Carpenter Bees: Friend or Foe?

 Should we like Carpenter Bees or not?

I guess first of all, I need to confess that I find it hard to tell the difference between these two pollinators, the bumblebee and the carpenter bee. The photos that I have used here, I think, are of the carpenter bee. It seems they like to “rest” a lot on a flower or a wood post, and it was a wood post on the back deck where I found our “model” in some of these photos.

Carpenter bees pollinate many flowers and garden plants, but they are pests because they burrows holes in wood in our homes and yards so that they become a hindrance economically. Repeatedly boring into a wood structure can weaken it and cause a lot of damage over time.

The female carpenter bee tunnels into a wood structure, usually choosing untreated wood, and burrows about a 1/2 inch hole into the wood, going back a short distance then making a sharp 90° turn. There can be many branching tunnels through the wood, eventually weakening its structural integrity

These bee moms deposit an egg and enough food for the developing larva and then seals up that cell with a partition of cement-like wood chips, and then continues on and on making  six or more cells.

That egg develops into a larvae which eats the food as it grows and then emerges in August or September from that hole in the wood. Its adult life continues for approximately one year. It will live in the tunnel through the winter and , if it survives, emerge again in the spring to mate and repeat the whole process via another generation.

The carpenter bees do re-use tunnels from year to year and can become the pest we don’t want to see around  our homes, our fences, decks, etc. You can prevent some infestation by using treated wood, but sometimes they will tunnel into it anyway. They prefer unpainted wood over painted.

If you provide wood and tree stumps in a location in your yard, the carpenter may choose that wood over your other wood structures but there is no guarantee they will choose that wood. 

Carpenter bees prefer to reuse the old tunnels, so if you block those old tunnels, that will just encourage them to make new tunnels which further compromises the wood.  Ref: http://u.osu.edu/beelab/gardening-for-pollinators-2/

You can put out some untreated wood in a corner of your yard and hope they will choose to use that wood over and over. That way you still have the pollinator but not as much the pest.

And let me tell you why I think this is a carpenter bee.

Carpenter bees have a slick, shiny abdomen. Its thorax is usually covered with light hairs with a black dot in the center…bingo!

Males usually have a white face and females are the bees with black face.

Females are the only ones who can sting you, but rarely do unless provoked. Males are not able to sting, but they are aggressive and they like to dive bomb and buzz around you “checking you out.”

In fact, in the early morning garden, those males are the ones who buzz around your head and keep checking what you are doing in “their garden.”

Many mornings I have seen these buzzing around me as I weed or deadhead some plants.

And just this little nugget of information, those holes in your wood may have little stains around them. Those are “defecation stains” because the little buggers like to “jettison their load” before they go into their homes…..ewwww!

So make up your own mind, friend or foe. I guess I will say friend since they are pollinators, but I may change my mind if/when the back deck collapses.