Fireblight

[greyphase]

My luck finally ran out and Fireblight has visited one of my orchards. Hardest hit were a Milo Gibson (old Maine apple), Hoover (old Southern apple), Kestrel (Canadian bred apple) and Priscilla. So far just one branch on a Red Limbertwig and a Caney Fork Limbertwig. I've pruned the infected branches off and disposed of them and am keeping a close eye for more of the "shepard hook" branches. My question for you guys that deal with this regularly is how long does Fireblight "season" last? It's been very wet and hot this spring which I suspect is what caused the outbreak.

 

[Native Hunter]

Wow, if you are seeing it on Priscilla it must be bad. It is an above average FB resistant apple tree.

The infection time depends a lot on the weather. I think you could see new infections start up to 3 weeks after petal fall, but would be surprised to see new ones after that time. However, the affected limbs will look bad all season and eventually die down to a point, depending on the resistance of the tree. With a highly resistant tree you won't likely see the infections go past this years growth, but in a serious outbreak, I guess it is possible for it to go further. A tree with little resistance can be completely killed.

My neighbor had a tree last year that was close to the worst tree I had ever seen. He didn't do anything to it. He didn't even cut out the affected limbs. The tree lived, and this year is replacing the dead limbs with new growth. I am surprised at how it has recovered, because I seriously thought it was going to die. And, this year FB is not a problem in this area, so not a hint of it on anything.

Most of my apples are highly resistant, and all of my pears are bulletproof. I cut down one tree a few years ago and watching a couple more. I did have a Brushy Mountain LT that had a moderate infection 3 years ago, but that tree has really recovered well. It is my most loaded tree this year. Sorry to hear about your issue. FB is a menace.

Of course, reducing the size of a tree via dwarfing and semi-dwarfing rootstocks has contributed to the problem. The smaller tree has a harder time dealing with FB than a full sized tree, since a larger percentage of it is infected. Also, there is a tendency to flower at a younger age which subjects it to shoot blight at an earlier age. This is documented fact, but not spoken of much in the apple world for various reasons.

 

[greyphase]

Thanks for the reply, NH. Just checked on my trees and found my Viola Crab with a lot of strikes and a couple good sized limbs in bad shape.

 

[greyphase]

Opps hit the wrong button, wasn't finished. On the Viola Crab many of the strikes looked like this.

And found another Priscilla that I think has fireblight so I pruned it back also.

There are probably 40+ trees in this orchard but most are looking OK.

 

[Prof.Kent]

My luck finally ran out and Fireblight has visited one of my orchards. Hardest hit were a Milo Gibson (old Maine apple), Hoover (old Southern apple), Kestrel (Canadian bred apple) and Priscilla. So far just one branch on a Red Limbertwig and a Caney Fork Limbertwig. I've pruned the infected branches off and disposed of them and am keeping a close eye for more of the "shepard hook" branches. My question for you guys that deal with this regularly is how long does Fireblight "season" last? It's been very wet and hot this spring which I suspect is what caused the outbreak.

I think the "season" lasts as long as temperatures remain above 65F and humidity is high.

 

[chickenlittle]

Did the Priscilla all stop in the green new growth like the one shown?

If you haven't already, look up ugly stub pruning for fireblight. Recommendations on how far back to cut now and follow-up pruning next winter.

 

[Bowsnbucks]

Although it wasn't an apple tree, I had ( just recently cut down ) a Redspire ornamental pear that had gotten FB over several years. - I cut it down due to overly large size, not FB. When it got FB it was in rainy, windy springs, and only affected the new growth. I believe some sources call that "tip blight". I pruned those tips off and went below the affected area, following guidelines. After a few years, I gave up on the pruning and just let nature take it's course. The whole tree was never affected, only the new growth shoots. The FB never hammered the tree completely, and it still had some old FB "shepherd's hooks" on it when I cut it down.

