The dreaded F word (Fireblight) is showing up in our orchards


#222

Thanks Barry. Is the discoloration black? I’m hoping six year old wood has extreme resistance to blight. Going on the theory that younger wood is more susceptible to blight.

How old was the tree or trees you lost?


#223

Mostly brown. My trees were around 3 yrs old. I let a lot of flowers bloom on 1 yr old wood with no antibiotic spray, and fb tore through that young wood. Hopefully your older tree holds up better. I hope you can do a modest cutback instead hacking it off low.


#224

Does this look like fireblight in the heartwood and sapwood? I sawed below it where wood is clear, no sign of discoloration. Will bark graft and find out soon enough if I cut low enough. Caney Fork Limbertwig and Kentucky Limbertwig (shown in photo) have turned out to be blight magnets here with blah/meh taste, so they are now officially gone. Ditto Virginia Beauty.

Note to Limbertwig collectors: All three Royals show excellent blight resistance here in 7B: Royal LT; Red Royal LT and Myers Royal LT. Black LT gets its share of bight but so far is manageable. Too early to say for Swiss LT and Victoria LT, but so far so good. Guy Ames in Arkansas says Royal LT resists all major diseases. I think it was Calhoun who raved about Red Royal LT as one of his favorite eating apples.

IMG_0119


#225

We have been fighting FB for a long time. Don’t believe it can be controlled in my area when it rains a lot during bloom. Young dwarf trees are the most susceptible. The worst place for a FB infection is on the leader of a young dwarf tree.

We had very little FB for the first 3 years but we got clobbered in year 4. We removed the worst trees. Cut the leaders on many more which survived but were stunted. Cut out about and destroyed about 2 pickup trucks of infected material on about 400 trees.

Now in year 8, we decided to remove most trees with cankers on the leaders. Some trees were in slight decline but producing some fruit, but lots were productive and looked normal except for 1 major canker on the leader. Some of the cankers may have been some form of Bot rot.

Just 1 FB canker contains enough bacteria to infect an entire acre of apples and hopefully removing most of the infected trees will reduce the amount of available FB bacteria and will help us in the future.

This year we plan to spray copper and oil a little late and not worry about the russet then spray strep based on the cougar blight model through NEWA. This model uses weather info from my local airport to make predictions about a coming FB infection. I try to spray strep ahead of the infection, but when it rains everyday its impossible to spray in time to kill the FB bacteria. Probably use some Apogee for shoot blight on some varieties, but not Stayman where it promotes splits. It may promote splits on Goldrush too, so no Apogee on Goldrush this year.

The label for Lime Sulfur has been extended to some mid Atlantic states for bloom thinning and perhaps FB control. Its often used in Washington for both purposes.


#226

The inside of a tree is not alive. The outside layer of the tree aka cambium layer is the living part of the tree. Fireblight only attacks living tissue.


#227

Thanks Clark. Any idea what this discoloration is in the photo? It peters out the farther away I cut from blight cankers.


#228

I’m not sure what’s causing it but it could be death of cambium that is allowing water to get to internal wood.


#229

That’s how my fb trees looked inside when I cut them down. My $ is on that being fb but I’m no expert.


#230

Thanks for your ideas guys. I’m going to cut below it just to be on the safe side. It seems to peter out pretty fast as I head South down the leader.

I should never prune when I’m tired or in a hurry. Today I accidentally cut off a three year grafted branch of Royal Limbertwig that was all spurred up. Damn. Really want to taste it. So I cut up scions and will graft them back on!! A lesson in patience, Time and care, etc.


#231

This is a 10 year old Bartlett pear that became infected with fireblight last spring. We are hoping to graft some resistant scion to use the established trunk, but when we were out today taking off limbs I got to inspecting the trunk. Does it look like the FB got to it too?


#232

Have you considered using more vigorous rootstocks. I’ve never lost an apple tree to FB and most of my trees are on 7 or 11. They get plenty of strikes at certain sites but always recover. The big old seedling rooted trees seem almost immune to having strikes lead to actual big wood.


#233

http://treefruit.wsu.edu/crop-protection/disease-management/fire-blight/
In this article one thing that is mentioned is using a blowtorch on cankers in the winter. Has anyone heard of/tried this before?


#234

Yes. Wish I had more vigorous rootstocks but its too late to start over. I never lost a tree from a big box store on what was probably mm111


#235

Question: My friend’s Myers Royal Limbertwig (that I take care of) kept the top leaf over winter on many vertical shoots. Is this always a sign of fire blight or can there be other causes of over-wintering leaves on top of apple shoots? Zone 7B Maryland.

If not blight I could save a lot of pruning.

Thanks for ideas.


#236

Do the leaves look normal ( for the weather) or are they on shoots that look like burnt shepherd’s canes ( curved downwards)?


#237

Normal leaves, no blackening or shepherd’s crook. I’ve read many places over the years that over-wintering leaves signal fire blight. Same for over-wintering leaf stems without leaves.


#238

I have not heard that actually. I know we had a really crazy fall/winter/summer/fall winter ( I am talking weather wise all in Nov through January) and a lot of my trees still had leaves on them because we really did not have a proper fall- going through the cooler days before turning really winter cold. I figured it was just because of that. If you are right Just about half my trees will have fire blight next year. Keep me informed of what transpires with that one tree you mentioned, if you do not mind. I am curious now about that. I did have a little branch blight last summer. It was my fault though. I fertilized my trees right during a long drought. I did not know it was going to be that long of a period without rain. I cut the blight out but I lost one tree from trunk oozing. I hope that is not a sign of more FB with the leaves being left on the trees.


#239

Fireblight experts: Are these over-wintering apple leaves at the tips of vertical branches evidence of fire blight? Somewhere I got that idea. It would save me a lot of pruning if they are not blight as there are lots of them. They are not blackened. IMG_0121


#240

I sure hope not Steve, all of my trees look similar.


#241

Shoots of mine that grow into the fall hold their leaves like that. If the twigs look ok inside I’d vote for no FB