Powder Post Beetles in Plywood

Amazingly, the bugs are not killed by plywood manufacturing methods, and can lurk inside plywood for years. October 27, 2011

I have a cabinet we made out of prefinished birch plywood with a 1/4" skin of vc white oak. The customer showed me that there were powder post beetles in the white oak plywood. I was surprised to find these in plywood. Has anybody ever heard of this before? How do we get rid of it?

Forum Responses
(Cabinetmaking Forum)
From contributor S:
Your plywood supplier should pay to replace the cabinet. I have never heard of wood boring insects in plywood before. Replacing the cabinet would probably be easier. That is unless you want to fumigate it, place it in a kiln, or freezer.

From contributor G:
I would tell your client he better check out his house because he likely has an infestation. With the heat and pressures they press plywood at I don't see how bugs or eggs would survive. It had to happen after it was shipped out from the factory - possibly in the storage area of your supplier.

From contributor M:
Powder Post Beetles can be dormant in the core of your plywood right from the tree before it was cut. We had exactly the same situation - some hickory plywood had a core originating from S. America. The customer began to notice very tiny holes appearing in the 1/4" plywood skin on the finished ends of his wall cabinets. We are actually still in the process of removing the skins and replacing them. Big headache! Our plywood distributor replaced the plywood and assured us they will pay the labor for removing the cabinets, replacing the sides and re-installing. We are actually seeing the beetles as we remove the 1/4" skins. They are exiting the plywood through the tiny holes they bore. They seem to die once out in the light. By the way - we are doing all this work outside our shop - I don't want any of the plywood in my shop as I'm apprehensive of infestation into our existing supplies of wood.

These bugs did not penetrate the plywood after the plywood was fabricated. They can be dormant in the core for well over five years, and the heat and pressing of the plywood does not kill them! Anyone in this situation has my sympathy. This is without a doubt a huge mess for any involved, to say nothing of the damage caused to customer relations. Our client is sympathetic to our situation - our plywood salesman actually met with him and discussed the remedy. To date things are going smooth - we hope to have the cabinets sprayed and back in next week. The replacement hickory plywood has an MDF core.

From contributor R:
I did a 16' x 10' custom, 3" thick, ash hardwood, butcher block, "U" shaped, radius cornered, 8/4 milled arm rail, bar top about a year ago. Two weeks after the client moved in and turned the heat on, they came to life. I spoke with an exterminator, and he told me that the powder post beetle can lay dormant for up to ten years, and just wait for the right temp to come to life. He also said that if the material were 3/4" thick, he could use a syringe, and put in a gel that would fill the voids and kill the infestation.

Unfortunately for me, the material used was too thick, and he would not guarantee the client; so, I got to eat most of the re-build. If you are in with a good builder, he probably has a good bug man. Give him a call, it may save you more money than the re-build.