I am going to assume you didn't know about Cedar Apple Rust before you planted the trees, but just for the benefit of others who might be wanting to plant apples or crabapples, the best advice is to think long and hard before you do it. Because cedar trees are widespread in our state and very invasive, it is very hard, if not almost impossible, to grow healthy apples and crabapples here. I love apples, but have lived here for 10 years and never planted one because I don't want to deal with cedar apple rust.

Since you've already planted the trees, though, you have to deal with it. So, in answer to your questions:

I don't think it is possible to control it on the cedars themselves. What you can do is remove the cedar apples (the fungal growths, also known as galls) before they form horns. If they have already formed horns it is too late. And, if there are cedar trees within about 2 miles of you, the disease can be carried through the air, so removing the cedar apples from the infected cedar trees near you may help a little, but it won't prevent airborne cedar apple disease spores from infecting your plants.

You can spray your crabapples with a fungicide that is labeled for use on crabapples for the prevention/control of cedar apple rust, but the spraying has to be done at very specific temperatures and at very precise times. I believe the spores transfer most readily when temperatures are in the 60s. The fungicide most readily available to homeowners for Cedar Apple Rust on crabapples is cholorothalonil, most often sold as Daconil, and often used by vegetable gardeners, for example, to prevent Early Blight on tomatoes. I think you also can use a different fungicide called Bayleton. Just read and follow the label directions IF it is not too late, weatherwise and temperaturewise, in your area. Even though your crabapple trees are new to you, they actually are several years old by the time you buy them, so the application of a fungicide following label directions should not harm them at all. Just be sure you dilute the fungicide and apply it as directed.

The entire life cycle of cedar apple rust from cedar tree to its transferrence to apple trees takes almost 2 years. It is an ever-present threat. It is the reason you don't see vast orchards of apples in Oklahoma. Of the two crabapples you plante, I think Prairiefire is considered highly disease-resistant and Profusion less so. However, disease-resistant only means the tree has some resistance, not immunity, and even disease-resistant trees can and do get diseases.

Cedar Apple Rust is the main cause of rust on apple trees, but you also have to watch out for the closely related Cedar-Quince Rust and Cedar-Hawthorne Rust. They are controlled/prevented by the same fungicides. Please understand though that even the regular application of fungicide is no guarantee the trees won't become infected. Understand also that cedar apple rust is not something that will be a problem only once. If is an issue for your trees one year, it probably will be an issue for them every year when the temperatures are in the precise range that allows the spores to transfer and infect apple trees.

Only you can decide if you want to deal with the cedar-apple rust disease every year, or if you'd rather cut your losses and replace your crabapple trees with some other kind of tree that is more disease-resistant.

Good luck,

Dawn

Here is a link that might be useful: Info on Cedar Apple Rust

Thanks so much. We've lived here 2.5 years now, and this is the first we've seen of this nasty (alien-looking!) affliction.

The flowering crabs aren't for fruit production, but just for show. I understand the CAR causes premature leaf drop, and I suppose that's more what I'm concerned about.

The cedar is *tall* and there's simply no way I could remove all of the spores. They've already begun to drop, and already have the ugly tentacle things.

Would cutting the cedar tree down do any good at all?

You might not have seen CAR before because no one has apples or crabapples (or hawthornes or quinces) around you. For the CAR to complete its life cycle, you have to have both cedar trees and apples/hawthornes/quinces.

I know the crabapples are for show and not for apple production, but they are not likely to be too showy with CAR.

Cutting the cedar won't buy you much, if any, relief as long as there are other cedar trees within two miles, especially south, of your trees. Even if you cut your tree, any other cedar tree in the area can infect your tree with airborne spores.

The best you can hope for, I think, is to spray your trees with Daconil every year and try to keep the disease's impact on the trees to a minimum. It is likely that your crabapples will eventually be infected with CAR and have to be removed. Prairiefire probably will be able to fight it off longer than Profusion, but not necessarily forever. One other thing to watch is your fertilization. Apple and crabapple trees that are overfertilized are much more susceptible to cedar apple rust and the reason is that overfertilization weakens a tree and that makes it more attractive to fungal spores.

I have never seen a crabapple tree, and precious few apple trees, growing here in Love County and I am sure the cedar trees are the reason why.

Dawn

Forgot to mention, we're in Edmond/Oklahoma County.

It could be that you've never seen it before because you just weren't looking for it, you know. I don't think your tree somehow brought the cedar apple rust out of dormancy, but I'm not an expert on cedar apple rust. More than likely, the cedar apple rust was there all along and just happened to reach the point in its life cycle where the galls are forming and releasing spores. Your neighbor's trees have been there longer, and you can blame the CAR on them if you want. If there weren't any apples in the area, the spores wouldn't be able to continue their life cycle, so the disease would go away. Now that y'all have apple trees near cedar trees, it is going to be a vicious cycle.

