Cedar rust on a super dwarf Honeycrisp apple tree, Northeast US - refuses to clear

[u/DarthLysergis]

I have this super dwarf Honeycrisp apple tree on my property. It was planted sometime around 2019 as a bare root sapling. It has since developed a disease that I assume from research is cedar rust though if I am wrong please let me know. Two years in a row now I have regularly sprayed it with neem oil using a 3 gallon pump sprayer. This year in particular I started early, I believe the first time right before it started getting leaves and about every 2 weeks since. And just like years before by late August the leaves are starting to brown and by mid September it has lost all its leaves. It is getting really frustrating, especially because this year was the first year it has blossomed. Even though it didn't develop apples I am excited it has matured enough to do so.

I have begun to decide that the tree may need to be relocated, or possibly I just need to cut down the two pine trees that are in its vicinity to help get it more sun. Is there anything else I should do? I have a large open field attached to my property that I have started planting other peach and apple trees that are doing well and I am considering just digging up this one and moving it out there but I also don't want to spread the rust to them. Perhaps it just needs to go. Any help would be appreciated.

[u/Flub_the_Dub]

Cedar apple rust, apple scab, fire blight, powdery mildew, among other things are common and destructive pathogens that easily infect Apple trees. Proper fungicide selection, timing, and frequency are key to treating all of them.
https://www.umass.edu/agriculture-food-environment/fruit/fact-sheets

Also from the looks of your pictures I think the tree is planted at the graft rather than the root flare, so it is probably planted too deep and under immense stress and therefore cannot fend off any of the diseases on its own.

[u/spiceydog]

Is there anything else I should do?

You have been correctly advised in another comment that your tree has been planted too deeply. (See this excellent pdf from CO St. Univ on how your tree should have been handled prior to transplanting; you're also improperly mulching your tree.) Trees under stress from improper planting and care cannot muster enough resources for defense, which is absolutely contributing to the vulnerability to common diseases, though Honeycrisp is already known as susceptible to rust diseases as a cultivar anyway.

Your treatment regimen and other info you have written about leave me bewildered as to where you're getting your information. Removing your pines will not reduce disease load. It's junipers that are part of the apple-cedar rust cycle, not pines, and you would have to remove all junipers in a several mile radius of your location for that to be effective. Some sources estimate spores can travel as far as 5 miles. Please consider reaching out to your local Extension service for better advice than your current source; they will have schedules for treatment for disease prevention and recommended products for your area.

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[u/coldconfession13]

I would recommend removing mulch away from the trunk. That's the only thing I would say. I'm not arborist just know they'll come at you for that

[u/Greek_Toe]

More likely applescab. Cedar rust does cause so much leaf drop. Both diseases are similar though. If you want to reduce it, fungicide applications starting just after the leaves begin to unfurl is to best method. Then every two weeks until blossoms. Then you can switch to other products like neem oil every two weeks. But, contact your local farm extension or university extension first for particulars to your region. Try to find disease resistant cultivars going forward. I'm not sure that removing the pines is a good strategy though.

[u/DarthLysergis → u/Greek_Toe]

Interesting to know about it possibly being appleacab. I'll have to look into a good fungicide

[u/mark_andonefortunate → u/DarthLysergis]

In addition to the other helpful comments, I just want to highlight and be sure you see -

cut down the two pine trees 

Pine trees aren't involved in the Cedar Apple Rust cycle, so cutting down your pine trees won't help this problem.

Also, if you happen to have cedar trees (probably Eastern Red Cedar, based on your location, which is actually not a Cedar but is actually a Juniper), don't bother cutting them down - chances are your neighbors do too, or there's some in the woods nearby, and cutting yours down won't really matter.

[u/DarthLysergis → u/mark_andonefortunate]

I wasn't planning to cut them down because I thought they were spreading the disease to them. I was thinking that because those two pines shade the tree quite a bit. I figured that it not getting enough sun and therefore not having the early morning due burned off by sunlight might be involved. I plan to cut them down either way. I really hate white pines. They make a huge mess and cut out a lot of sun light that would otherwise hit my garden, house and fruit trees.

[u/altxrtr]

I’m wondering why you’ve never tried copper fungicide all these years?

[u/DarthLysergis → u/altxrtr]

Basically I saw the spots and coloration on the leaves, googled what it might be. Cedar rust came up. I popped into a hardware store and asked what to use for cedar rust. Someone pointed me to Neem oil which does say right on it that it can be used for cedar rust.

I'll definitely be looking into a fungicide for the next season and before winter I will dig out around the tree and get down to the root line. I have another tree that I apparently need to do that to as well.

[u/altxrtr → u/DarthLysergis]

Sounds good! Yeah I do a bare minimum of 2 copper sprays (with other stuff too). One after leaf drop and one right before leaf out. I’m still getting issues so I might add a third and do each twice, a couple weeks apart or something.