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