't confirm that your tree has cytospora but I can tell you that cytospora affects stone fruits like peach and that stress is often a contributing factor. You can't control the weather which has been putting a lot of stress on trees for the last few years but anything else you can do to manage stress like avoiding soil compaction and providing appropriate water is helpful. We recommend you have a certified arborist diagnose your tree and recommend a management strategy. There's a good list of tree companies licensed to do business in Denver on the Denver Forestry website https://www.denvergov.org/content/denvergov/en/denver-parks-and-recreation/trees-natural-resources/forestry-trees-.html