Advice for carpenter bees

I'm building a log cabin. The materials kit is being delivered next week, and I have some concern over providing a buffet for the healthy carpenter bee population that I have observed on my farm. The outhouse I built and put on the land six weeks ago already has half a dozen holes in it from carpenter bee drilling. We will be treating the timbers with a borax solution after the house is assembled which will take about 3 weeks or a month, but I need some advice on what I can do in the meantime. I thought about placing some scrap lumber in various places away from the homesite in hope to attract them and lure them away from where I'm building, but it got me thinking that maybe I'll just be baiting more carpenter bees from neighboring land to come over for the abundant nesting habitat.

Interestingly, there are two old dilapidated cabins on the land, one about 100-120 years old made from sawmill lumber, and the other approximately 150-200 years old made from hand hewn timbers with dovetail corners, that don't have any carpenter bee holes in them. It's got me wondering what carpenter bees prefer and why they choose some wood over others. The old cabins are made of oak and poplar, and there was some beadboard in one room that appears to be pine.

Any ideas?

Putting scrap wood around isn't going to help your situation, its going to encourage a breeding ground for the bees.
I would recommend that you get some carpenter bee traps and dispose of accordingly. you can find these for $20.
or build your own if you have the time.

I wonder if the original timber is denser cause it's old growth?

Wondering where you are James?   I am just moving on to my property in McNairy county TN.  I find all your posts of like-interests/questions to mine.  

Had Carpenter bees bad in spring 2018, when I was in Wayne county.  They went after old wood, new wood, soft wood, hard woods, painted.....not treated.  Never caught a one in the traps.

Carpenter bees do not appear to have any preferences for wood species. The only way I have found to be rid of the buggers is to caulk their hole at night or smash them if I catch them in the act of boring their new home.
I have had to deal with these creatures in several different locations, each with different species of wood being used and painted, unpainted, borax treated, no matter to the carpenter bees.
I talked to some professors and they told me the best thing to do was to fill the hole with some type of caulk to kill both the bee and the egg or I'd just have more of them to deal with.
I did find (by accident) that WD-40 sprayed directly on them will knock them out of the air so you can crush them.

I don't normally treat any pollinators with extreme measures but these guys have nearly killed me twice, so I will take them out before they have the opportunity to get me.
Redhawk

When I was a kid,  my grandfather would gather up the neighborhood kids, arm us with old tennis raquets.  I still keep one right outside the barn.

Hey Becky, I'm over west of the river also.

Here's a follow up on the carpenter bees. It seemed to me that they have a cycle, and when my log cabin went up, I really had little trouble with them. They had made Swiss cheese out of my outhouse before construction started and I'm guessing the ones in the vicinity had made their nests and we're done for the season. I did see a few buzzing about but they pretty much left the cabin alone. It will be interesting to see what happens this coming spring.

James Freyr wrote:
Any ideas?

When I first saw your post in the forum home page list, I got a real chuckle.  I suspected I knew what you meant i.e."Advice on dealing with carpenter bees"prior to clicking on it, but the first picture that came into my overly active mind was a classroom full of carpenter bees being "advised" by a carpenter bee school marm buzzing around with a pointer.  Sorry for wasting all of your time, but I couldn't not post it.

Yes I live in a log home, Yes, I have a plethora of carpenter bees on the homestead using my home as their nursery. I have more of an issue with the woodpeckers! They enlarge the bee tunnel entrances for an afternoon feast. The damage goes from a 1/4 inch hole to  2-3 inches

Carpenter bees prefer softwood species such as cedar, redwood, and pine. White pine is their absolute favorite. They do not prefer hardwoods. Unfortunately, most timber in the U.S. is pine, but if you can build with hardwood, do it.  

Barring this, painting or staining the wood deters carpenter bees somewhat, though a desperate, determined bee will find a way. If you do not want to use either of these chemicals, I have personally had success with using almond oil to coat the wood. Sweet almond oil is naturally repugnant to carpenter bees and some other insects, and will repel all but desperate bees. Beware, however, if you are in an area that has woodpeckers. Ants and other insects will get trapped in the oil, and you will find woodpeckers taking advantage of this and poking little dents in your wood. The standard sweet almond oil you find at the drugstore for use on the body works fine.

If none of this works, you will need to a: identify the female carpenter bees and eliminate them, or b: cut off the nesting site, as carpenter bees return year after year to the same site. The best method to identify the female is to watch who is boring. Female carpenter bees bore the holes. Male carpenter bees are the aggressive ones that dive bomb you. But they are full of bluster, and cannot sting. Female carpenter bees can sting, but are rarely aggressive. Kill the ones boring the holes using a wooden plank, a tennis racket, etc. and you prevent them from nesting. If a hole is already established, take a small wad of steel wool, shove it in the hole, followed by wood glue, and a 1-inch long piece cut from a 1/2 inch wooden dowel. The steel wool prevents any hatching bees from being able to escape the hole, or the mother from being able to bore back in. If you just cover the hole with wood filler or a dowel, they can cut right back through it. Dowels are cut to 1 inch because this is the depth the bee typically bores a hole before branching off to the side.

With all this in mind, it is important to note that even though the site of a wooden surface riddled with holes can be alarming, it would take many years of prolonged, intense carpenter bee infestation to cause structural damage to most structures. If you only have one or two carpenter bees buzzing around a fairly large house, there's probably no need to worry. Also, remember these are important, native pollinators.

I am finding the hole filling advice interesting.

When I was researching this it was said NOT do fill in the hole as the bees would simply bore a new hole out. Not true?

I should have been more clear in my post. Plugging the hole in this way prevents a hatched bee from leaving out of that particular hole, but you are right that it could bore a new one out if it had the strength and gumption. It seems people disagree on whether this happens. I imagine like other creatures, some bees will go the extra mile and chew out and some will die. If they do chew out, just plug the hole in the fall, after the bee emerges so it can't return to the site next year.

If you do this in the Spring when the mothers are establishing their nest, however, the more likely scenario is 1. you plug the hole before the female can provide food for and lay her eggs (in this case, she tries to find a new site, hopefully not your house) or 2. you plug the hole before she is finished constructing it, but not inside, obstructing the process.

Actively plugging the holes while the bees are working can and does work, as they will often abandon that site for a new one. But it's much more effective to kill the females because, as you point out, you could plug a few at the wrong time or miss a few and some bees just bore out.

If you're worried about this, I would just focus on killing the boring females and coating the wood to deter them. Then, any holes that do occur can be filled in the fall to keep bees from returning to the site.

It's sort of a game of whack a mole. Also, if you don't want to contend with angry bees, do the plugging at night. But I've done it in the day before and been fine, and getting them mad actually helps you be able to get at them with your racket.