Why does my cherry tree partially wither every spring?

I am seeing the same strange behavior every year with a cherry tree that is ~8 years old. Here’s what happens:

  1. In early spring the branches are all alive and full of buds which all progress to healthy blossoms.
  2. A few weeks after blossoming, the petals fall off normally and leaves begin to emerge.
  3. Most branches never develop full leaves along their length, just at the tips of the branch. Most of the blossoms (~90%) do not produce any fruit at all. The remaining fruit is mostly weak with a few healthy cherries. Some branches completely wither and die.

Here are some pictures to illustrate what is happening:
https://goo.gl/photos/TbWSSe4saoi2ysYt6

The tree limps along and seems to do OK over the summer, except for some slug-like grubs that attack. Last year I manually cleaned them off and the tree seemed to do a lot better with more healthy leaves and branches, but after blossoming, the same problem.

As you can see from the pictures, the back yard is somewhat shaded, but the tree gets 3-4 hours of direct sun each day (when it isn’t cloudy - I’m in the pacific northwest). Would this cause my tree to be unhealthy?

Any ideas what is going on?

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Look for canker wounds, they will have sap coming out of them. It also could be the roots are unhappy, e.g. too much water. Also 3-4 hours of sun per day in the PNW is not really enough at all.

Let me call up a couple people from The PNW who will know more about your conditions- hey @Bradybb and @murky !

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Monilinia laxa might be the answer. Its a fungal infection entering the tree through the flowers.

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That’s just about what my Carmine Jewel sour Cherry looks like right now.It was probably caused by the very wet Spring.
John S. from the Portland area,said a friend told him,that the Cherries(talking about the bush ones from the U. of Saskatchewan)can be grown in this area,but need some kind of cover during the rainy time.
It may be difficult to do that with a big tree. Brady

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Cherries are difficult here and it was a brutal late winter and spring for stone fruit. It’s rained nearly every day.

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It looks like classic Monilinia damage. It’s likely to spread with rain/wet weather during the bloom, which I guess is quite common in PNW.

Hmm, a maximum of 3 to 4 hours of sunlight per day is not really enough, and may be the source of your problem.

If it’s monilinia, how should I expect the fruit to look? I do get a few cherries each year, but they are prefect - no damage or disease at all.

There is monilinia laxa which attacks the shoots and also can attack fruits. And there is monilinia fructigena which leads to rotting fruit.

Even with monilinia laxa you can have infections in the shoots without affected fruits (on healthy limbs that is of course).

The one thing that makes me wonder if it could be monilinia laxa is the fact, that in your tree affected shoots seem to have healthy growth at the tips. I’m almost sure that wouldn’t be possible if monilinia is the culprit, cause with monilinia laxa the shoots get clogged inside by the fungus and the sap can no longer reach the shoot tips. Typically the shoot will die from the tips downward until the infection is stopped by the tree itself or a pruning shear.

Everything else looks exactly like monilinia laxa symptoms. But if the shoots resume growing I think you need to rule out monilinia infection as your problem. Sorry if I did lead you the wrong way. Didn’t realize the new growth comes from affected shoots.

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As you say, it cannot be monilia (I think it’s called European brown rot in US) the shoots would be gone for good/dead. It must be the lack of sun

My tree looked like this this year and I think it was Monilinia laxa. The infection first enters through the flowers and if conditions are not favorable to spreading, it stops there. You will get a lot of dry dead flowers and long bare branches without leaves where the flowers were before. If the weather is wet and support the infection, the top shoots can be affected too. Shoots on apricots and A. plums also can suffer. Surprisingly sweet cherries are very resistant to Monilinia laxa. My sweet cherry which is very close to the diseased sour cherry have no any problems. I think in the future I will look for the dukes e.i. sweet and sour cherry hybrids, to see if they are more resistant.

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