Carpenter bees come every summer and many homes have strips of wood under the roof or on the deck that have a line of holes in it. These bugs are aggressive. How much damage can they do? Many also ask, ‘What can I do?’
Carpenter bees are not considered “wood destroying” insects on the same damaging scale as termites or carpenter ants but if they pick your house they sure can be an annoyance. They’re called carpenter because they leave little piles of sawdust under where they are working like a human carpenter would using a saw on a board dropping the dust just under where the cut is made. They are just flying big bugs that look like bees but don’t make honey.
The males do not sting but the females will bite if handled roughly. Their resemblance to bumblebees is close. Bumblebees have a hairy abdomen with some yellow markings but only examine a dead one for identification. The only difference between the two for our purposes is behavior.
It’s the females that cut the perfect holes, about 3/8ths of inch in diameter, into raw or stained wood or on wood that the paint film is thin or damaged. It looks like a .45 caliber bullet hole. They love cedar but any trim or siding of natural softwood wood will do for them. They turn 90 degrees after they’ve bored in about a 1/4 or 1/2 inch into the board and chew a chamber into the wood along the grain for about 4 to 6 inches for a brood chamber — all at the diameter of the surface entry hole. There they deposit larvae sealing them up in the end of the chamber with a paste of chewed up sawdust, pollen and bee spit. The larvae that they deposit in the chambers take from one to three months to mature, then out they come — full grown carpenter bees.
Sometimes the mother bees will re-use old chambers rather than make new ones but even though the boring that they do tends not to severely damage the structural integrity of the wood in question, some trim boards look like they have been shot at with a pistol they have so many perfectly round bee holes on them.
You’ll see carpenter bees buzzing about the boards and flying around and diving fast in an aggressive manner and they’ll chase you. The males doing this can’t sting but are hoping any potential predators of the larvae they are protecting don’t know that. Avoid any diving bee, but woodpeckers apparently prize carpenter bee larvae as a delicacy. If the unlucky combination of a carpenter bee infestation coupled with a woodpecker discovery takes place at your house, the woodpeckers will punch some nasty holes into your wood trim looking for lunch and will make a racket doing it. Now your wood trim will really get damaged.
The most common approach to carpenter bee control is to seal the holes and paint the wood. Some suggest dusting the holes with Sevin. If you use caulk on the holes and it’s soft they will bite right back through it so the best stuff to use is plastic wood which, if you’ve ever used it, you know it gets harder than the wood itself. The other commonly used wood putty — Water Putty — works too.
The paint must be a true surface film and not merely a wood stain. This presents a dilemma to some as one of the most popular woods with both carpenter bees and homeowners alike is cedar and cedar looks best stained.
Also, stuffing the bee holes with steel wool or nailing common window screening over the holes to discourage these bees may work. Wrapping the trim with vinyl or aluminum is a drastic but successful tactic. If you get into wood replacement be sure that you paint the wood well before putting it up — that’s for both bee and rot protection.
Flying wasp sprays are effective but you’ve got to chase them around squirting poison at them to actually kill them. Pest control companies offer a spray treatment for those who don’t want to mess with the bees themselves. It’s not too pricey.
For information on eradicating carpenter bees, contact EHS Pest in Norwood.