Powderpost Beetle Problems

Here's a good description of a log house infested with powderpost beetles. February 9, 2008

What do powderpost beetles look like? Are they here in Missouri?

Forum Responses
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
They are very tiny, leaving a hole about 1/32" to 1/16" in diameter. They are in MO.

From contributor S:
I recently purchased a big stash of lumber that's been on sticks for years. I noticed a very small percentage has powder-post beetle holes and a few even had the infamous little piles of dust. The material is mostly cherry, soft maple and hard maple. Should I worry about an infestation in the entire lot? I know they have a long life cycle.

From Professor Gene Wengert, forum technical advisor:

From contributor K:
I have had a terrible time with powderpost beetles. My log cabin has them badly and we have treated and retreated with Boracare and also Sevin. The Sevin kept out spiders and ants too. Much of the lumber I saw and immediately sticker gets powderpost beetles very quickly. Some of the trees I saw - which come in various stages of dying from oak wilt - have them when I saw them. Is my property invested with them or is this a common problem? Are there other treatments than Boracare? What about the lumber I am sawing? Is there an economical spray to put on the lumber before you sticker it?

From Professor Gene Wengert, forum technical advisor:
You do not have the lyctid powderpost beetle, as it is seen only in hardwoods (mainly oak, ash and other grainy woods) and does not like wet wood and takes time between the laying of eggs and the hatching and then drilling exit holes.

You need to get these insects identified by an expert. It sounds like you have several different ones. Are the holes 1/16" to 1/32" in size? If so, do they have a dark ring around them? Once you have the correct ID, then control steps can be developed. In most cases, we control the insect before it gets into the wood, as once it is in the wood, control is extremely difficult.

Borates do not control these insects well as the treatment needs to soak into the wood, so submersion is often used. Brush or spray treatments do not work for control as they do not get deep enough. Further, if the wood gets rained on, the borates will leach out.

As the insects are inside the wood most of the time and only make a hole to exit, spraying Sevin will not work unless the insect is right there when you spray. Do you also spray the soil? This will work if the insects are in the soil at the time you spray. Sevin has a short lifetime of effectiveness, so you need to spray very often. Spraying the soil is better than spraying the wood, actually. Eliminating the wood trash around the air drying yard is also a key control feature, as such debris is a breeding ground.

From contributor K:
I have not sprayed the soil. I will try that. I have had it checked out and although I do not know the Latin, in my cabin they are the true powder post beetles. Tiny holes, the size of a pin, or maybe just slightly larger. Every log had them (cabin originally built in the 1830's, all white oak).

The Boracare was put on and the first treatment knocked out 90% and the second treatment almost all. I then varnished 4 years ago and now have 30 or 40 individual spots in the top of the cabin. However, in the basement, where it is moist, they continue to re-infest. Dust all over on the floor. You can see it coming out of the logs. I just can't get them out of the basement logs, and beams.

With my lumber, I don't know for sure of the beetle type. Most seem to be the same, pretty much only in oak and a little in the maple, and ash. There are larger borers occasionally, but they are only in the bark and outer sapwood. That all gets slabbed anyway. I have piles of firewood and slab wood close to my air drying piles. I will remove them, and treat the soil. I have a ton of black and red oak which I can't keep up to dying of oak wilt. As soon as they start to lose their leaves I am dropping them and hauling to my mill. They don't get cut immediately, and some are standing dead. Pretty much all of these have borers in them. They look similar to those in my cabin but I have not had a professional look at them like I did the cabin. Are there any other chemicals out there which work better than Boracare? Boracare was the one which all the pest control places said was to be used.