Why my apricot tree is dying after blooming and starting fruits?
Thank you for contacting the Toronto Master Gardeners with your question.
Like other stone fruits, Apricot (Prunus) trees are subject to several bacterial or fungal diseases which could cause the general symptoms you have described. I will provide you with the most likely suspect , along with their details to help you to make the proper identification, and help you with the best course of action. However in either case if this is most of the tree crown exhibiting these symptoms, it is unlikely you will be able to save your tree, and proper removal and disposal should be sought after. If there are only a few branches, or a section of your tree exhibiting these symptoms, then please do refer to the recommended treatments where applicable.
In order of their likelihood, here are several suspect diseases;
- Bacterial Canker
Description: Bacterial canker is caused by the bacteria Pseudomonas syringae. that causes the bark on affected limbs turns brown and those limbs or trees may refuse to bloom or leaf out in the spring. Sometimes though , the trees will leaf out, but these new leaves quickly wilt and die (similar to what you seem to be describing). So if you can inspect the bark and find some browning blotches that may even ooze, then this is your most likely candidate. Severe winters seems to enhance this disease.
Mechanical removal is recommended for any affected branches. Cut at least 6 inches below where you see any brown spots or lesions on branches, and keep going until you find healthy wood in case the infection is spreading inward. Disposing of infected tissues immediately can also help stop the spread of this disease.
Please refer to following link for more details on bacterial Canker;
https://extension.psu.edu/bacterial-canker-of-stone-fruit-in-the-home-fruit-planting
2. Phytophthora Root and Crown Rot
Description: Leaves of infected trees wilt, dry, and remain attached to the tree. Chronic infections, usually of the roots, cause reduction in growth and early senescence and leaf fall. In an effort to distinguish a diagnosis, a key difference would be the absence of stem cankers and ozzing sap, in which case this fungal disease is more likely he cuprit.
Heavy or poorly drained soils , or extended soaking periods can be contributors to this fungal disease. Fungicides are effective in controlling this disease when used preventively, but they are seldom effective in reviving trees once the crown has become infected and moderate symptoms of decline have appeared.
Please refer to following link for more details on bacterial Phytophthora Root and Crown Rot;
https://ipm.ucanr.edu/PMG/r5100611.html
3. Verticulum Wilt
Foliar symptoms typically include wilting, curling, yellowing, marginal or interveinal browning and death. Symptoms may include dieback of branches or a portion of the plant. Also, wood under the bark may exhibit discolored streaks or bands.
There is no cure for this disease.
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General sanitation for removal:
When removing infected tree or branches, be careful not to expose other neighboring fruit trees in the removal process. Ensure that you are very thorough in sanitizing your pruning equipment (with rubbing alcohol or bleach), so as not to spread disease. It is also advisable to refrain from re-planting another fruit tree in this spot as a replacement, because these pathogens persist in the soil for several years, and will infect a new fruit tree.
Best of luck .