Is fireblight treatable? (once heavily established)

luke capa

Member
We had a some hail last spring and pretty much every crabapple and apple in the area has fireblight. Many are completely covered to the point where sanitation pruning is almost not an option because the entire canopy has fireblight. Is there anything that can be done I have looked into copper sprays and ArborOTC. Should we spend the time to prune out all of the infected branches? (probably not economically feasible due to the time it would take) Will sprays or injections actually prevent the spread or are the trees goners?
 

GregManning

Super Moderator
Staff member
I am not an expert ................
35+ years ago I had ~35 producing fruit trees (apple, pear, plum, etc).
They got fire-blight.
At that time I was told to prune & spray with streptomycin; which I did for several years.

The trees were doomed.
Pruning without some very effective disinfection, just spread the problem.

There have been a couple threads here on TB about disinfection.
I still do not know how to do it properly, without EXTRAORDINARY time, effort & equipment.
 

luke capa

Member
Yeah generally we remove trees when fireblight gets real bad im just wondering if anyone has every "cured" a tree with sprays/injections. The hail storm opened up many wounds on the new growth of the trees allowing fireblight to enter. Generally it is spread by bees going to sweet ooze created by the bacterial and they spread it into new flowers but with many open wounds the trees got completely covered.
 

Tom Dunlap

Here from the beginning
When a client had a tree that served a purpose...screening, shade, flower color..or other criteria I developed a procedure I called 'amputation to death'. The client was never given any hope of curing the disease. We'd cut off the worst limbs and leave the rest.

The client was told to call when the tree looked bad enough to do another amputation.

What I found was that many of the trees didn't need another amputation for 3-5 years. I figured that was about right. Some of the trees were visible from the street so I'd get to keep an eye on them over the years.

The client was never given any expectation of a nice 'healed' tree. Only occasionally did I ever come back a second time for a removal.
 

luke capa

Member
Yeah Ive been telling people to wait and see. Definitely don't want to remove trees unless its needed but I would like to help the trees in any way possible. It seems every apple tree in Lafayette has fireblight on every branch but at least the crabapples seem to be slightly more resistant.
 

Serf Life

Well-Known Member
WSU extension Has good info and super in depth assesment survey. Your local coop extension is a stellar resource and their fruit folks get to see mult properties and what works etc. in your specific area. Studied fireblight infections on pear back in the day and the disease is very unpredictable and influenced by so many factors out of our control. One orchard can be crooked out and one next to it fine based on microclimate or variety or maybe biodynamic snake magic. As with many orchard issues we are not always well suited to help as we can't be monitoring every day around bloom time...
 

luke capa

Member
Thanks ill read that. I went through everything I could find from CSU but they didn't have much to say other than approved treatments. I just know that I have never seen a tree come back after infection of entire canopy but I also know my old company never really did much other than sanitation pruning.
 

JD3000

Most well-known member
Preventative antimicrobial applications can be wonderfully effective but not terribly realistic if you're doing residential setting. Folks that run orchards use programs that measure optimal weather conditions at and around bloom to time their applications.
 

Amber Jones

New Member
If the tree is mature enough it might fight it back, I believe it's bacterial not fungal so it does matter what you put on it it needs to grow up past it but not grow so much the new growth gets it again, proper cuts while cleaning your tools allot otherwise your spreading the blight.
 

ATH

Well-Known Member
We had it pretty bad throughout the area on a lot of Callery pear a few years ago - something in the weather triggered it. Have seen spots here and there since, but not so wide spread. Every twig was infected on many trees. Pruning would not have been economical, practical, and I'm not sure there would have been any tree left if we went by the "prune behind visible infection 6-8 inches". Often that would have meant taking off structure limbs.

So pruning wasn't an option. Again, this is where orchards are different...they often catch the infection early and prune it out immediately. That is growing season pruning when sanitation is important. I'm not so convinced sanitation makes a difference for dormant season pruning (thinking Dec/Jan/Feb - before sap starts flowing).

I talked to a lot of people looking for options. Tried a few with the promise to clients "this will NOT eliminate fireblight from your tree...we are trying to limit the impact and prevent further spread."

My first assumption is that a healthy tree is more able to deal with a pest that an unhealthy one. Is there anything else going on that we can do to help. Often that is root collar excavations for trees that had mounds around them. Sometimes it is mulch and a little extra water (soaker, not sprinkler).

