What to do with apple tree prone to fireblight?

General Fruit Growing
#1

One of my apples, a “Strawberry Parfait”, has been the worst tree in my apple orchard for both fireblight and cedar apple rust. The tree is almost 4 years old, and about 3 inches diameter at the trunk base. It has been my best growing tree, but also seems to be the most disease prone.

Last year, I saw a few light strikes of fireblight that I promptly cut out. This year has been much, much worse. So far, I have had to cut out the top of the tree, plus a lot of side branches. There are still sunken spots in the bark on several branches, with some close to the main trunk. If I remove all of those, there will be nothing left but a stump.

So, my question is what to do with this tree? I don’t want it to end up being a disease source for the rest of the orchard, which has some susceptible varieties in it, that so far have been spared.

I have thought of the following:

  1. Leave it alone and see if it can just deal with the fireblight on it’s own.
  2. Pull the whole tree up and start over with a different variety.
  3. Cut the trunk off about 2 or 3 feet off the ground (removing all sunken areas in the process) and try to topwork in a different variety to the trunk.
  4. Cut the tree off below all sunken areas and let it regrow from the stump that is left.

I am tempted to try option 3 first, and if that fails, try option 4, or 2. I’m not sure how successful I will be with topworking it, as I have never tried to do it before. I have an Ashmead’s Kernel that I will probably try to use, as the Kernel I currently have is not doing well…maybe do to location. My fear is that having the Strawberry Parfait as an intermediate stem would impart some of the fireblight susceptibility to the Ashmead’s Kernel.

Thoughts?

#2

Knowing your location and rootstock will help.

Here’s the way I prune out blight, called “The Ugly Stub” method from U of Md Prof. Steiner that I learned about here on Growing Fruit. Any other method I try has spread the disease, not eliminate it. I lost almost an entire orchard by following conventional blight pruning advice.

The gist of the Prof. Steiner Ugly Stub method for me is: do not do normal summer pruning and blight pruning at the same time. Do normal summer pruning only when temperature is over 90 degrees (blight inactive). Prune out blight strikes when you see them, cutting back into at least two year old wood AND leaving an “ugly stub” of 4 to 6 inches that you remove with a flush cut next winter when it’s impossible to spread blight because it’s inactive at low temps. That’s my best understanding.

Combine this with annual winter close examination of every tree surface for over-wintering FB cankers that you carve out or disinfect. Google photos of blight canker.

#3

Central Virginia, on the edge of zone 6b and 7a. I sit high on a ridge and have had a lot of trouble with freeze damage, Mostly on blooms with the apples. Non-apples have had much bigger issues.

Root stock is MM111

#4

Winesap and Braeburn are supposed to be among the bad ones for fireblight.
My 30+ year old trees have only been sprayed dormant oil, and a couple years malathion.
May have “amputated” a few limb tips, but has not threatened the life of the trees.

#5

I have a Winesap in the orchard. It showed one bent limb from fire blight this year, and that is it.

#6

I did not know about the ugly stub method. I will have to start doing that. I have been cutting the affected limbs off flush at the branch junction. Perhaps I have been making things worse.

2 Likes