Treatment for Carpenter Bees

Carpenter bees are not dangerous but they can do extensive damage to exposed wood, particularly wood on homes. They bore holes in wood that are comparable to work done by an electric drill and lay their eggs in the tunnels. Successful treatment for carpenter bees involves several separate procedures that eliminate the carpenter bees present and prevent others from choosing the same nesting location.

Sprays

Using sprays has limited value in the treatment of carpenter bees because sprays repel the bees before they land on treated surfaces; instead of killing them, it will simply cause them to bore holes elsewhere. There are spray products available claiming to eliminate carpenter bees, but because carpenter bees bore most of their holes on exposed wood surfaces, spray products are nearly useless because they lose their active life when exposed to direct sunlight and rain. If applying a spray to aid in prevention, use a microencapsulated residual insecticide; these products encase the insecticide in tiny capsules that are broken upon contact, thus increasing their active life.

Dust

Injecting insecticide dust into the holes of carpenter bees is the best procedure to kill carpenter bees and it is the one used by professional pest control firms. Injecting small amounts of dust is the key, so the bee will crawl through the dust and soon die. Applying dust will not prevent carpenter bees from boring holes in the wood but will simply kill bees present.

Prevention

Painting exposed wood surfaces helps prevent carpenter bees from boring, and using light colors is thought to improve results, but painting is no guarantee. The best preventative measure is to cover exposed wood with material that carpenter bees will not bore through, such as vinyl or aluminum.

Equipment

Spraying should be done with a handheld pump sprayer. Make sure that the spray nozzle is adjustable to allow a stream spray. Carpenter bees often bore holes well off the ground and a fan spray will not reach high enough. Use the stream setting and a fully charged (pumped) sprayer to apply a coating of residual insecticide where carpenter bees are known to bore. Inject insecticide dust into carpenter bee holes using a dust stick, which is an insecticide duster on an extension pole, by inserting the tip directly into carpenter bee holes and applying light amounts of dust.

Repair

Filling carpenter bee holes should be done for aesthetic reasons and to prevent carpenter bees and other pests, such as carpenter ants, from using them once the bees have been killed. For extensive damage, this can be accomplished by removing and reinstalling new wood. For limited damage, the best way to fill carpenter bee holes is to purchase small diameter wooden dowels and trim them down with a knife so that they just fit inside the holes. Lather them with wood glue, slide them in the holes and fill the edges with more wood glue. Once the glue dries, sand and finish the surface to match the home.

References

• Ohio State University Extension: Carpenter Bees
• Clemson Cooperative Extension: Carpenter Bees
• University of Kentucky College of Agriculture: Carpenter Bees