Rust Prevention/treatment Suggestions

Hello Everyone,
Up here in southern NJ CAR is a bit problem. I have some trees that are supposedly CAR resistant and a few that are not. Of course the non-CAR resistant strains are showing heavy rust due to our unusually wet spring in spite of my spraying. So my question is two fold:

  1. What would you suggest I spray with next year to combat this perennial thorn in my side. (something that will not affect pollinators please)

  2. How should I treat the currently infected trees?

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I use Serenade in early spring. It is not perfect but I believe it helps.

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I use Immunox and have good results, given that my lot has about 50 juniper trees on it

Timing of the spray is important - you want to spray when the cedar galls get all jelly-like. This can sometimes happen more than once in a spring


A second vote for immunox as a preventative. I used it last year and had very little rust. This year I skipped it and the CAR is terrible on my most susceptible trees.


Thank you for the suggestions everyone. I think we might have had more than one bloom of CAR this year and that is what got me into this predicament. I sprayed twice after I noticed the jellies but still got hit pretty hard. Since my trees are young I am hoping they can handle the abuse.

I used immunox and asked my neighbor check his cedar trees. He picked off and disposed of the culprits from the cedars. Cedar apple rust is an ongoing battle for most orchards.

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I have a few varieties of apples that are more prone to get CAR and I mostly treat only these. Then I try to ignore a few specs on the others. On some very good advice to me a few years ago a few spots will be ok.


On a bad year in the northeast, CAR can actually cause susceptible trees to defoliate and loose the crop, but this is rare. If leaves just have a few spots it really isn’t a problem but Immunox (myclobutanil) is the ticket- Serenade likely just won’t cut it- better to grow only resistant varieties is you are attempting to go synthetic free.

If you do only two myclo sprays, one at petal fall and one 10-14 days later, it is extremely unlikely you will have significant CAR. Even if you wait until you see some spots, myclo will arrest it. I am basing this on decades of experience and multiple sites in the northeast. My customers don’t want to see ugly spots on their trees- regardless of crop.

Of course, at some point CAR can develop resistance to SI’s (myclo’s chemical class).


Sadly the cedars are all over, my yard and others, and they are tall so I can only remove the galls that are reachable on my land. Spraying is the only option to mitigate this it seems. I do need to see what I sprayed with. I remember what the bottle looked like but haven’t gone back to look at it since the spraying.

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Same here. Removing the source trees is not feasible so resistant varieties and treating my own trees are my best options.


Yeah the only one of my trees not affected at all seems to be the enterprise with the chestnut crab coming in a close second and the granny third. My crimson crisp is almost bright orange with rust but I knew going into it that the breed was non-resistant but its one of my favorite fresh eating apples so I am hoping better treatment will help.

I occasionally get some spots on my Enterprise - disappointing because I don’t really like Enterprise much

When infected cedars are only a stones through a way a third spray right before bloom can assure pristine leaves if that is what you are shooting for.


I’m less worried about the aesthetics as much as the health and productivity of the trees but that is good to know. I worry about harming bees due to my neighbors having hives and the fact that i hope to have two myself in the future.

I sprayed for CAR several times, but see some rust spots on some variety now. Will another myclobutanil application prevent the problem from getting worse, or is it too late to do anything?

Probably where you are the season is over but an app will do no harm.

Alan is this suitable?

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Looks like the stuff. The active ingredient is myclobutanil, right? Apply it at highest legal rate.

That’s the right one

Unfortunately, Spectracide labels more than one product as “Immunox” and some of these aren’t right for fruit trees

hi thank you…anything i can do now or just wait it out till spring and use immunox then???
it has suddenly overwhelmed 20 apple trees in a couple days time