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Borer recovery

Posted by John Stoltenborg 
Borer recovery
June 30, 2015 05:54AM
I have a fine looking 5 year old apple on an m111 rootstock, which I've grown fond of.

Yesterday to my dismay I found a pencil sized exit hole several inches above the ground and have begun gaining experience as a pest detective. I've found a lot of documents from extensions and I've come away with the notion that an exit hole usually means it's too late and that it's probably an apple borer. I put a wire in the tunnel and I can get about 2 inches in before failing to be able to continue.

At this point is my only option to wait and see what the damage is?

Ironically besides this it's the healthiest looking tree I have growing and is putting on some nice first fruits this year (Initial apple).


Edited 2 time(s). Last edit at 06/30/2015 03:37PM by John Stoltenborg.
Re: Flatheaded Appletree Borer
June 30, 2015 03:36PM
This is a small home orchard in Scarborough, Maine - Zone 6A.
Re: Borer recovery
June 30, 2015 04:04PM
Read the Question of the Month feature in the May edition of the newsletter. Timely, eh? That "hole higher up" is where a new adult beetle recently exited this tree, and she's out there now laying eggs in other trees. This is definitely Round-Headed Appletree Borer [RHAB] given that you are in Maine. The bigger concern as regards the future of this tree is the damage done below over the past two growing seasons. The effect is not unlike a vole girdling cambium above ground. A weakened tree can recover but you sure as heck need to be more vigilant about future infestation. Staking the tree may help until it reestablishes roots (if it does) above the chew zone. The recommendation in the newsletter to use neem butter and a comfrey poultice refers to wrapping early damage down below.

I just removed a five-year-old tree myself, being a Chisel Jersey cider apple whose leaves were looking mighty sad. One borer given one year - I missed it last fall - had wound it's way around 85% of the girth of the tree just below the soil line since the egg hatched the previous summer. The grub itself was just over a half-inch long and would no doubt have made it to the finish line, all the way around, given it's lateral trajectory. (And yes, that borer grub met a brutal end!) It's taken me a long time to know when to call a spade a spade as regards a tree not worth saving.

Hopefully someone else can offer a more upbeat perspective, John!

Lost Nation Orchard
Zone 4b in New Hampshire
Re: Borer recovery
June 30, 2015 07:44PM
Hi John,

Borer hell . . . I know it well. *Pouring a cold pint of cider and sliding it over to John*

I have also had young trees girdled by borers to the tune of +/- 80% of the circumference on three trees that come to mind. A Newtown Pippin, a Smokehouse and a Snow (Fameuse). Of those three, the healing that came after the surgical borer removals and explorations, freshly painting those trunks and some added TLC throughout that remaining season (this was in 2011, by the way) resulted in a full recovery for the Newtown and the Smokehouse (both of which are now producing annual crops). The only tree I lost was the Snow and that was due to a mistake I made on that particular tree: it was in a more wind exposed area and that winter we had a storm that came with 70+mph winds and it was snapped clean off where the borers had done their damage. The mistake I made was in not staking that tree right then and there when the damage was found.

With the damage caused by the borers to these trees, I opted to not only dig out the borers, but to also use a very sharp razor blade and trim out all the dead tissue until I got up against 'green' living cambium. Then I let the area air dry for a day and then painted it the following day. I wish I had photos to share of the devastation to the Newtown alone.

To give you an idea of the extent of the damage, the Newtown Pippin tree I am referring to here had eleven (11) borers in it!!! My current record and one I hope to never see challenged, in my orcharding lifetime.

It was shocking, and my borer nightmare in 2011 was one of the most painful experiences I have had in my orchard to date, but I have learned 1st hand that apple trees are incredibly resilient and can come back strongly from this kind of damage. You will need to assess that though, as each tree is unique. You said this tree is one of your best . . . and I would add to that that this tree is a member of your family, and well worth doing all you can to help it make a full recovery.

Cheers to your success!

Gopher Hill Apples
Zone 8 in California
Re: Borer recovery
July 12, 2015 03:57AM
Hello Michael and Paul,

Thanks to you each for taking the time to share your experiences. Lessons being learned.

Paul, I came back to this thread while having some cider from a friend here in Maine (Portersfield) so your virtual pint was timely.

I am going to take some action to save this tree, and will take some photos of the process to contribute here. Thanks again. Glad to be a part of a group of this quality.


Edit: Here is a photo I took of the exit hole - [goo.gl]

Edited 1 time(s). Last edit at 07/12/2015 04:11AM by John Stoltenborg.
Re: Borer recovery
March 06, 2016 02:52AM
I would like to resuscitate this topic, (rather than create a new one). I was innocent of the peril of RHAB in the past, until my trees started shedding their bark around their bases. (This is what happens if the borer eats all the cambium; the overlying bark eventually sloughs off.) Once I saw the light, I set about trying to save my poor trees by inarch grafting root sprouts, (when the tree is no longer drawing the sap, the roots respond by throwing up multiple sprouts). This actually seems to have been quite successful in some instances. But I still have the problem of eliminating the borers in other trees. I tried the poking-wire-into-the-hole process - a complete bust. I balked at destroying any more of the bark by hacking at it in an attempt to follow the burrows. And I hit on the idea of injecting insecticides into the holes with a syringe and needle - a couple of cc in each tree, highly focused, total quantity of poison added to the environment minimal, benefits surely exceeding harms.... And what is the alternative? If I don't go for the biggest guns I can muster, I won't have any trees left. (Oh, the rationalisations one has to create to assuage a guilty conscience.)

