There are some fruits like juneberries (at least the native species) that I can’t grow here because cedar rust ruins practically all the fruit every year. I don’t have enough experience yet to know how medlars will be, but it seems cedar rusts could be a major problem with medlars, too. I have red-cedars all over and around my small farm, so there’s no way to get very far away from them, but I just got to wondering if more minimal isolation would help at all. I might be able to get 400’ from the nearest red-cedars, but I don’t think I could do any better than that. Do you think that would help minimize cedar rust significantly? Or is that not enough distance to be worth any consideration at all?
If they are thick in the area to spores will go for miles. Plant resistant vetietys or spray .
39th, I’ve read various numbers, some quite different from others, but I’m starting to wonder what the basis for the claims is, and I’m wondering about the details. For example, even if spores can travel for miles, is it not the case that the further they travel the more they’re spread out? Does that ever translate into reduced disease? I’m thinking there probably isn’t just one distance that matters but a range within which infection gets marginally worse before reaching maximum potential. In other words, spores can travel X miles but infection gets exponentially worse up to Y feet, at which point getting any closer doesn’t make things any worse. Does that seem reasonable? Are you or anyone else aware of scientific or even anecdotal evidence that would answer any of the detail questions?
“The answer, my friend, is blowin’ in the wind.”
; -;M
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“You don’t need to be a weatherman to know which way the wind is blowin’”.
“Rust Never Sleeps”
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My orchard is on a mountainside 1,600 ft above sea level.
Do rust spores stay down mostly in the valleys, or do they climb into higher elevations indescriminantly?
I’m not sure about the impact of elevation, but I believe a good buffer is about a mile.
At one point in Virginia history a law allowed an orchard owner to cut down cedar trees on land he did not own up to 2 miles from his orchard to reduce Cedar Rust
With apples a few hundred feet seems to be a lot better than 50 feet from my experience.
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Fwiw I planted some apple trees 40’ from a row of cedars before I knew what car was. Big mistake, some trees eaten up by car
I also planted some 100 ft away. They’re affected by car but the trees live.
Also planted some apples at an office building with only scattered cedars around, the closest being maybe 200 ft away. No car in 5 years.
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All I know is that I’ve looked and looked for cedars near me and I’ve never spotted a single one. But yet the spores are here. I suppose there could be one hiding around somewhere, but I’ve really looked hard.
Jeff,
You’re scaring me.
Do you have Serviceberries near you? (aka Juneberries aka Saskatoons)
I think they can host rust spores.
Apparently some hawthorns are hosts too:
http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/cedar-apple-and-related-rusts
I’ve seen cedar apple rust…i use to spray…now i don’t care… does it really hit yield enough to make difference for the home grower?
Matt, I don’t believe serviceberries and hawthorns are alternate hosts for junipers/red-cedars but rather alternate hosts for apples, etc. In other words, I don’t think you could have CAR with just hawthorns and apples, for example. That’s how I read it anyway.
Cousin,
You might be right. I haven’t studied the issue in depth. I have none of these plants anywhere near my mountain orchard.
My backyard in the city is a different matter. They’re everywhere!
The original question is “is 400 ft worth anything”, and I believe pressure will be less than with 200 ft. but I’m in agreement with you that there can be quite a bit of pressure when there’s nothing nearby at all. However, I used to manage trees on a site where there was an apple orchard proper on one part of the acreage and a few apple trees on another section that had cedars within 150 ft of the trees and the difference in pressure was pretty apparent.
I’m not sure how much difference a 400 foot buffer makes in the transmission of the disease, but I found some interesting facts that may be useful.
The original Virginia law allowed for the removal of Cedar tree within 1 mile of an apple orchard. A few year later the law was revised to 2 miles. A few years after that, West Virginia established a law requiring a 3 mile clearance. Since the distance was increased from 1 mile to 3 miles, It looks like the spores have the ability to travel a very long distance indeed. I remove all the cedar tree I see on my property, but I see a few on my neighbors property. I’m not sure how much removing the cedar trees really helped me.