What exactly is and isn't a cedar?

I have a crabapple tree that gets cedar apple rust. In addition to spraying with an anti-fungal spray, I'm trying to eliminate the cedars nearby, but I keep getting confused about what a cedar is. Some junipers have the word 'cedar' in their name. Some arborvitaes have 'cedar' in their name. Are they cedars? Can they transmit the disease? Someone help me please! I love my crabapple, but the cedar-apple rust makes it look awful.

Harper

Here's my beautiful tree.

Gymnosporangium juniperi-virginianae is responsible for Cedar Apple Rust and my experience with that fungus is that it will only alternate between Juniperus virginiana (Eastern Red Cedar) and Malus spp.

What anti-fungal spray were you sold to allegedly "treat" this?

This reference lists the hosts, the one Equil mentioned is the most common one but there are a few others that can be hosts too. All are in genus Juniperus. The key is to figure out the Latin names of your plants, a lot of things with a common name of cedar are probably in a different genus so they won't be hosts for this. http://nu-distance.unl.edu/Homer/disease/Hort/Trees/ApCdRust.html

Great photo of the telial horns in that bottom right hand photo at your link ecrane!

Remove those and burn them or bag them and throw them out with your garbage if you see them.

ecrane, that's a fantastic link. Thanks to both of you.

Equil, I was just told to spray with an "anti-fungal" every 10 days in the spring. I bought a Safer Soap brand or something or other... the tree still suffered from the c-a rust. This year, I thought I'd try spraying it with neem oil. However, I also gave it a spraying of 'Messenger'. I'm drawing strings here. Ideally, I'd like to not have to spray it at all. When I first planted the tree, there was an eastern red cedar on my property, and one in the property behind my house, both have since been cut down (sorry birds!) Now there are no eastern red cedars that I can see in the neighborhood.

Harper

Which Safer Soap product did you try? I don't believe Neem will be effective against this. I doubt very seriously if one application of Messenger, a harpin protein, would do much other than to maybe stimulate some of the plant's natural defenses which might ward off a secondary infection. Don't get me wrong here, Messenger is a great product but I get the feeling it's not going to be of any help to you for this situation.

I've not known much to be effective other than the planting or resistant plants combined with the removal of all hosts in the immediate area and even then the spores can travel for miles so you'd have to go around removing eastern red cedars (and the others mentioned by ecrane) from a 5 mile radius of your home and that's sort of impractical and probably wouldn't put you high on any popularity list with your neighbors. Resistant doesn't mean that a plant won't ever contract Cedar Apple Rust.

I don't know if you were told to begin spraying fungicides before budbreak but that's when you'd have your best shot at control. It's a perennial disease on your Crabapple and an annual on the Eastern Red Cedar which means you will have ongoing issues. Other than that- if the humidity is real high and if it's been raining a lot, I'm told you need to space fungicide treatments at 7 day intervals not 10 day intervals until at such time as the the tree begins fruiting. That's a lot of $$$ for one tree. It's been so long since I've had to deal with this and I really don't care for fungicides.

Here's an interesting link you might want to check out-
http://www.eppo.org/QUARANTINE/fungi/Gymnosporangium_junip_virginianae/GYMNJV_ds.pdf
go to the section on phytosanitary measures.

If you are going to go the route of fungicides, you might want to check out the active ingredient in any product you select here-
http://www.pesticideinfo.org/Index.html

I did a little checking for you and the chemicals that are currently being recommended for control of Apple Cedar Rust, if applied according to labels, are:
myclobutanil
thiophanate-methyl
chlorothalonil
propiconazole
mancozeb

I'm not all that comfortable with using any of those chemicals on my property. I think I'd have to let the crabapple go to crabapple heaven in favor of planting a different species before I started a management regime of weekly fungicide treatments.

Equil, you really know your stuff. You're funny too! No, I don't think the town would like it much if I cut down all the Eastern Red Cedars. I'll check out the links you posted. I just wanted to reply to you right away. Maybe the crabapple will go to heaven, but I hope by some miracle, it stays and grows into a beautiful tree. (sigh) There's no way I'll be using seriously toxic chemicals. They scare me.

Thanks!
Harper

Nope, don't really know my stuff. Only have experience in areas where I've been hit by the mack truck. I got hit by the mack truck with rusts. I'm resigned to rust because I truly have major issues with fungicides that are engineered to kill. I literally threw in the towel and gave up on rust quite a while ago because I don't own the surrounding properties within a 5 mile radius of where I garden and I'm not in a position to stick a dome over my property. I have Hawthorn trees here that get nailed to one degree or another with rust every year. Some years are wetter and therefore worse than others and the rust will be so intense it looks as if somebody blew up bright orange pumkins to smitherines around the bases of my trees. Sets the mood for Halloween I suppose.

Thank you Resin! You're right. I was so confused.

Harper