Cedar-Apple Rust
Bright orange to yellow-orange spots on apple leaves and fruit, each with tiny raised black dots in the middle and short fungal tubes hanging from the underside. It needs a juniper or eastern redcedar nearby, which grows brown woody galls that push out orange gelatinous horns during spring rain, and that two-host pairing is what separates it from ordinary rust on other plants.
Disease checklist
Four things to look for. If most of them match what you are holding, you are in the right place.
What gets rid of it
Gentlest option first. For most backyard cases the first one is enough, so try these in order and stop as soon as it works. If you do spray something, the product label tells you how — please read the notice further down.
1Cut the galls off the cedar
In late winter prune the brown woody galls out of nearby junipers and redcedars before they turn to orange jelly.
pole pruner sawTry this first2Separate the two hosts
When planting new apples, put several hundred yards between them and any juniper or eastern redcedar you can control.
3Plant resistant apples and crabapples
Choose cultivars listed as rust resistant, such as Liberty, Enterprise or Freedom apples.
cedar apple rust resistant apple tree4Preventive fungicide at pink through petal fall
Myclobutanil or a labelled rust product applied on the schedule the label gives, starting before symptoms appear.
myclobutanil fungicide5Accept it on ornamentals
On crabapples and hawthorns grown for looks the damage is mostly cosmetic and no spray is needed if you can live with early leaf drop.
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Which plants get cedar-apple rust
Every plant we cover that gets cedar-apple rust, grouped by type — tap any one to open its page. A note beside a plant came from that plant’s own entry, because the same disease can be a minor nuisance on one plant and a serious problem on another. Plenty of plants we do not cover get it too.
trees6
Plant families hit hardest
Related plants often share the same problems, so if one plant in a family has it, check the others. The largest group here is Rosaceae, with 9 of the 11 affected plants.
- Rosaceae9 plants
- Cupressaceae2 plants
When to treat
Protect the apple or crabapple from pink bud through about two weeks after petal fall, when the cedar galls are releasing spores; once the orange spots show, spraying that leaf does nothing.
Timing only — the label is the law
This page tells you when to watch for cedar-apple rust and when treating is worth considering. It is not a recommendation to apply any particular product. Read and follow the product label before you spray — under federal law the label is the legal instruction, and using a pesticide against it is illegal.
- Check the pre-harvest interval. Every product that’s cleared for an edible crop sets a minimum number of days between spraying and picking. Find it on the label before you spray anything you intend to eat.
- Check the re-entry interval before you or anyone else works in the treated area again, and use the protective equipment the label names.
- Confirm the product is registered for your crop in your state. This page groups many different crops together, and a product legal on one of them is not legal on all of them — state registrations differ too. Your state pesticide agency or local extension office can confirm both.
- Rates and mixing instructions come from the label, never from us. We don’t publish them because they differ by product and formulation.
Other problems on the same plants
If a plant gets cedar-apple rust, these are the problems it most often gets as well, so they are worth checking for while you are out there. They tend to appear together; one does not cause another.