Bonsai Study Group Forum

Species Specific => North American Juniper Bonsai Discussion => Topic started by: PaulH on June 01, 2010, 01:12 PM

Title: Borers in my Sierra juniper!
Post by: PaulH on June 01, 2010, 01:12 PM
I've got a big Sierra juniper I collected in 2008. Last week I was working on it reducing some of the jin and out popped an ugly borer grub. I don't see holes anywhere near the live wood but I need to evict those buggers. Anyone have experience with this that can offer a solution?

Title: Re: Borers in my Sierra juniper!
Post by: bwaynef on June 01, 2010, 02:07 PM
So, you've determined that the borer(s?) are only targeting the dead wood?  See my earlier thread on insecticides to let you know my experience here (reactionary w/ insecticidal soap unless otherwise warranted).

If that's the case, I'd reason that systemic insecticides will do nothing for you, so I'd look for mechanical (poke 'em) or topical solutions.  I'd tend to think it would be wise to treat the living parts of the tree in addition to the dead, but I'm not sure it'd be necessary.

Have you identified what kind of borer it is (if that has any bearing on the efficiency of different chemicals)?
Title: Re: Borers in my Sierra juniper!
Post by: rockm on June 02, 2010, 08:24 AM
I've had luck getting rid of termite infestations using cotton soaked in insecticide plugged into borer holes in an old collected boxwood. After plugging as many holes in deadwood as I could find, I wrapped the trunks in plastic wrap and set the whole thing out in morning sun and left it for a day. It drove the termites out and killed them.

Borers are tougher and harder to get at. They tend to poke their heads out of their holes occasionally (I've had a few on collected cherry trees), usually in the morning. You have to go borer hunting with a sharp pointy stick or piece of wire. Sometimes you have to physically follow their tunnels through the wood--tearing up the trunk in the process--this can cause major or minor damage, depending on how deep the tunnel goes. Borers do tend to hang out in deadwood, but they will eat live tissue and can girdle a trunk in an afternoon...
Title: Re: Borers in my Sierra juniper!
Post by: John Kirby on June 02, 2010, 02:20 PM
A good systemic will kill them when they feed. John