Need Cheap or Free DIY Carpenter Bee Killer

I'm about to go crazy tonight. We've got a huge problem with carpenter bees making holes around our front porch, and I'm about ready to go into battle against them. Normally I would call Hubby's best friend who is an exterminator, but he's out of town for a month long vacation. I've been looking online and reading about demon wp pesticide, but I was hoping to find some DIY carpenter bee killer that won't cost me much. Anyone have any suggestions before I pull my hair out?