If several larvae are working in places as much as 18 inches apart, individual treatment is needed.
Fumigation
Treatment of a heavy infestation of powder-post beetles by spraying or brushing or by the slow-diffusion method is impractical where the wood is hard to reach; particularly when it is located behind plastered walls or covered by paneling or insulation.
Such an infestation can be controlled by fumigation—but this work must be done by a licensed fumigator.
Hydrocyanic acid gas or methyl bromide gas is used in fumigating. Each is very poisonous, and heavy dosages have to be used.
After fumigation, the building must be aired to make it safe for reoccupancy. The fumigating and the airing require 2 to 4 days.
Fumigation methods of the "home-remedy" type—such as burning sulfur candles—are ineffective because the fumigant does not penetrate the infested wood.
PRECAUTIONS
The insecticides mentioned in this leaflet are poisonous to people and to animals. Keep them where children and pets cannot reach them. Do not let them come in contact with the body. When applying them, wear rubber gloves, a cellulose acetate type of face-guard, and a rubber or leather apron. When spraying an overhead area, do not stand directly under it.