Carpenter bees can be successfully controlled with Carpenter Bee Insecticides Active nests containing eggs, larvae, or pupae can be treated with liquid or dust formulations of insecticides or desicant dusts. Carpenter Bee Insecticides are made of Liquid formulations containing permethrin and cyfluthrin and dusts containing boric acid are currently labeled for use against carpenter bees. Desiccant dusts are inert dusts combined with absorptive powders (diatomaceous earth or boric acid). This dust destroys the insect by abrading their protective outer body cover, causing them to dry out. Desiccant dusts are low toxic to humans and animals. It does not lose its effectiveness, provided it is kept dry.
Carpenter Bee Insecticides should be used with precaution. Always follow the directions, wear protective clothing, use glasses or goggles. Avoid inhaling these chemicals, as they can cause serious lung irritation. The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticides.
To have any effect of the chemicals, you must inject directly into the galleries. They shouldn’t be just sprayed on to the surface.
Experts do not recommend marine paints. They are outrageously expensive and contain excessive toxins. If toxic paints are discovered on a house, an expensive removal process will have to be followed if you so decide to sell your house.
Treating the entrance hole with an Carpenter Bee Insecticides spray or dust containingcarbaryl(Sevin), cyfluthrin or resmethrin among other chemicals, can reduce future carpenter bee activity. North Carolina Agricultural Chemicals Manual gives a list of chemicals that could be used against carpenter bees. Carpenter Bee Insecticides sprays kill both adult bees as well as any offspring that other methods would leave behind to emerge later.
Carpenter Bee Insecticides dusts (Tempo 1D, DeltaDust, Zep Termite Ant Killer) can be puffed into the nest holes in the evening when bees are resting. A dust will not soak into the wood as a liquid should, but will spread around the nest gaining better results. Bees should have access to the entrance hole for about twenty four hours, and the bees will spread the dust. Home owners may not have access to insecticidal dusts labeled for wood treatment. Home owners will have access to sprays (Bee/wasp killer aerosols, Ortho Termite and Carpenter Ant Killer, Bayer Advanced Home Pest Control Indoor and Outdoor insect (bifenthrin) Killer ready-to-use pump (cyfluthrin) or others) into the nest opening.
Carpenter bee nests can be treated with a dust like Drione from the outside. Drione will kill all the females after a couple of days and you can seal the holes with corks. The remainder of Drione left plugged in the nest, will kill all the young when they hatch. Drione also does a great job of adhering to the surface and only a small quantity of dust is needed. If new carpenter bees hang around trying to drill new holes, cypermethrin can be applied as a repellent. Cypermethrin and NBS insect repellent sprays are hated by carpenter bees. Cypermethrin and NBS, sprays prevent the bees from drilling newholes. Cypermethrin is stronger than NBS. Cypermethrin lasts longer. With weaker sprays, you will have to repeat every week or two.