Pear tree Fireblight research so you dont have to

You forgot to ask the question!:slightly_smiling: Ask away one of the moderators will move it to a new home if they think it fits somewhere else better.

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I flagged the moderator for you. Hope one of the mods will help you with posting new topic.

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Thanks to all for the replies.
I believe this is the correct thread so I’ll ask it here.
A brief background … I lost a Clapps Favorite to Fire Blight a couple of years ago.
I still have a Flemish Beauty (also highly susceptible to Fire Blight) and an Ambrosia left.
I can’t find anything related to F.B. susceptibility for the Ambrosia but I’ve been spraying them both with streptomycin this season.
Now the question. They’re both in the early fruit forming stage and I’m wondering if there’s a point at which I can stop spraying. They both have maybe 3/16" or larger fruits right now.
I’m worried about the Flemish Beauty and I’m not at all sure when I can stop worrying … if at all.
Thanks so much.

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Bubbagone,

I hope you’ve learned a little more how to tool around this site. It took me a little time, but if you stick with it, it gets easier.

I’m not a big pear guy, but I’m pretty sure I remember reading ambrosia is somewhat resistant to fb.

Once bloom is complete, it doesn’t help to keep spraying bacterial compounds

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Now THAT is good news.
I wasn’t sure if the blossoms were the only way the bacteria could enter.
I think I did read something about penetrations through openings in the bark.
In any event I think the Ambrosia will be okay but I’ll be watching and hoping the Flemish Beauty makes it.
Thanks for the info.
I do have a few more things that have been eating away at me so I think I’ll look for the right threads to pursue them.

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Fireblight attacks growing tissue so the only time we are really safe is winter. That’s important because canker in stone fruits like cherry, peach,and plum is always active. The bloom stage for pears is very dangerous because the blooms grows very rapidly and insects go from bloom to bloom spreading the disease. Fireblight is at its height when its wet and warm. 65 degrees give or take and 65 percent humidity give or take is perfect fireblight weather so for us that’s spring. Our summers July and August are hot but dry so FB does not spread much. Insects eat foliage and birds fly tree to tree so don’t rul it out. Like Olpea said spraying antibiotic past bloom won’t help and once the fruit develop the tree sealed those open flowers. Open wounds and fast growing tissue are the things to watch for now. FB strikes typically tips of branches during this time and amputate below those strikes as fast as you can.

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There is a new pear resistant to fireblight and other diseases, my friend just bought it from Bulgaria about 14 days ago. I wouldn’t be surprised if it made it to USA in the upcoming years

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Never heard of that pear Paul. It may take a few years to make it here.

Ambrosia does have some fireblight tolerance as mentioned. The full description can be seen here https://hort.purdue.edu/newcrop/ambrosia.pdf

That Ambrosia pear has some pretty good ancestors. Has anyone tried this pear yet?

@clarkinks I don’t see Harrow Sweet on the USDA list of FB resistant pears. Was it introduced after the list was compiled? Edit: Now I see another thread saying Harrow Sweet is not very blight resistant, so that answers that question. I was about to graft it for a friend, glad I checked!

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Just depends on the strain of fireblight i think. Here harrow sweet has done fine so far but other places have problems. Its on probation here for now. I grow a couple of trees only due to the same reasons you mentioned about concern of disease @hambone. If you taste the pear you will see why you should try one anyway.

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I’m north of most folks, so the 65 and 65 thingy at bloom is not common here (PEI).
Having said that, I have 30+ year old pears with no fireblight. They are Minie, Menie, Patten and Bosc.
There are two Abate Fetel seedlings, 3rd leaf, and a Bosc seedling about 10th leaf, so far also without fireblight. I have 15 year old Red Clapp, free of FB too…so location matters, grin.

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Yes you really have the fireblight bacteria at a disadvantage there. It does not like the cold one bit. Like i said previously its only active in growing tissue. If does not always wait for 65/65 conditions but generally in its ideal world those are its preference. I would not graft a lot of new wood because remember there are many strains of fireblight. Honeybees start flying at 50 degrees so you have the upper hand for sure.

Our ‘Honeysweet’ pear has got fireblight for the first time ever, it’s resistant against it, the tree appears to be getting the blight from the leaves as insects chew on the leaves, if the leaves have more than a tiny bit of blight infection then it spreads to the tree, that happens slowly. It’s in it’s 6th season.

Our OHxF 87 root stocks, the leaves are way more resistant against fireblight yet some of the leaves are getting it as well, yet the OHxF 87 trees themselves do seem immune from the disease, there was a whole cluster of leaves on one of the OHxF 87 root stocks, that were all infected with fire blight, yet no fire blight in the tree it’s self. So I am wondering if anyone on here knows of any pear variety/anything related to pear that appears to have an immunity to blight that prevents the leaves from getting infected.

By the way our neighbor does have a huge flowering pear, probably a Bradford since they are so common here.

PS:
The OHxF 87 root stocks did not flower yet.

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In the next year or two… I plan to try starting at least a couple pear trees again…

At my current location, I have started 6 varieties of Pear… and they all died of FB… + 2 apples died of FB. I had a actively growing and huge bloomer (bradford pear) near by… which is going to be cut down, removed completely this fall, or early winter. I hope that helps with my FB issue.

At the location where we will be building a new home… no bradford pears (nearby)… a neighbor across a big hollow 1/2 mile or so, has a bunch of douglas pears… I hope they don’t haunt me.

Anyway… with my past of FB… I want to try Pear varieties with the most Resistance to FB… getting one to live and produce is the main objective… fruit quality would be nice, but living and producing first.

I started to plant some a couple years ago, down a ridge from my home, in a separate location… but I never got that project done… (planted something like 9 fruit trees that spring, and 24+ berry bushes). Just got too busy.

The varieties I had selected to try are…

MoonGlow – Univ Tenn website shows moderately resistant to FB
Seckel… again Univ Tenn website… MR to FB.
Blakes Pride – not mentioned on UT Site… but in OGW catalog… they say FB resistant

One other variety mentioned in my 2020 OGW catalog… Surecrop.— and positives mentioned resembles bartlet in flavor, consistent bearer, “prolonged progressive blooming - ideal for late frost areas” and very FB resistant.

I also plan to learn grafting this fall/winter… and get some FB resistant rootstock and graft some (old home site pear scionwood) myself. I expect these may be Kieffer Pears… They make great pear preserves. I know where 2-3 are that I can collect scionwood from.

I do have aweful late frost issues, so that Surecrop, with the prolonged bloom has my attention.

Anyone here tried that variety ?

Anyone here have serious FB pressure, and have has success with Pear varieties ? I would appreciate hearing about it.

Thanks

TNHunter

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What pear varieties did you lose to FB? Do you have a slope to avoid some late frosts?

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My last attempt was back around 2014… and the varieties I can remember trying include bartlet and andjou ? There were others… I might be able to recall if they still carry them. I will check their website when I get a chance.

My orchard is on a ridge top… slight slope to south east… with deep hollows nearby. From my ridge top orchard you can go 100 yards north or east and drop 150 ft in elevation.

TNHunter

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You could grow a base of these to have a good FB resistant tree that you could use for processing and then frankengraft some things onto them.

Moonglow has been a FB magnet for me. If you aren’t in a rush for pears, you could get Warren instead.

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I have observed Orient for over 40 years and it has had good resistance to FB.

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