E.Spitzenberg was the most crippled FB magnet in my orchard, while it survived. Think I got one fruit from it before the final onslaught.
I thought it was pretty tasty, though several folks I've known who grew it said, in response to the much-touted catalog line that it was "Thomas Jefferson's favorite apple", that TJ must not have had much to compare it to.

Lucky, my Spitz was completely immune for years and then ZAP it got wiped out. Not sure whats going on with it. I re-grafted it a few years ago and its back to its perfect FB-free record again.. next strike and its out.

I just chopped my Canada Reinette at the knees and put four varieties on it. I have gotten spoiled by the huge stocks I can now topwork, the grafts take off when they have such a vigorous stock below them.

Scott

I've been seeing a lot of fireblight posts on this forum. I wonder if all of this blossom damage from the frosts has compromised some of the tree's natual defenses against pathogens. Scott, I am growing Orleans Reinette in my yard as that was my tree of choice, its starting to branch out now, but I havent read about any fireblight tendencies with this variety. I can tell its going to trail my other varieties in terms of full bloom date. The tree seems slow to warm. Its that bad huh? This is the first time im reading negativity about that variety from you or anyone else for that matter.
Are you taking it out?
Top working it?
Is it on a Geneva rootstock resistant to fireblight?

-Eric
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Here in SW Va, Diane Flynt grows antique cider vareities on a foggy, high-elevation mountainside, with lots of wet 60-degree nights. I would think that her lead varieties (link below) are less susceptible than most.

Here is a link that might be useful: foggy ridge varieties

Eric, I will probably topwork it but I am going to let it live another season. I have several apples that are similar in taste so I don't mind losing it - Roxbury Russet is one, Reinette Clochard is another. One problem with these obscure old varieties is there is little fireblight data on them, but I have personally had bad FB several times on Orleans Reinette. It gets it badly and no other apple within 50' gets anything. It has a late extended bloom, that is the main reason why it is so susceptible. You are in a less prone area for fireblight so it may not be a significant issue for you.

The rootstock is only going to help if the roots get infected, and that only happens in really bad strikes. The roots don't impart any extra resistance to the scion on top. The advantage of FB-resistant rootstock is for commercial growers, where .2% more loss is digging into their profit margins.

Scott

Scott,

I did see a massive amount of fireblight this past fall at an orchard that had Golden Russet. The entire tree row was infected. The trees were huge, old and on M-111.
It was so bad, I debated if I really wanted to pick the apples on the trees and bring them home.
Obviously I did pick them, and they were good, but I really didnt want to bring anything home that had anything to do with fireblight.
Paranoid? Yes. :)
What are the early warning signs of fireblight? Can you tell by the look of the blossom?
I'll keep an eye on it, thanks for the feedback.

-Eric
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I see now:

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REF: http://www.caf.wvu.edu/kearneysville/disease_descriptions/omblight.html

-Eric
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Any bit of that orange color, or drooping shoot tips or blossoms. Its not hard to spot once you have seen it a few times. FB presents itself in many different ways, there are shoot, blossom, and limb strikes, and also occasionally single-leaf strikes that turn part of a leaf dark brown. So, if you see one kind of strike make sure to be looking for the others.

Speaking of strikes, I need to go patrol again. After I get a big strike I do daily patrols. I am also back on a streptomycin spray program, I had stopped for a few years but will need to resume for a few years now. Hopefully in a few years with more magnets cleared out I can go back to skipping the strepto.

Scott

Scott: I am down in the fireblight capital, and still new to growing apples. I planted honeycrisp and suncrisp last fall which I now realize show up on various lists as highly susceptible to fb. Do you think I should yank them out? They are 2 year trees and I am pretty sure the are on M-111. Would another alternative be to cut them off just below the graft and graft another variety?
Also, I am considering ordering the following varieties this fall on G-11 and G-16 rootstock.

Grimes Golden
Karmijn de Sonneville
Newtown Pippen
Sundance
Hawaii
Kidds Orange Red

Do you think the resistance of the rootstock will provide adequate fb protection since these varieties are not fb resistant?

Thanks, Chris.

Chris, rootstock does nothing to protect the variety on top from strikes, it only means a bad strike will be less likely to kill the whole tree. I don't pay a lot of attention to rootstock resistance since I have not noticed enough difference.

I would not take out a susceptible variety already planted, but the minute it starts to look like a magnet yank it. I kept some magnets for years and it made my overall problem worse. Of those new varieties you list I have all but Sundance and none have been FB magnets for me; same with Honeycrisp and Suncrisp, they have not been bad. The only thing is your FB can be worse than mine and so you may want to be more conservative. Someone from GA posted this year about how they lost most of their orchard this spring. Even the worst strikes I have had have done only a couple percent damage in my orchard.

