[NAFEX] Borer revisited

Michael Phillips michael at herbsandapples.com
Sun Nov 27 10:25:51 EST 2005


Hi All,

 

We've been gone for the holiday and I've just noted all the questions about
a "righteous borer tool." Hopefully what follows will answer all the
questions. I am always amazed at what images simple words can conjure up
(and, hopefully, thus learn how to be that much clearer in my writing!).

 

*	My tool of choice to now pry out the borer grub is a 3/8" spade bit,
as sold in the tool section of any hardware store. Irwin and DeWalt are two
drill bit brands.  This bit is used solely by itself - no drill or router is
involved. I am not "drilling" out the grub in any fashion whatsoever. The
spade bit is more akin to a pocket knife, only with it's narrow drill point,
that much more effective in getting down to the bottom of the meandering
grub damage and actually skewering the pest. A stiff wire is useful in this
regard as well.

 

*	What's really, really critical to understand with this insect is how
important it is to successfully get the developing grub in that first fall
season or early the next spring. The eggs are laid in June, July, and
August. One female may oviposit as many as seven eggs at once. Sometimes
another female may come by two months later and add one or two more eggs. A
vigorous growing tree may crush some of these; birds that poke into the bark
at the base of the tree may find a few. All summer long I use the blunt edge
of my hand pruner to smush any fresh egg slits. But come the fall months I
get serious, as in being systematic in going down rows to every tree AND as
is being thorough in opening up the damage.

 

*	People naturally are concerned about damaging the young tree. Truth
is the borer grub has totally destroyed the "cambium connection" wherever it
has been feeding. Thus I always feel free to open up the damaged area and
follow every meandering turn to its end. Again, I want to stress that I am
doing this early along in the damage curve (so to speak) when the 1/8 to 1/2
inch grub has done minimal damage compared to what's to come. The sooner you
get it, the less damage done. Cutting away the dead bark with a pocket knife
or stiff poking tool like a spade bit only reveals the totality of
destruction AND where the healing callus will develop along the edges of the
damage.  The tree itself closes off the damaged area (with or without our
probing) and ideally rebuilds the cambium connection with its growth rings
to come.

 

*	Orange frass coming out of the bark is one visual clue but not the
only one. Blackened bark, sometimes sunken inward, sometimes not, just as
often reveals a problem as the frass. Some borers are small enough to
"contain" their frass early on within the damage area, thus you will see no
frass. These are the ones more easily missed. All egg slits and any dubious
places on the bark at or near the soil line should be poked to see if such
lead onward. Do pull back the soil for an inch or two downward when doing
this check. (My trees have peastone mulch at the base, which helps in this
regard.)

 

*	You absolutely need to see the guts of this creature to know you've
done a righteous job. Some borers go downward for awhile but then go back to
the upper edge of the damage. Some dip around a root and hide on the other
side. Some "merge" into a younger grub's tunnel, leaving you satisfied with
a victory that still leaves the younger grub lingering behind. It really
helps me to see past damage opened-up -- from entry point to the bitter end
- in order to be sure. 

 

*	The adult round-headed apple tree borer is a tan to whitish beetle,
with longitudinal stripes, about an inch long if you don't count the
antennae. Forget that post that said the RHAB is six inches long . . . such
a creature would take us out as well . . . ready guys, here he comes . . .
argghhh!

 

*	Numerous tree species can fall victim to the borer. Wild apples,
hawthorn, serviceberry, and a wetlands maple (don't know the exact species
name) seem to contribute to the extreme pressures at my site. I remove all
unmanaged species on occasion. Migration is limited to a few hundred yards a
year, thus being surrounded by cornfields is probably a big help. If you get
good at "borer duty" you should find a decline in borer pressure over the
years.

 

*	The reason I like the spade bit is that now I have a tool that
combines the attributes of a pocket knife with a stiff wire. What I'm
describing is kind of like dental work: open up the cavity completely, find
the problem, and then let the healing begin. Don't leave gobs of frass in
place to only confuse you on the next search. 

 

*	The idea of an organic syringe is really only a backup to get those
grubs that escaped you in their first year. That's when damage goes deeper
and the surface area loss of cambium often becomes irreversible. Phil Norris
in Maine is the one who suggested a long piano wire for such cases. Now
you're not preventing damage as much as stopping pupation and thus another
round of egg laying when the grub becomes an adult.

 

 

Hope this helps. 

 

Michael Phillips

Lost Nation Orchard

Heartsong Farm Healing Herbs

859 Lost Nation Road

Groveton, NH 03582

603-636-2286

 <http://www.HerbsAndApples.com> www.HerbsAndApples.com 

 

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