It didn't get FB every year either - only in wet, windy, humid springs. When the blossoms got soaked by several rains and the wind whipped the tree, that's when symptoms appeared. When it was cut down, I looked for FB damage in all the branches as I cut it up. I saw none - no dark stains or any other sign of disease. Only the new growth shoots were hit.

I don't know if that gives any assurance to you guys with FB, but I wouldn't sweat bullets yet - especially if you have DR trees like Priscilla or others. ( I have 2 Priscilla at camp ). Maybe do some judicious pruning & burning of the cut-off stuff, and ride it out.

 

[WTNUT]

Your second photo appear to show where the limb is already turning dark. Having fought a bad case of it, my opinion is you can’t cut too much off of an infected tree. Don’t try to save a few inches of a branch or even the branch. Try to save the tree and the orchard.


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[WTNUT]

Well this thread brought me bad luck, made a check of the orchards and found about 6 trees with minimal amount of FB. It was all minimal shoot blight and I removed it. I hope that is it. Interesting nearly all of it was in an area that would not have likely dried as quickly as the rest of the tree after a rain.


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[BobinCt]

What do you do with a tree that about 80 per of the branches was struck with FB? Tree is prob 4 yr old

 

[chickenlittle]

What do you do with a tree that about 80 per of the branches was struck with FB? Tree is prob 4 yr old

I'd be thinking about what variety will replace it.

 

[Bowsnbucks]

BobinCt - What variety of yours got hit with FB ??

 

[BobinCt]

Not sure. I don’t know if I labeled it. I have like 50 trees but only labeled about 1/3 of them. It was a DR variety tho, but as you prob know, they still get it .

 

[chickenlittle]

There is a group of seedling pears i watch that often get fireblight. FB wasn't bad last year and i noticed one tree held pears through october. I decided to graft that one. They are all getting FB this year. The one i grafted has dozens of small fireblight strikes. Not sure what I'll do with my grafts... maybe give away. For an otherwise healthy large tree, FB is just natural pruning. But i'd rather minimize the risks i bring into my orchard.

 

[WTNUT]

What do you do with a tree that about 80 per of the branches was struck with FB? Tree is prob 4 yr old

I'd be thinking about what variety will replace it.

No sh-t that is good advise. Been there done that. If you only have a few strikes and can eliminate them rather quickly it is a safe gamble. If you are talking 80 percent - wow not good. I will say that I started trimming off the strikes and letting them fall to the ground immediately and leave them there rather than remove them immediately. Couple schools of thought and that seems to work better for me. I go back and get them later to burn.


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[WTNUT]

There is a group of seedling pears i watch that often get fireblight. FB wasn't bad last year and i noticed one tree held pears through october. I decided to graft that one. They are all getting FB this year. The one i grafted has dozens of small fireblight strikes. Not sure what I'll do with my grafts... maybe give away. For an otherwise healthy large tree, FB is just natural pruning. But i'd rather minimize the risks i bring into my orchard.

Hey Chicken LIttle what do you do on a large healthy tree that gets it?


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[chickenlittle]

Hey Chicken LIttle what do you do on a large healthy tree that it?

Not much you can do if you can't prune out all the FB strikes. Decide if that tree is worth keeping or not. If it tolerates FB, it will survive but it will be a carrier/host of the fireblight bacteria that can infect other trees. If all your varieties are tolerant, no real worries. Those that are not tolerant will go away.

At some point, wildlife trees have to survive on their own. Try to pick good ones on good rootstocks. Baby for a while and let then let nature decide.

 

[Barndog56]

I'm told a foliar fertilizer called SeaCrop has been shown to be effective against fireblight in apples. It is a product by the folks at Advancing Eco Agriculture. I'm using products from them in an effort to prevent Apple Scab, which seems to be working well so far.

www.advancingecoag.com

 

[greyphase]

I just realized I misidentified one of my trees damaged by fire blight. It was not a Priscilla, it was a Pristine. I guess I didn't cut enough off the first time I pruned and now it's toast.

Also cut the central leader off of a Kestrel because the wood looked suspicious.

 

[aerospacefarmer]

Damn that’s ugly