Now I would like to confess my sins and seek absolution. Is there, in fact, no alternative? Does smearing raw neem oil on the trunks really kill the critters? (Painting the trunks with clay in latex paint does make it easier to find the holes, but it doesn't have the slightest impact on the females laying their eggs in yet more trees). This isn't a matter of getting an increased crop of unblemished apples - it is literally a matter of life or death. Unless eliminated, (not just controlled or reduced), these critters will gradually wipe out my entire orchard. I can't afford to experiment with solutions which may or may not work . Does anyone have clear cut evidence of successful methods? And, if others have gone the route I used - injecting poisons into the holes - what agents did you use, and did they work? (Anybody got any experience with using moth crystals dissolved in vegetable oil? This has been proposed, and sounds plausible, (and a lot less toxic), but, as I say, I can't afford at this point to experiment. I need to know that it works.)

Addendum: I just discovered that I raised this identical discussion a few years ago. (That's a major problem with growing old - you start repeating yourself). Anybody have anything new to contribute based on their experiences in the meantime?

Broomholm Orchard
Zone 5b in Nova Scotia

Edited 1 time(s). Last edit at 03/06/2016 03:02AM by David Maxwell.
Re: Borer recovery
March 06, 2016 04:05PM
I've never dealt with RHAB before, no matter where I've grown apples, so I am going out on a limb here (haha get it?). I have read articles of where growers dealing with Dogwood borer, peachtree borer, and other larval borers (Yes, RHAB is not larval, but a grub) have applied a poultice of parasitic nematodes to the wound. The poultice keeps the nematodes moist and viable as they "worm" their way to the prey. There are specific species and many ways to do this; I can expand if there is interest. But just to be clear, I don't know of anyone that has tried this, but it may of interest. As well, Japanese beetles (more closely related) can be somewhat controlled with a long-term focus of using Bacillus papillae to inoculate the soil where the grubs are feeding (mid-summer). Perhaps the same approach could be used by injecting into the wound and, again, resealing. Finally, Beauvaria bassiana (Mycotrol) is a commercial prep of a naturally occurring organism that has some effect on hard-shelled beetles. RHAB is not a hardshelled beetle, but nonetheless this could be yet another option to poisons and poking around with wire hangers. I haven't tried any of these approaches, nor have I read of anyone trying. Cornell's IPM fact sheet suggests that keeping trees in very healthy state is a key strategy, so not planting near abandoned orchards (where there could be an endemic population) or allowing your own trees to become overly stressed, could reduce future infestations. 1+1+1=4?

Mike Biltonen, Know Your Roots
Zone 5b in New York
Re: Borer recovery
March 07, 2016 10:12PM
I did use the injection method for a while - rotenone is the stuff I injected. It did work, but now I prefer to open-up and actually kill the beast - this way, I have no doubt the beast is gone.
My tools are copper wire (I use the ground wire from #14 house electrical wire) and a good knife.
Depending on the situation, I usually clean-up the area of the hole with the knife and find the tunnel. Then I go with the wire until I hear the characteristic squish. Sometimes I need to open more to make sure.
Once the thing is dead, even if a lot of the bark is gone, a young and vigorous tree will heal quickly. Once I was almost certain the tree would die as it was almost completely circled. But there was a thin peace that joined the root to the trunk and by the end of the season, it had well recovered.

Jolicoeur Orchard
Zone 4 in Quebec
Author, The New Cider Maker's Handbook
Re: Borer recovery
June 01, 2017 02:58AM
An update - the tree has faired well. Lots of fruit set this year, and the hole seems to be healing up. No borer signs on this or any other tree since.

Here's a photo of the tree with one of my boys for scale: [goo.gl]
Re: Borer recovery
July 10, 2017 10:01PM
Hi John,

That is great news on your favorite tree being given a clean bill of health. Cheers to that success! Arent Apple trees amazing?!

I would recommend that you consider painting all of your young tree trunks up to their fist lateral branches, minimum, with a 50/50 (water/cheap white interior grade non-fungicide containing base paint) and help those trunks stay protected through their teenage years still ahead. . . Plus if they are painted, it is a heck of a lot easier to see the borer frass against that white back ground too

May the borers continue to find their meals elsewhere

Good luck!

Gopher Hill Apples
Zone 8 in California
Re: Borer recovery
February 25, 2020 05:44AM
Checking in at the end of dormancy 2020 - the tree is very doing well.

Arent Apple trees amazing?!

Hi Paul - indeed. I'm glad to be on the other side of this coin and I am thankful for your and Michael's advice.


Edited 2 time(s). Last edit at 02/25/2020 05:46AM by John Stoltenborg.
Re: Borer recovery
February 17, 2021 06:46AM
Just thought I'd throw in my favorite borer tool. I use a piece of heavy duty plastic "string" from a string trimmer/weed whacker. Flexible but not too flexible, it can really ferret out a long borer tunnel. Plus, it's easy to do Michael's suggestion and cut in barbs at the tip to draw the beast back out to make sure it's really, truly dead.
Boy, borers are the worst. Much rather lose a tree to a vole.

Nat Bouman
Growing cider varieties in Zone 5b
On B.118 at 18X24
Susquehanna County, Pennsylvania
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