Those fat, fuzzy wood bees that you often see buzzing around wooden structures don't usually sting humans. But that does not mean you should just ignore them and continue to let them nest in your fence. Wood bees can build extensive tunnels through a piece of wood, which weakens the wood and may make your fence more likely to collapse or crack. So, if you spot wood bees near your fence, follow these steps to get rid of them and prevent them from returning.
Step 1: Spread the insecticide dust.
Visit your local home and garden store, and purchase a container of insecticide powder or dust that specifically states it will kill bees and wasps. The dust tends to work better than the liquid, since the liquid may be less effective if it dries before the bees encounter it.
Dress in long sleeves and long pants, and don a pair of gloves and a breathing mask. Then, follow the wood bees to see where the opening to their nest is. Usually, this just looks like a little drilled hole. Sprinkle insecticide dust around the openings of any such holes you find. Then, step away. Over the coming days, when wood bees return to their nest, they will brush against the insecticides and die.
Step 2: Plug the holes.
After you've waited about a week to ensure all bees have come into contact with the insecticides, it's time to plug the holes so new bees can't come take up residence in the nests. Take some little pieces of steel wool and stick them into the holes. The bees cannot burrow through the steel wool. Then, plug the rest of the hole with some wood glue or wood putty.
Step 3: Keep the fence painted or sealed.
To keep additional wood bees from invading your fence and building new holes, you'll have to make the fence less appealing to them. Bees won't typically burrow into painted wood, so make sure you re-paint your fence as soon as you start to notice any chipping or peeling paint. If your fence is stained, apply a sealer every year or so. The sealer will make it harder for the bees to bore into the wood, too. There are even specific sealers formulated with compounds to keep bees away, specifically.
Don't ignore the presence of wood bees in your fence. They may not harm you directly, but these bees can create a real headache if they bore through and weaken your fence boards. For more information about fence maintenance, contact Garrett Industries Inc or a similar company.