You know, there is a chance your trees won't be affected, especially if the temperatures have been in the right range there and you can spray with Daconil before the crabapple trees are affected. What Daconil does, essentially, is act as a 'sealer' to keep disease spores from settling on the leaf surface, so be sure to spray the tops and bottoms of all the leaves.

I have a different take on flowering trees that I learned from the great Texas gardening guru Neil Sperry, and I've heard him preach this philosophy a billion times. He recommends that people plant a good-quality tree that looks good pretty much all the time (even when dormant) and not a flowering tree that looks good briefly--normally for 10 days to 3 or 4 weeks depending on the type of tree--and doesn't look that great the rest of the year. It is something to think about and Neil (as always) is right. Lots of people plant spring-flowering trees just to have that 2 or 3 weeks of blooms, but the trees aren't often that well-adapted here, struggle in our heat, have disease issues or are short-lived.

If I wanted a flowering tree in my yard, I'd probably have planted a crape myrtle. There are lots of good ones, they come in all sizes and many colors, the newer ones have a lot of disease resistance bred into them, and they go in and out of bloom repeatedly throughout the growing season. So, if the crabapples, don't make it, you might want to give crape myrtles a try.

Okiedawn, I so, so appreciate your thoughtful and informed responses.

I love crapes, and have several. I really intended to plant 3 more crapes, but thought I was overdoing them, and wanted something just a bit different. However, they're steady and reliable performers, and will definitely be my "backup" plan.

Our neighborhood has roughly 2 miles of greenbelt trails. I'm going to take walk and see how many cedars are around, and also take a look at the other crabapples around. If they're really miserably failing, then I'll toss them and revert to the ol' standby crapes.

Thanks again for your time and food for thought!

Reno fan,

You are so welcome.

Sometimes it is hard to tell someone that the trees they planted are looking at the prospect of serious trouble from day one, but I try to tell the truth as I see it or as I understand it. It would be easier to sugarcoat a situation, but it would feel dishonest.

In the case of your crabapples, I hope I am wrong. However, the link between cedars and apples (and their relatives like hawthorne and quince) has been studied extensively and the effects of cedar apple rust on apple/crabapple trees is well-known.

I haven't seen Brian online this weekend, but he might have something to say about your crabapple trees and CAR the next time he's online. He just planted a lot of fruit trees himself and I suspect he has researched CAR even if he hasn't encountered it himself in his previous landscapes.

I'd dearly love to grow apples and crabapples, but I just won't plant something destined to suffer CAR in a state where the cedar trees outnumber the human population. (The last figure I remember seeing was that at least 3.5 million ACRES of cedars existed in Oklahoma in 1985, and I think I read that way back when we moved here in 1999. At that time, the estimates were that we'd have 8 million acres of cedars by 2004. Here we are in 2009 and there's no telling what the number is now. I am certain there's not 3.5 million or 8 million acres of apples/crabapples in our fine state.) So, guess who wins the Ceadar-Apple Rust battle.....well, clearly not the apples.

Dawn

Is it possible for the cedar to have the disease without us seeing it? The stupid tree is *huge*, leans over our pool, and is smack dab in the middle of the yard. We've had to stare straight at it since we've moved in, and have also had to limb it up to be able to walk on the deck around the pool.

While the tree may have had other symptoms I'm not familiar with, I know for certain it hasn't ever had the "alien pods" before this year.

I suppose I'm really wanting to hack the horrid thing down anyway. (The only reason we've kept it this season is because it provides a modicum of privacy between the pool and the greenbelt walking trail behind our house.)

Truly though, it may have to, uh, accidentally fall over in the next wind storm. ("Gee dear, I'm not sure what happened. One minute it was fine, then it just fell over....)

I don't know if you could tell if the tree had the disease before the galls erupt or not. I've never seen cedar apple rust here in Love County but then I've never seen an apple or crabapple tree here, and the fungus has to have both kinds of trees within 2 miles of one another in order for it to survive. It is possible the tree was infected by the fungus before but that it didn't have anyplace to go when the galls formed and began shedding spores, so the disease essentially died at that point. Now that apples are nearby, the fungal spores can migrate from the cedar to the apple trees and can complete their long life cycle.

Here's my take on cedars: if you are at all in an area where grassfires or wildfires are somewhat common, get rid of the cedar. Cedars burn like mad and once they get hot enough, the limbs essentially can explode and send the burning resinous sap through the air. The burning sap can spread the fire to structures, other cedars, dry brush or grasses, etc. It is advisable to remove all cedar within 100' of your home for fire control purposes, and 300' is even better.

In addition to the fire issues, cedar is incredibly invasive and also is a huge water guzzler, robbing nearby plants of moisture.

There--that gives you some ammunition for getting rid of the tree if that is what you want to do. : )

Dawn