Carpenter bees have taken up residence in my shed and stables. What is the best way to get rid of the bees without harming my horse if he comes into contact with the insecticide used?
A. Carpenter bees are important pollinators and do not aggressively defend their galleries, but the large bees are intimidating and, when abundant, can cause extensive structural damage. This can be compounded by woodpeckers that drill holes in the wood in search of carpenter bee larvae.
The weathered, slightly roughened surfaces of soft woods in barns and sheds provide ideal nesting sites for carpenter bees. Every spring, carpenter bees that have spent the winter in their tunnels emerge to expand established tunnels or begin to chew new ones, often nearby. These bees stock their tunnels with pollen as food for their developing larvae. Large aggregations of carpenter bees can accumulate in a structure over time.
Structures with exposed soft wood always attract carpenter bees, so management will be a continuous process. There are three major control options, which can be used singly or in combinations.
The most effective way of getting rid of a carpenter bee infestation is treatment of the active galleries with a residual dust. Also, the surrounding areas should be treated with a residual repellent to ensure that other potential areas will not become infested later in the season. After the treatment is administered and all activity has ceased, the previously infested areas should be painted or heavily stained so re-infestation will not occur in the future.
Encasing vulnerable areas that Carpenter Bees exploit such as facia, soffit and rake boards with Metal flashing, aluminum or vinyl with prevent future infestation.
Careful application of borates such as Timbor, or Boracare shows long term protection against these bees, ants, silverfish and mold and fungal decay as well. Timbor seems to be more effective as it crystallizes and remains closer to the surface. Care must be taken not to expose plants to these borates, they may injure or kill plants, shrubs and trees.