Avoid high nitrogen fertilizers. The fast growing young suckers are more susceptible to new infection.

Here is where it gets controversial...
*Cambistat reallocates tree resources from shoot elongation to root growth and defense mechanisms. It is also suppresses those quick growing shoots. Again...not a cure, but helps the tree fight.
*Reliant bark spray (not just the trunk - whole canopy) has been reported to work. Trunk spray will help with suppression, but on bad tree, I'd do the whole tree.
*There is another "recipe" that I got from PSP Enterprises that is Reliant plus an anti-bacterial called Prontec. Trees are not on the label...but he says it works well.

*A well timed streptomycin should also help prevent NEW infection - but won't cure old.

Results? The trees i have been caring for look good (mostly Cambistat and RCX). But then again, pear trees are so resilient, trees infected that year that I haven't treated are still around... jury is still out to me.

PS: forgot to add: copper-based fungicides should also prevent further infection.
 
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Chaplain242

Well-Known Member
Just a question, have you tried treating fungal infections with clove leaf oil? I managed to treat a largish Ganoderma infection with clove leaf oil solution with no reinfection.
 

JD3000

Most well-known member
I'm skeptical about knocking of a fruiting body and spraying any fungicide to the area. Tip of the iceberg as they say.

All that said, I've done the same with a tank spray rate of Agrifos...
 

Chaplain242

Well-Known Member
As a spray or soil drench? Any study to reference? @Chaplain242
No reference - traditional use is a mould killer.

I cut a lower branch with a nearly 2 foot long bundle of ganodermas hanging off it off the trunk, and it had spread right down into the lower trunk and had white mycelium spreading all through the bark up into the tree. Sprayed it with 3% solution, and drilled a hole in the trunk at the uppermost part of the infection, and filled hole with solution so would slowly absorb or at least migrate over time over area. As a safety, sprayed it again lightly in a week over main infected area of trunk. Few weeks later came to look at it again and all the infected area had crumbled and no mycelium visible anywhere... I thinned crown to reduce drain on tree, and even now two years later still no sign of reinfection.
 
We had a some hail last spring and pretty much every crabapple and apple in the area has fireblight. Many are completely covered to the point where sanitation pruning is almost not an option because the entire canopy has fireblight. Is there anything that can be done I have looked into copper sprays and ArborOTC. Should we spend the time to prune out all of the infected branches? (probably not economically feasible due to the time it would take) Will sprays or injections actually prevent the spread or are the trees goners?
Here's a PDF from the University of CA on management practices for the infection.

When a tree is infected heavily the tree will not fair well.
 

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Amber Jones

New Member
No reference - traditional use is a mould killer.

I cut a lower branch with a nearly 2 foot long bundle of ganodermas hanging off it off the trunk, and it had spread right down into the lower trunk and had white mycelium spreading all through the bark up into the tree. Sprayed it with 3% solution, and drilled a hole in the trunk at the uppermost part of the infection, and filled hole with solution so would slowly absorb or at least migrate over time over area. As a safety, sprayed it again lightly in a week over main infected area of trunk. Few weeks later came to look at it again and all the infected area had crumbled and no mycelium visible anywhere... I thinned crown to reduce drain on tree, and even now two years later still no sign of reinfection.
Wow good work I knew it attacked the new growth, that's a good idea to cut into it's supply to the bacterial infection it has to grow past it but not compartmentalize it nice job
 

Chaplain242

Well-Known Member
Wow good work I knew it attacked the new growth, that's a good idea to cut into it's supply to the bacterial infection it has to grow past it but not compartmentalize it nice job
Yes was surprised how well it worked. Fungal infection. Still has a hole in the trunk where the infected tissue crumbled away, but still hasn’t reinfected with any fungus and now nearly 2.5 years since treated.
 

ghostice

Well-Known Member
I've used Bordeaux mix (copper) on crabs (even though its recommended for fungal stuff and fireblight is baterial) and some pruning - for what it costs might be worth a try. Supposed to be started before bud break then another spray or two every couple of weeks or so. Some of the crabs have had a tough time, made worse by squirrels chewing the bark off some of the branches. A lot of our trees bark damage was due to bad hail. Others we just removed - older trees on their last legs before infection. And I agree with not going wild on the watering, esp. if you're getting the trunk wet. We sterilized the pruning tools between cuts and take great care where we made the cuts. Some made it, older trees though not so much.
 
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