One year Lee’s orchard got hit really hard with fireblight. With so many varieties and the right conditions it can run amok and overwhelm even the most resistant ones.
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Some varieties have to be typhoid Marys. I know that here, quince brings FB to orchards that likely would otherwise not get it on apples and pears.
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I’m quite sure too much vigor (too much nitrogen in most cases) is responsible for a lot of the fireblight in apple trees. I suspect stress in general may also mean less resistance in a plant.
Alan made a good point that some light damage on tips of limbs is not same as having a tree killed. (I’ve never had a large tree killed…but younger ones I have.)
The vigorous seem to be most at risk of getting a strike (but also seem to recover).
Stayman/winesaps get fireblight pretty easily here…but only current year shoots seem to get killed…(unsprayed trees).
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Compact spacing with low to the ground trees are tailor made for fireblight.
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Fireblight on apple is not usually that big a deal around here, but this year I saw a fair amount of it in one particular area. This was on very old trees that had been recently and heavily pruned. It looked like the damage was limited to certain branches on the trees, but I couldn’t tell anything more than that. We’ll see how they do this year.
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Here fireblight is present. A local orchard lost their crops on Northern Spy one year. I haven’t really seen fireblight on my apple trees with the exception of one tree that suddenly died but I suspect that was probably a root issue of some type but it is hard to be sure.
On the other hand I have a large Cleveland pear ornamental tree right next to the orchard. This year it was covered with fireblight strikes but nothing showed up on the apple trees. I did pick apple trees and rootstocks that had resistance to fireblight and that probably helped. Also my trees are almost all on dwarf rootstocks… I don’t have large trees that tend fare well with fireblight strikes.
If you have fireblight in your area I think you would want to pick trees and rootstocks that have some resistance to fireblight. Also resistance does not mean immunity. A resistant tree can die from fireblight if the disease pressure is intense, or it is weakened by poor health. Here are some charts that list fireblight resistance.
However, I will caution you sources don’t always agree on the level of resistance. I think this is due to various factors, field studies being done in different areas of the country, different fireblight strains, etc. But the charts are still pretty useful.
Disease Susceptibility Ranking of Apples – Database of Apple Diseases
https://www.extension.purdue.edu/extmedia/BP/BP-132-W.pdf
Table of Apple Cultivar Fire Blight Susceptibility – Apples
https://treefruit.wsu.edu/article/fire-blight-susceptibility-of-apple-cultivars/
https://blogs.cornell.edu/khanlab/extension/fire-blight-susceptibility-of-common-apple-cultivars/
I think Alan already posted the last one from Cornell but I went ahead and included it as it was on my list. Plus I think the WSU link above is a really good study with lots of detail.
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I think I"ll order one of the ‘Mutus’ apples on that “Table of…” link.
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2024 Spray Bulletin (VA, WVA, MD) out. Fireblight instructions have changed a bit - more emphasis on application of heavy concentration of copper during dormant season. I think this will help. Key is to apply with dormant oil at least twice, gets the scale and reduces FB issues in my experience. Even then you have to watch for it. Since we should be pruning soon, if you see damage remove it.
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Paducah is the only variety that is FB free go me here in middle TN…out of 5 or 6 varieties…all trees less than 5 years old
Ditto Paducah blight free ten years here in Maryland.
Bet I could plant a Paducah and in 3 or 4 years when blooming good… it would have fire blight all over it. My luck with apples.
My (very resistent to FB) Novamac is not dead yet… but it has been hacked to pieces, looks awefull… and about every two weeks since the initial load of FB this spring… i find more that needs to be removed.
I heard Chieftain is Fireblight resistant. Fire blight ran through my P2 grafts and knocked them down to 18 left. I have 20 left on M111. A lousy 4 on G.214.
Saved some living scions and will try to chip bud to try to recover from the onslaught. Still about 30 late grafts I’m waiting on.
commercial varieties that have good to excellent FB resistance are Winesap, Golden Delicious, Red Delicious and Honey Crisp. My 39th parallel tree is very resistant and clearly had Red D genetics (might be Starking). Ozark Gold ( Golden D , Red D cross ) is very promising . My advice is to look for varieties bred from resistant parents. The problematic varieties usually have a highly susceptible ancestor like Jonathan, Cox or spitzenberg
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In 2002… I planted a red delicious here with my early mcintosh…
It started blooming about 3 years later… got a load of FB and died late spring the next year.
I tried a Fuji next… same thing happened…
In 2020… tried some later blooming supposidly disease resistent apples… Akane, Hudson Golden Gem, Gold Rush…
Once they all started blooming good… loads of FB… goners now.
2022 bought the Novamac on b9… it bloomed heavily this spring… got 30-40 hits of FB… I have removed the large majority of fruit spurs at this point, the last foot or two of most scaffold branches, almost all of the central leader… and many other vegetative shoots as the tips die, wither, turn brown/black.
I will be suprised if it lives another year.
Just checked my very resistent to FB Novamac again… and again more shoots shrivel turn brown.
It has 4 scaffolds (espellar trained).
I have removed all of the two bottom scaffold branches now… except about a foot of the bottom right one.
The wood i have been removing lately has apples on it… many have started to shrivel up already.
The top two scaffold branches are looking better. Have not had to remove any wood from them in the past few weeks.
It is very clear a new strain of fireblight is making the rounds. All the G.214 that died. Rouville dead.
This is much like the many 1980’s scab resistant apples that did great. But now are succumbing to new races of scab.
Any kind of pruning or stimulation of new shoot development makes the tree that much more vulnerable to FB, maybe going forward only grow the most resistant apples with absolute minimal pruning and in very poor soil
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http://www.chathamapples.com/ApplesNY/SEApples.html
Apples that can do well in the SouthEast
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Sorry to hear that. I’m seeing strike on supposedly highly resistant (PRI) apples. I will be doing a good amount of chainsaw pruning soon and really reevaluating the future of the orchards. I hate that you never know how something will fair until it’s in production.
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