Pear rust appears to be everywhere now in 2021
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Yeah, I’ve pulled a few forming pear fruits that looked like they may be rusty.
I’m not sure I was even aware that pear rust was a thing before last year. Always hear about cedar apple rust.
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I even saw it at my sister’s new orchard recently. It came from the wild callery.
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Pear rust can be controlled with fungicides but the tree has to be sprayed at the right time in the spring, one time just before bud break and then another 2-3 times in intervall of 7-10 days.
substances such as difenoconazole, tebuconazole or myclobutanil are most efficient against rust in pear and apple trees.
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Asian pears seem to be effected much worse. Harrow Delight and Harrow sweet show no symptoms. Farmingdale or old home also do not appear to be effected. My small yellow pear is not effected. The resistance varities i mentioned are also highly resistant to scab. They are also highly resistant to fireblight.
I have two pear trees; a bartlett and a bosch. I put them in last year and they both developed rust. My apples did not.
I was advised to spray copper on them before bud break this spring (I think that’s the term) but I never got around to it (ski season). Now the leaves are fully developed. Since I’ve missed the window for application during budding, I’m not sure what I should do.
I read the missouri botanical garden article that @clarkinks posted the link to. I just walked around my house looking at neighboring trees, and I believe there is a red cedar on my neighbor’s property. Based on my reading, it seems like I should be on the lookout for galls on the red cedar and if they appear then that would be the time to spray copper. It seems like people are reporting that copper isn’t as effective as other treatments, but I don’t want to get into the more professional-grade chemicals, at least not this year.
I’m totally new to disease management … I went from having one plum tree and one fig tree that never had any diseases, to plums, figs, apples, cherries, grapes, blueberries, and raspberries … all last summer.
My questions are: do I have any of this completely wrong? Is there anything I should be doing now? Any other suggestions or comments?
Even my Harrow Sweet has rust this year (as well as my Seckel and Potomac).
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Yes copper is not very effective against rust it is highly effective against fireblight. You need to start next year with a spray specifically for rust. Immunox will do a better job but it’s not perfect. The options for home orchardist are limited but they will help. The key is to start your treatment schedule asap next year. Sometimes treating the cedar is as effective as treating the pears it takes both to make rust.
Pear Rust.pdf (194.6 KB)
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Thank you for your reply and the article, which I will read carefully later. However, I just quickly skimmed it and saw “A control for rust diseases must only be applied preventatively. Once the symptoms are visible on the leaf, it is too late to do anything about pear rust, especially once the month of May is over.” So I won’t waste any more product, especially since you say that copper isn’t very effective anyway. Time for a new plan for next year!
I wish I knew where the rust was being harbored, but this is a residential neighborhood in the city, so it’s not like I can go wandering around in peoples’ yards. I could post a message to the group e-mail though.
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Thanks for the information. Like Eric, I’ll have to treat the pears, as the cedars in the neighborhood are in neighbors’ properties. I was surprised to find rust on the Harrow Sweet, as others noted it was resistant. I think it has the worst case of the three. It’s been a cloudy, fairly wet year, so things might be particularly bad this year.
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Not much in the way of foliar rust on pear this year so far, but I noticed some juniper rust infection of fruit when thinning. Very similar to the symptoms on serviceberry: swellings/deformations, especially near the blossom end, and orange sporulating bodies. Most affected were Large Korean and Raja. Nothing terrible, maybe a dozen or so infected fruitlets per tree.
I’d been spraying Surround + sulfur this year. Perhaps that helped somwehat? The sulfur + Surround program did seem to help with serviceberries: we managed a nice crop from our little planting of Regent saskatoons—enough for a large pie—with only a handful of rust-infected berries. And this is eastern red cedar/cedar-apple rust central.
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I am seeing rust this year on my Magness and to a lesser extent on my Seckel.
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Immunox is the thing to spray for rust, usually one spray right after petal fall gives complete control. I had horrible rusts on apple pear and quince when I was organic (both CAR and quince rust), and now I have none of it.
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Thank you Scott
Scott
(just couldn’t resist)
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I skipped the fungicide in my first cover spray of the season, and that was a mistake… Would infuse be as effective as immunox?
I think Infuse has propiconazole, right? My impression is myclobutanil (Immunox) is more effective than anything else. I find for rusts and for black rot there is nothing coming close to myclobutanil.
I personally use Eagle 40EW, it is myclobutanil in a more bulk package … one container has lasted me about ten years.
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Yes, infuse has propioconazole. Immunox is not good enough for Brown Rot, and I am trying to minimize the chemical load in my sprays (that’s why I skipped fungicide in my first spray) as well as the number of bottles I have. I guess I can use Immunox in my first cover and Infuse in my second.
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I’ve been using copper for dormant and sulfur during this growing season due to Immunox “myclobutanil”, not being registered for fruiting pears. Seems to be working ok. I have not been able to find a good fungicide for pears that is registered to be used on them.
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