The months of May and June are typically filled with calls from clients on Carpenter bees. The female nests in wood and creates a distinctive gallery for her eggs. The opening will be a one-inch diameter hole and will take a right turn and go for about 4 to 5 inches within the wood’s grain. The evidence of holes and yellow staining from both the female’s frass and pollen will indicate such an infestation. Decks, rafters, stairs, barns, banisters and windowsills are all likely areas to be infested.
Carpenter bees are very territorial and even though the males cannot sting, they will aggressively defend the gallery, while females can sting, but it is rare to be stung by one. Carpenter bees will continue to return year after year to areas where they have previously nested or emerged from a nest as young adults. Unless the wood is sanded down and painted well, females will continue to drill in the same area.
Applications of dust or liquid insecticide labeled for the carpenter bee can be placed within the gallery. After a day or two the gallery can be sealed and plugged with wood putty or caulk.