Apple tree dropping leaves

I have a SUNDANCE apple that’s supposed to be resistant to apple rust but this picture sure looks like what I expected rust to look like. I included pictures.
The tree is situated between a Pixie Crunch and a Honeycrisp and they look normal so far.
There a lots of yellow leaves on the ground and it happened very suddenly.
Ideas welcome and appreciated … I don’t know how much to worry.

No thats apple scab, not rust. If any tree will have CAR it will definitely be the Honey Crisp.

Since Sundance is a scab resistant variety very likely your tree is not Sundance.

If you get enough dry, warm weather your tree will be fine through this growing season. If you think damp, cool weather is likely you should begin spraying a fungicide that is registered for Scab otherwise it will continue to spread in the tree.


Just curious is there anything he can do now to help the tree?

I was editing my post as you were typing.

1 Like

Product contains myclobutanil like Immunox can help with both Cedar Apple Rust and apple scab.

Captan works, too.

Ah crap. What I bought was supposed to be a Sundance and last year (the first year it produced) it looked like a Sundance apple.

As for a fungicide, I happened to buy Immunox for the grapes and I believe that’s okay for the apple. I’ll have to check the label but I think it can be used for scab and rust.

From what I’ve seen , scab doesn’t kill the tree (typing with crossed fingers is tough) but can weaken it.


I should have read your comment before posting my reply to TCT.
Thanks mamu.

Captan will not control CAR.

I use captan but usually as a fill-in between more, um, “robust” sprays.
I wouldn’t have depended on captan as a main fungicide for something like this.

Agree. I meant to say Captan for scab. Immunox for both.

Could be scab or frog-eye leaf spot (black rot) - can’t tell for sure without a close up. Black rot is less widespread but I get it quite a bit due to uncared for neighbor apple trees. I think in either case the remedy is a fungicide. I would go with captan and/or immunox.

What I said before was wrong.
I have Mancozeb, not Immunox.
The Mancozeb label doesn’t list apples.
I assume Immunox does?

But here’s what’s curious about this whole affair … I had just used Bonide Fruit Tree Spray on the apples a day or so before the leaves started showing the problem and dropping.
The Fruit Tree Spray product is listed as effective against frog eye, scab, and rust.
Maybe the application was too late.

While Bonide Fruit Tree spray is used by many people, alot of people find it to be too weak to provide good disease control.

Sounds like the disease was already established before your spray.
Captan is the fungicide in the bonide product but as TFT says the concentration is weak.
But I have seen captan recommended for black rot.
Immunox is listed for Apple scab.

I did not look up sundance to see what is claimed about it’s resistance to scab but I have done so for a lot of varieties. What I have found is, first** resistance seems to be subjective in it’s use / claim .** Some varieties are listed as resistant from one study and listed as susceptible in another. One more thing is resistant doesn’t mean immune and that makes evaluating a variety even more confusing. A resistant variety may not have any issues in one area but have issues in another.