Carpenter Bee Control

By Walt Cline

Get Rid Of Carpenter Bees

If you have an active carpenter bee infestation, follow these guidelines to exterminate them.

    carpenter bees
  1. Spray a residual insecticide in the areas where the bees are active.

    Recommended Insecticide Products: Cyzmic CS Insecticide, Demon WP , and FenvaStar Cap.

  2. Apply Residual Insecticide Dust in Carpenter Bee holes and galleries with a duster.

    Recommended Dusts: Tempo Dust and D Fense Dust

  3. Save 10% on Carpenter Bee Kits, use code: carp20

    Tempo Dust is a preferred dust for carpenter bee control. We carry a line of dusters that are handy for applying the dust. B&G Bulb-R M1150 and JT Eaton's Bellow Duster. The Bulb-R M1150 Duster has a curved tip that can reach into the carpenter bee holes very effectively.

  4. Plug the holes (caulk or wood putty) during the fall months. If you plug the holes too soon, the carpenter bees may make another hole to exit.

1. Residual Liquid Treaments To Spray

Spray the areas where carpenter bees are boring in wood with Cyzmic CS, Demon WP, or FenvaStarCap. Sometimes the bees may bore into painted or varnished wood. Their holes are usually located on the underside of wood surfaces including siding, soffits, overhangs, decks, fence posts, fascia boards and window frames. We recommend spraying twice during the spring months at intervals of 3-4 weeks.

For severe infestations of carpenter bees on cedar and log structures, you may need to repeat the treatments more than twice. We suggest an interval of two weeks for spray treatments. After each spray treatment, apply D-Fense Dust or Tempo Dust to all possible carpenter bee holes or entry points.

If protected from the elements like rain, this residual insecticide will last 2 to 3 months. If applied in late winter the treatment will stay active through most of the carpenter bee season.

2. Using Dust In Carpenter Bee Holes

If you have a current infestation, dust with Tempo Dust in as many carpenter bee holes as possible. Fill the B&G Dust-R Duster or your chosen duster 1/2 way with dust and dust into the openings.

Although their holes appear only an inch or two deep, it usually extends at a 90 degree angle. The B&G Dust-R Duster comes with a curved tip that will fit into the 90 degree angles easier. The female will turn 90 degrees and bore a channel from 6 inches to as long as 4 feet. This channel serves as a main corridor from which she will drill small chambers a few inches deep. These chambers become egg holders. She will deposit an egg, bring in some food, and then seal it off to ensure the egg's development.

It may be difficult to treat each individual gallery with dust, aerosol or liquid residual insecticides, as you can see by the , but is important if you have a current infestation.

3. Plug Up Carpenter Bee Holes

carpenter bee holes

You can plug up the entrances with plugs, cork, putty, or use caulking compound. We suggest sealing the holes with wood putty, since you can paint over the wood. Plug the holes after all the bees are killed. A safe time to plug entrances is in the early fall months. If you plug up the entrances too early, you will stop the carpenter bees from passing through the insecticide dust, and they may chew new openings in other locations. The following year, spray early to prevent further boring.

Getting rid of Carpenter Bees depends on the timing of the year. You can prevent carpenter bee infestations if you tackle the situation early enough.

4. Carpenter Bee Traps

For those considering a non-chemical approach to carpenter bee control, we recommend the Best Bee Trap. This trap is specially designed to attract and trap the carpenter bees. If you have an existing carpenter bee infestation, hang it directly over the carpenter bee holes. If you do not have an existing infestation, hang the traps at peaks and corners of your home, preferably on the sunniest side of your house.

How To Prevent Carpenter Bee Infestations - Spray Early (early spring months)

  • Prevention is the operative word for carpenter bee control. Prevent them before you have to get rid of them. Carpenter bees most often prefer to bore holes in the wooden areas that receive the morning sun or afternoon sun.
  • Carpenter Bees attack unfinished wood under decks, sills, and decks first. Varnish or paint these wood surfaces to make them less attractive to these bees. A fresh coat of paint is unattractive to a Carpenter Bee.
  • Seal as many exterior openings as possible. The Carpenter Bees are looking for cracks that will protect entrances. Seal and caulk these cracks and crevices.
  • Carpenter Bees will reuse holes from the previous season. Cauk these holes in the fall, after the carpenter bees have emerged.
  • Carpenter Bee prevention and extermination is usually best done before nesting activity gets started. If you do not have a chance to paint or varnish the unfinished wood, before the bees bore into the wood, spray the unfinished wood in these vulnerable areas (under rail sidings, under decks, around window sills, etc) with a good residual spray such as the ones listed below. The best time to spray preventively for carpenter bee control is spring time. Nesting and the rearing of young carpenter bees occur in the late spring or early summer. These residual insecticides will last 2-3 months, continue retreating until the fall season.

woodpecker Woodpeckers may be peck in to carpenter bee tunnels in the wood trying to eat the bee larvae.

Spray Cyzmic CS Insecticide into the carpenter bee holes and on the wood in the spring. This will discourage the carpenter bees from attacking the wood. This in turn will discourage wood peckers.

Recommended Residual Insecticide Concentrates for Carpenter Bee Prevention

  1. Cyzmic CS or FenvaStar EcoCap - Will not leave a visible residue.
  2. Demon WP - Will leave a visible residue seen against dark surfaces
  3. These residual insecticides will make several gallons of finished product and can also be used to treat a broad variety of insects. The B&G Dura Sprayer is both durable and economical and makes application of insecticides easy.

Carpenter Bees

Carpenter Bee Carpenter Bees can look like Bumble Bees; large, with yellow and black patterns. They are about one inch and may have some metallic reflections ranging from dark blue, yellow, green or purple tints. Their abdomens are shiny, which are different from Bumble Bees, which have more hair. They are commonly sighted in the spring hovering like a helicopter around eaves, porch rails, and under decks. Some times carpenter bees are called "wood bees", because they bore into wood. Carpenter Bees do not eat the wood for nutrition. Carpenter bees, as pollinators eat nectar and pollen from flowering plants.

The female carpenter bee bores a channel or main corridor in wood from 6 " to as long as 4 feet to lay their eggs in divided areas called "galleries" or "cells". She deposits an egg into these galleries, and brings them a mass of pollen for the newly hatched larvae to feed on, and then seals them all off to ensure it's development before she repeats the process for the next egg. Carpenter bee galleries have entrance holes on the wood surface, continues inward for a short distance and turns torun in the same direction of the wood grain.

Although, they are a wood boring insect, they are not considered a true structural pest. They do not spread through out the entire structure, but prefer unpainted or finished wood.

For More Information: Carpenter Bees

Picture above by (Own work) [CC BY-SA 3.0 (], via Wikimedia Commons

Signs of Carpenter Bee Infestations

carpenter bee hole Carpenter Bees make holes about 1/2 inch in diameter. They prefer unfinished wood and can drill and create tunnels in seasoned hardwoods, softwoods and decaying woods. Look for "frass", that looks like sawdust from these drilling areas.

For More Information : Carpenter Bee Identification and Signs