Ridding one's house of powderpost beetles

What to do upon discovering an infestatoin of powderpost beetles. 1998.

by Professor Gene Wengert

I purchased a table from a roadside vendor in Oregon about two years ago. It has a menzanita base and five top plates of myrtlewood. Recently small piles of dust have been appearing on the floor under this piece. They are from small holes in the menzanita base wood.

I bagged the table and sprayed Raid in the bag and let it sit for two weeks but this did not stop the problem. What is the cure for these pests and will they move to other wood in the house?

If the holes are quite small (under 1/16 inch diameter), then you have the lyctid powderpost beetle, which is nothing to fool with because it can be very damaging.

The holes are exit holes and usually show up one to two years after the eggs were laid. The beetles will now try to find another place to lay eggs--nooks or crannies of HARDWOOD lumber. They will not affect the house construction members as they are almost always softwoods--pine, fir or hemlock. But these beetles can get into other hardwoods in your home--shelving maybe, oak floors, frame of upholstered furniture, decorative hardwood paneling and plywood, hardwood doors, and so on. They cannot get into wood that is thoroughly varnished or coated with a film forming coating.

When you spray the wood, it will not kill them as they are inside the wood. Fumigation will work, but the gas is so dangerous that you could not do this at home--a licensed person is required. Spraying the area around the wood doesn't work too well, as when new ones hatch, they will not be killed by previous spraying.

You can kill them (bugs and eggs) with heat--over 130 F for 24 hours.

I suggest that you immediately remove the piece from your house. You might check you homeowners policy to see if it covers damage from noxious insects. Once the bugs are widespread, then fumigation of the entire home is the only reasonable solution--but in any case, if you have had them spread, you have months to do something, so don't panic or be pressured into an immediate solution.

Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison.

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