Dying branches on Cherry Tree - Ask Extension
Last year, my cherry tree experienced a mysterious leaf, die off on one branch, as did my neighbors cherry tree. I had not yet removed the branch this...
Knowledgebase
Dying branches on Cherry Tree #872514
Asked June 10, 2024, 7:43 PM EDT
Last year, my cherry tree experienced a mysterious leaf, die off on one branch, as did my neighbors cherry tree. I had not yet removed the branch this spring and now a second branch is also dying. What is going on with the tree and how can I treat it?
Baltimore County Maryland
Expert Response
Ornamental (flowering) cherry trees are susceptible to several pest and disease issues, particularly following a period of stress (like from drought) or injury (like from storm damage or trunk wounds). One pathogen common to cherries, both edible and ornamental, is Brown Rot, which can cause branch dieback, though generally only nearest the twig tips. As with other infections, if the diseased or dead wood is not promptly removed, it can support the production of more infectious spores that may spread the disease to more parts of the tree as spores splash around in rain or blow around in windy weather.
Overlapping conditions could include wood-boring insects further down the length of the branch, which cut off the sap flow to the foliage (causing their wilting, drying, and death), or a canker infection, which has the same impact. Of the latter, Cytospora fungal canker is among the most common and aggressive in causing branch death. Both borers and canker-causing infections tend to take advantage of trees under stress, even if symptoms of that stress are not prominent, while Brown Rot tends to act independently and is more weather-dependent with regards to severity and spread. In the case of your photos, we think more than just Brown Rot is present, given how much dieback is present.
We suggest that the dead and dying wood be pruned off now, to avoid spreading any infectious spores further. Hire a certified arborist if you don't feel comfortable pruning yourself, as the cuts should be made in a certain location at the branch base to avoid potentially opening-up the trunk to wood decay invasion.
An arborist can also inspect the tree for other problems, like girdling roots, mower injury to the trunk, over-mulching, and borers. If wood-boring insects are present, there is nothing that can treat them once they are already inside the wood causing damage. (Preventative sprays to the trunk only keep new generations from entering the tree.) Similarly, no fungicide can cure existing disease or reverse its damage, but even when used as a preventative every spring, it could risk harming pollinators, so we generally discourage their use.
For now, after pruning, just monitor the tree for watering needs as we enter drier summer periods, and make sure the base of the trunk is not covered in mulch.
Miri
Overlapping conditions could include wood-boring insects further down the length of the branch, which cut off the sap flow to the foliage (causing their wilting, drying, and death), or a canker infection, which has the same impact. Of the latter, Cytospora fungal canker is among the most common and aggressive in causing branch death. Both borers and canker-causing infections tend to take advantage of trees under stress, even if symptoms of that stress are not prominent, while Brown Rot tends to act independently and is more weather-dependent with regards to severity and spread. In the case of your photos, we think more than just Brown Rot is present, given how much dieback is present.
We suggest that the dead and dying wood be pruned off now, to avoid spreading any infectious spores further. Hire a certified arborist if you don't feel comfortable pruning yourself, as the cuts should be made in a certain location at the branch base to avoid potentially opening-up the trunk to wood decay invasion.
An arborist can also inspect the tree for other problems, like girdling roots, mower injury to the trunk, over-mulching, and borers. If wood-boring insects are present, there is nothing that can treat them once they are already inside the wood causing damage. (Preventative sprays to the trunk only keep new generations from entering the tree.) Similarly, no fungicide can cure existing disease or reverse its damage, but even when used as a preventative every spring, it could risk harming pollinators, so we generally discourage their use.
For now, after pruning, just monitor the tree for watering needs as we enter drier summer periods, and make sure the base of the trunk is not covered in mulch.
Miri
