Last May I did a post on Cedar Apple Rust. At the time, I mentioned that it was a symbiotic host and that it affected plants in both the cedar/juniper families and in the malus family–apples, crab apples and the like.
In that post I showed this spectacular orange gelatinous mass hanging off a juniper–a lovely thing–and mentioned that in the following year apples and crab apples were affected. Well–here we are, one year later and here’s what it looks like on a crab apple. Not nearly so spectacular but surely disfiguring.
This is where the fungus gets a little more interesting–when you turn the leaf over and see the fruiting spores of the fungus. This is roughly equivalent to that gelatinous mass on the junipers and cedars.
As this Bulletin from Cornell’s Cooperative Extension further explains, the two fungi have a rather complicated inter-relationship. And apparently there needn’t be a year between the appearance of the fungi on the cedar and its corresponding appearance on the crap apple–they can appear in the same year according to Cornell.
The reason I’ve never treated my crab apple is that fungicide–lime sulphur spray to be exact–is supposed to be applied to the first time while the tree is still dormant in February. Think back to what you all remember about February. Rarely is there a time when I want to venture out, particularly to spray a fungicide! It’s all I can do to get out and walk the dog!
Then you’re supposed to spray twice more, at bud break and after flowering. Well, that’s entirely too much spraying of chemicals–even if they are quasi-organic–in my yard, particularly since this tree has had this particular fungus for 15 years now and doesn’t seem any worse for it. And if the time comes that it does become a problem, I think the tree will need to go. No high maintenance trees in this yard for me.
But until then, the birds do enjoy the fruits–so I’m hopeful that the tree will continue to shrug off the fungus just as the dogwood does with the anthracnose. The birds enjoy the dogwood fruits too. So there will be no spraying in this yard.