Scott

Thanks for the great info; a couple of more questions if you don't mind:

Are the varieties I listed that you grow producing well for you? I am looking for some complex, flavorful apples along the lines of Goldrush and these are what I have found so far.

Any other recommendations for varieties that get your attention when you take a bite, but are fb intolerant and will grow well in our zone? I am also looking for a few varieties on the tart side.

Also, I am thinking of ordering dwarf trees and trying the tall spindle pruning method, attaching the trees to galvanized poles, do you have any experience with that?

Thanks again, Chris.

Another question about managing fb: It appears from other comments in the forum that Kocide 3000 or

Chris, Newtown and Kidds have been fairly regular producers. Karmijn is not fruiting at all (I did have it in a too-shady spot but it has had a couple years of good sun now and still nothing). Karmijn also has a reputation of being a poor hot-weather apple. The other ones are too new to have reliable data on.

In terms of other reliable tasty FB tolerant varieties, I like my Myers Royal Limbertwig a lot, it reliably produces tasty apples every year. Roxbury Russet is very reliable for me, and is a strong sweet/tart (the only downside is it has no aromatics; it does have a lot of flavor just not aromatics). Reine des Reinettes is another good one, its something like Kidds but ripens later. It has been alternate bearing for me recently, I need to thin more. Abbondanza is also reliable and very high-quality, but I don't know of anyone propagating it. Oh I really liked Cherryville Black this year for early apples. Its another southern apple, the longer I grow apples the more I appreciate the old southern ones for the ability to take our climate and still produce a quality crop.

I don't follow any particular pruning method per se, but many of my trees are pruned very similar to the tall spindle. I attach trees to poles only when they are not angled in the direction I want, but putting a pole on each tree is an excellent approach.

I don't see all your FB management question, but kocide in the spring does help. I use agrimycin in bad years as well.

Scott

Chris, I planted a couple dozen apple trees over the last 2 years. I used a 1.375" diameter, 10.5' foot galvanized steel pole with most- I used a 7' U-post with a few of the more dwarfing rootstocks. I sank each 2-2.5' into the ground and so far they have been pretty stable.

Here's a picture of a bagged Goldrush. You can see the post in the background.

Scott, when I was looking into varieties last fall, I saw your comments on Abbondanza. I didn't find anywhere selling it, but I did find a few notes that it was susceptible to fireblight (moderately and least resistant- I know there was a 3rd article which was more explicit in calling Abbondanza out, but I can't find it now). Since you haven't had any issues with it, I've got to think that Canada and Orleans Reinette must be mega-susceptible.

But, as I haven't seen any FB yet (even on Asian Pears) and even in your warmer climate it doesn't seem too bad, I won't make FB resistance the deciding factor. For instance, I'm planning on adding an Orleans Reinette, though I am putting it on a SW facing stone wall (7-8' tall, 9:30am-dusk sun) which should warm it up early and keep it from being so tardy in bloom.

Chris,
I've had Honeycrisp on M111/M9 here for nearly 15 years - and I have FB every year on pears, quince, mayhaw, and some apples(Lodi, especially, but it is pretty much unfazed by it)in the orchard; can't recall ever seeing any fireblight strikes in the Honeycrisp in all those years.

Bob, I don't think there is enough data for reliable fireblight predictions, the problem is it is geography dependent and pretty random as well. For example the heat at bloom time is a really big factor and it varies a lot from climate to climate. I notice I called Myers Royal Limbertwig somewhat susceptible at the top of this post, but since I wrote the above I decided to blame the couple strikes it got on its very close proximity to the two worst guys I had, Canada Reinette and Berlepsch. Canada is gone and Berlepsch is out next year. It has been getting strikes all summer something horrible.

I don't recall a single strike on my Abbondanza. It was not right by any baddies but it was not too far from the FB-drenched quinces. I looked up that book link and I have many on their least-resistant list that have been perfectly OK for me: Fuji, Gala, Jonathan, Newtown, Cox.

Scott

In SE WI, I have given up on trying to grow Honeygold apple. It was great when I lived in Minnesota, but a big
magnet for fireblight here in my area of SE WI.

I read some of the comments posted that rootstock does not make a big difference on fireblight. I beg to differ.
A friend of mine has a commercial orchard. He planted a certain variety on M7 and then planted the next row of the same variety on M26 as his tree supplier did not have enough on M7 to supply his needs. One spring the row on M26 had severe fireblight while the same variety next to it on M7 was not touched. He swears never to plant on M26
again unless he has no other choice.

