Can anyone help me identify what is wrong with this apple tree and how to cure it. Most of the leaves have these. Yellow/orange spots on top and growths on the bottom of the leaves under those spots. I took the best pictures I could with my phone's focus. My best guess from research is cedar-rust. There are definitely a lot on the property, but none nearby. Didn't notice this in the spring when I mulched and fertilized.

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1 Answer 1


I'm afraid it is Cedar Apple Rust, the common term used for Gymnosporangium juniperi-virginianae, a fungal infection which requires both apple/crabapple and juniper plants to complete its life cycle. There aren't really an ideal solutions, nothing that will kill it off, so the usual course is to keep a check on Junipers and prune out any galls seen before they get to the orange, gelatinous stage and ready to disperse their spores.

Now you've got it, you will need to carry out preventative measures, such as checking the junipers, possibly even removing them, sweeping up and clearing away any leaf litter from them and the apple trees, using preventive fungicidal sprays, which may give some control. More info here https://www.planetnatural.com/pest-problem-solver/plant-disease/cedar-apple-rust/

  • Will this kill the tree, this year, or will it just set it back? Does it repeat the following year, or can I start an anti fungal regimen next spring and not have to worry about it. Thanks.
    – Dalton
    Jun 28, 2017 at 18:49
  • Unlikely to kill it, but it won't be terribly healthy and it may affect fruit production. Now you've got it, you will always have to worry about it and take evasive action - its a never ending two year cycle all the time you've got both apple and juniper in the same area.
    – Bamboo
    Jun 28, 2017 at 19:52
  • I've been having trouble with it for a long time. I might just rip it up and replace it with a resistant tree. It's only about 3' tall. Had it for several years and it's been one thing after the other. Inch worms, this, something else. I've got aphids on my other one I have to take care of.
    – Dalton
    Jun 28, 2017 at 19:53
  • Well its a thought, but bear in mind 'resistant' doesn't necessarily mean impervious or immune... if you take that one out, might be worth waiting a year or two to try to break the existing cycle.
    – Bamboo
    Jun 28, 2017 at 20:15

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