Montmorency leaf problems

Hi guys, first time poster but long time lurker. I really love this forum and all the info here, hoping someone can help me with my problem.
I’m suddenly having trouble with my 3-4 year old Montmorency cherry tree and after scouring the internet and this forum I’m no closer to solving the problem. I’m hoping someone more experienced can give me some feedback. Living in zone 4.

Basically only the leaves on the branch tips seem to be curling/distorting and some are showing a bit of light green/yellow mottling.

Some points that might help:

  • The tree is on a slight slope, so drainage is good (maybe too good).

  • There are no other obvious issues with the tree, ie. cankers or fungus, etc.

  • The tree put on a ton of new branch growth this year, but almost no fruit. I’ve recently pruned back a fair number of these new branches.

  • It has been very dry recently. Since the tree has been in the ground for a year I haven’t been watering it as much as I probably should be. When I checked last week the ground 2 inches deep was bone dry. I’ve since given it a deep watering (hasn’t resolved the issue though)

  • The tree has been relentlessly mauled by Japanese beetles.

Could this be a symptom of stress, or water or nutritional deficiencies? I really hope it’s not some nasty disease. I love my cherry tree…

pics included:

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Maybe powdery mildew?


I’m thinking the same thing, mine looked similar to that and then eventually got a white chalky look to the bottom of the leaves.


Thanks guys, appreciate it. On closer inspection there definitely was a white chalky substance on the bottoms of the leaves.

Do you have any good treatment advice?
I’m thinking an application of lime sulphur, and trimming out, and disposing of the infected leaves?

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idk. you said its been very dry. I’m in a fairly high rainfall area in the same zone and my mont. or any of my prunus trees, never got mildew here. when was the last time you fertilized it? all that new growth sucks up the N. maybe why the new growth is showing a deficency. id try a a gallon mixed with some miracle grow and see what happens… don’t give it any granular this late in the summer as it won’t have time to harden off for winter. maybe still spray it with lime sulfur just to cover the bases.

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welcome to the forum by the way. :wink:

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So far I have been ignoring mine :laughing: I think you can spray with milk or oil effectively. If I recall correctly, many sprays only prevent powdery mildew but do not cure it when PM is present, so be sure that you use something to treat it. I do not think that you need to cut and destroy the leaves, the fungus is ubiquitous. It mainly impacts young foliage.


Powdery mildew is relatively easy to treat. I usually use oil but many things work on it. I would just spray once or twice and you should be good.


I spray myclobutanil for cherry leaf spot here, that seems to keep the PM in check as well.


Sometimes I throw a little sulfur dust in with my insecticide spray - doesn’t take a lot and seems to stop it pretty quickly.

First time my apple got PM i practically panicked! Covered the sick part with a plastic bag and cut it off, took it straight to the garbage. But generally now the tree will just outgrow it, sometimes with a little help.