I have most likely 30 plus Carpenter Bees, it seems like a lot more. They are centered around my back deck. It appears they are drilling into the bottom areas of the deck.

This is what I have tried to far.

1. I bought Carpenter Bee poison spray, I tried just spraying it around the area to see if they would just go away.

2. It says "kills on contact" well I sprayed dozen of them and they just seem angry. I did not see dead bees anywhere the next day and they were not dying on contact.

3. I have went out several times trying to spray water around at them, to try to scare them away,

4. Ok, I sprayed water hard at them, knocking them to the ground and stompped them. Ok I got rid of about 12 of them today, but this evening, it does not even seem like I killed any, they are still there in swarms.

If they would just damage something other than my deck, I don't mind them being in the back yard. LIke I would even put a post in the back to make them a home.

Carpenter Bees are common at my office too.

1. squirt boric acid powder into the holes that they have drilled,
2. fill the holes with wood putty and repaint.
3. sit on your back deck with a cold beer and a tennis racquet and smack them when you can.

The key is killing the ones you can AND filling their holes as fast as they make them. Do that religiously for this season and they'll likely not come back.

I thought this link would be helpful:

Carpenter Bees | University of Kentucky Entomology

They do bore a decent size hole, so those do need to be patched.

I got from this link they like to bore into UNPAINTED surfaces, which usually is the bottom of railings, so may need to paint those surfaces after all holes are filled.