Re: What makes holes in walnut trees?

bp@www.zefox.net wrote in rec.gardens:

>
http://www.zefox.net/~bp/walnut/

Many different beetle grubs attack barks and cambium. Some do not
even threaten the tree seriously, but most do.

The holes look the same to me, no matter which species cause them. I
cannot find a beetle that would have a predilection for Nut Walnuts
other than a bork beetle “Pytyophthorus Juglandis”.

You will have to find the beetle, to know, I am afraid.

The risk with the Pytyophthorus Juglandis is that it transports a
fungus which destroys the tree. But there is nothing on your photos
that could identify the grub reliably.

Anyway. No chemical product exists which could act against an
ongoing infestation. Usually you have to get rid of the beetle.

At least, the grubs that destroy fruit trees, here in France, drills
differently and you can even see the path that the animal takes
under the bark… oftentimes terminating in a second, bigger hole,
where the woodpecker intervened. We otherwise kill the beast by
pushing a small twig into the canal. The grub is usually at the end.
You see that you have killed it, when the twig is … humid at the
tip.

You could try that at the hole on your second picture. On the first,
the grub appears to have failed to enter the bark.

I am curious to read other opinions.

Cheerio
--
"I'd trade all my tomorrows for a single yesterday."
(Janis Joplin/Kris Kristofferson – Me And Bobby McGee)