Boric Acid and Carpet Beetle

Boric acid is an effective insecticide. It has been used for many years. Boric acid is extracted from the earth, so many people consider it to be a “natural” insecticide. It works as a stomach poison on the insects. The insect must swallow some of the boric acid for it to work.

Carpet beetles develop through a four-step life cycle. The eggs are hidden, so they usually cannot be treated with insecticide. Adult carpet beetles feed on pollen that they get from flowers. They gather outside in flowerbeds and on flowering shrubs. They move indoors to find a place to deposit their eggs. Adult carpet beetles die after they deposit their eggs, so they usually do not require insecticide treatment.

The immature beetles, called larvae, are scavengers. The larvae wander into dark areas, crevices, and even inside of walls. They feed on the dead insects, hairs, and organic debris that they find. The larvae also feed on stored food items that they find in pantries.

Carpet beetle larvae might not be attracted to insect bait, so it would be difficult to deliver boric acid to them in that form. Boric acid dust could be very effective in controlling carpet larvae, but only in certain locations.

Boric acid dust can be placed into crevices like the cracks behind the baseboards. These are places where the adult beetles deposit the eggs. When the eggs hatch, the larvae would be exposed to the boric acid dust.

This crack and crevice treatment requires some caution. The label directions for the boric acid dust specify that no dust can be left on visible surfaces. There can be no dust left where children or pets might have access to it.

Boric acid dust could be injected into the hollow void inside of walls. If there have been infestations of ladybugs, cluster flies, or boxelder bugs, the carpet beetle larvae might be feeding on the dead insects inside the walls. This void treatment usually requires drilling tiny holes in the walls.

Many people prefer to have dust treatments done by a pest control professional because of the risk of dust drifting out of the target area. Special equipment is usually required for these applications.

The homeowner can accomplish a lot of carpet beetle larva control by investigating to find their food source. Fabrics should be cleaned or washed. Items that will not be used often should be stored carefully. Infested food packages in the kitchen should be discarded. The pantry shelves should be vacuumed thoroughly.