Suffering cherry tree

Asked July 27, 2018, 8:10 PM EDT

My cherry tree's leaves are turning yellow and dropping, and has amber pitch balls dotting down one side. The tree is old was full grown when I bought the house 14 years ago, and had cherries for the first ten years then stopped bearing for a couple years before getting hit with a crazy blight that dries up the blossoms before they fall. I love the tree and have used Neem Oil for three years and finally this year tried copper on it, as pre-emergents but not having success. Can this tree be saved? Thanks for any suggestions or help you can give me. Leola

Lane County Oregon cherry trees horticulture

1 Response

Leola, thanks for your question!

Can the tree be saved? I guess that depends on how far gone it is. If you can send photo that may give me a better idea. The amber pitch balls are a sign of stress, which may be due to any number of sources. The affliction you described on the blossoms sounds like a disease known as brown rot blossom blight. Take a look at the following webpage to see if the description and images match what you've observed...

https://pnwhandbooks.org/plantdisease/host-disease/cherry-prunus-spp-brown-rot-blossom-blight-fruit-...

If so, sprays need to be made throughout the bloom period. Products listed for home use include...

Captan (wettable)
Daconil (many trade names available; active ingredient is chlorothalonil)
Copper (note: rated with low control and may encourage resistant bacteria)
Immunox (a Spectracide product; active ingredient is myclobutanil)
Infuse (a Bonide product; active ingredient is propiconazole)
Sulfur (wettable)

The two "wettable" products are difficult to apply with home use sprayers. Both Immunox and Infuse are in the same family of fungicides. To avoid resistance and also avoid messy wettable products, I recommend alternating from one application to the next between Daconil and either Immunox or Infuse (Immunox likely will be easier to find).

In addition to spray, proper pruning will be important to remove dead material. Due to disease susceptibility, we often avoid pruning cherries during the winter when it is wet. Ideally we would prune them immediately after harvest. While it is little on the late side, if there is dead/damaged/diseased/dying material present, I recommend removing it as soon as possible. It is important to avoid pruning too late in the summer, because pruning can cause new growth that will not have the chance to harden off prior to the onset of cold weather.

Is the tree getting adequate (but not too much) water? A good deep watering about once every two weeks is all it needs. It can handle more frequent watering, but daily watering of a lawn, for example, may be a bit much. Also, keeping irrigation water out of the canopy is important to avoid the spread of disease.

Please let me know if you have any additional questions.