To kill carpenter bees effectively, follow these key steps:
1. Use Insecticides
- Spray a residual insecticide directly into the carpenter bee holes and on wood surfaces where they bore. Effective insecticides include Cyzmic CS, Demon WP, FenvaStar EcoCap, or similar wasp and bee aerosols. Spray at dusk when bees are inside the tunnels for best results. Repeat treatments 2-3 times in spring at 2-4 week intervals for severe infestations
- Apply insecticidal dust (e.g., Tempo Dust, Delta Dust, D-Fense Dust) deep into the tunnels using a hand duster. Dust kills larvae and adult bees inside the nest
2. Plug the Holes
- After insecticide treatment, wait 24 hours and then seal the holes with wood putty or caulking to prevent re-entry. Female bees can reopen holes if not treated first
3. Use Alternative Methods
- Vacuum bees at dusk when they are inside the nest to remove them physically
- Spray essential oils like citrus, peppermint, or eucalyptus as repellents (these do not kill but deter bees)
- Boric acid mixed with water sprayed into holes is toxic to carpenter bees and can kill them within an hour
- Aerosol carburetor cleaner or pyrethrum spray can also kill bees inside the nest
4. Prevent Future Infestations
- Paint or seal exposed, weathered wood as female carpenter bees prefer untreated wood. Adding insecticide to paint or wood filler can provide residual protection
- Replace heavily damaged wood with treated wood to discourage bees from returning
- Consider carpenter bee traps to catch and remove bees
Safety and Timing
- Apply insecticides at dusk when bees are inside the tunnels to maximize contact.
- Wear protective gear when handling chemicals or disturbing nests.
- For large or hard-to-reach infestations, professional pest control services are recommended
By combining insecticide sprays and dusts with sealing and preventive measures, you can effectively kill carpenter bees and reduce damage to wood structures