This past spring while dealing with FB on just about everything I had planted the previous year I stumbled upon an article online when I googled fire blight resistance. I didn't print it off so I cannot quote from it directly but it stated that the pathogens that form most of the common fruit tree diseases are very similar and that most of them are transmitted by insects, rain, and wind. The big shocker in the article was that it said that FB is laying dormant in certain types of bark on every branch of every tree in the area - that if you are going to spray you need to spray every tree not just your fruit trees. Even though the disease does nothing to other trees, its there, hiding in the bark and all it takes is one windy day for it to blow in and onto your fruit trees. My yard is ringed by forest. Some of the oaks are over 60 feet tall. There is no way I can spray everyone. My plan next spring is to wrap my trees in Remay or spray them with Surround until the daytime temps are above 85.

The Fireblight calculators are fairly easy to use. They will give you an idea when to spray or be watchful.

I am still new to growing apples but it surprises me that fire blight is a problem in a cool zone like Wisconsin. It seems to me that avoiding fb is not only a function of what zone you live in or your tree variety, but also the local environmental conditions of your own orchard plus a little luck thrown in.

Some people like Scott can grow a variety like Jonathan that, from what from what I have read, is susceptible to every disease know to man with no problems. Others grow a variety like Liberty that is resistant to about everything, have a good spray program and still have problems. Growing apples does not appear to be an exact science. Chris.

Here is a link to download one of the programs. There is another one.

Here is a link that might be useful: Fireblight program

Spartan, you are right. Last time I looked into rootstock effects all I could find was information on how rootstock suckers and bacteria heading down to the roots was the main reason for getting a more resistant rootstock. But, I found a recent paper which confirms the rootstock can affect scion vulnerability -- see link below. Note this study is for Gala variety only.

I will have to look at the rootstocks my susceptible trees are on more carefully. I have about half my trees on M9 or M26. This spring my three worst varieties were on MM106 x 2 (Canada Reinette and Berlepsch) and one was on G16 (Orleans Reinette). So none of the problem trees were on M9 or M26. MM106 is not the most resistant stock, but G16 is highly resistant. This is more or less what I have noticed in the past and one reason why I don't pay a lot of attention to rootstock, I don't see a strong correlation in my orchard.

Scott

Here is a link that might be useful: paper

Following up I remember I wrote a list this year estimating sensitivity. I went and added rootstock information, see below. The M9/M26 look a touch worse perhaps, overall its even but the M9/M26 are on average a bit higher up on the list -- only one in the lowest category is on M9/M26.

Scott

Extremely sensitive:
MM106 Canada Reinette (gone)
G16 Orleans Reinette (remove winter 13)
MM106 Red Berlepsch (really bad, need to remove)
M9 Maunerbe
M9 Reinette du Mans
M9 Court Pendu Plat
M7 Esopus Spitzenberg (dead)

Very Sensitive:
G16 Blenheim Orange (late blooms)
(many) Fuero Rous (on late blooms)
M9 Rambour d'Hiver
M9 Tydeman's Late Orange
? Marie Menard
M9 Margil
MM106 Akane
M9 Reinette Armorique
M9 Pigeonnet Rouge

Sensitive:
M7 Myers Royal Limbertwig (but is by baddies)
G16 Claygate Pearmain
G16 Freyburg
G16 Pitmaston Pineapple
M26 Rubinette
B9 Belle Fleur Rouge
M7 Cox's Orange Pippin
G16 Yellow Bellflower
M7 Gold Rush (but could be that it is too close to some baddies)

I never thought root stock susceptibility was about how it affects the scion wood but was the other way around so that a susceptible rootstock can be killed when top infects it. I don't know how I drew this conclusion-but if it's the other way around it's surprising to me that the most vigorous rootstocks aren't the ones most susceptible since fireblight likes vigorous and tender new growth.

Yes, I had the same view as yours before I read the above paper. It has the most vigorous, G30 and M111, as having the least damage and the least vigorous having the most damage.

In fact, it turns out the correlation is perfect: the most vigorous stocks do the best and the least vigorous the worst in their study, and the medium vigor ones are .. in the middle. I wished they had included a highly susceptible vigorous stock for comparison, or a low-vigor resistant one like G16. The technical details are all about gene expression, but that is also closely related to overall vigor. Also they use lab inoculation of trees with the disease which is not directly related with field incidence, so that could be throwing things off as well.

One other thing this study points out is there are many different strains of fireblight and they have different rates of severity based on stock/scion. Its another way it is very hard to make a table of general susceptibility. My pears hardly ever get strikes and I expect it is related to the FB strain(s) that are predominant in my orchard.

Also the differences are not that large in this study, on the more severe strain its something like 20% max difference in how much necrotic tissue there is between different rootstocks. 20% is something you might just barely notice in your orchard when pruning out strikes.

Scott