Do you have a cedar or redwood swing set? If so, there’s a good chance that you’ve seen carpenter bees buzzing around, or noticed their tell-tale holes in your set. Here’s everything you need to know about these bees and how to keep them from ruining your outdoor fun.
What are carpenter bees?
Here are 4 facts about carpenter bees:
Carpenter bees are large yellow and black bees that look like bumblebees. However, unlike fuzzy bumblebees, carpenter bees have a large, shiny, solid black abdomen. Male carpenter bees, who have a whitish spot on their faces, are the ones most likely to dive at you. Don’t be scared of them, though – the males have no stinger. Females have stingers, but won’t use them unless provoked.
Carpenter bees get their name from the perfectly round, half-inch diameter holes that they drill into wood for their nests. They come out of their nests in the spring to mate and build new nests.
Female carpenter bees use their sharp teeth to dig perfectly round tunnels in soft woods like cedar or redwood. After they lay their eggs in these tunnels to mature, the females die.
The new bees come out of the tunnels in the late summer to feed on plant nectar then return to the tunnels for the winter.
What damage do carpenter bees cause?
Carpenter bees prefer to dig their nests in swing sets made of soft woods like cedar or redwood. Pressure-treated pine is not an attractive option to them.
If your infestation is limited to just a few tunnels, you don’t have to worry about them taking down your swing set. Although they do dig into wood, carpenter bees won’t steadily destroy your swing set like termites or carpenter ants might. (You do still need to worry about them stinging your kids though!)
A few things to look out for:
Funny holes.You’ll usually find holes going into the wood for about an inch, at which point the tunnel will turn and follow the wood grain for about six more inches. There may be multiple smaller tunnels.
Sawdust.You might also find fresh sawdust or fan-shaped stains outside the hole.
Scraping sounds.You may hear scraping sounds from inside the wood.
If your infestation is widespread or has been going on for many years, the large number of tunnels can cause the following problems:
Structural damage.You would need to have a huge number of tunnels to make a swing set dangerous, but the woodcan weaken over time.
Water damage. Moisture getting into the tunnels can make it rot faster.
Stains. Carpenter bee feces can stain wood.
Woodpeckers. Birds that eat insects are drawn to the sound of bees nesting and larvae. These birds can cause much more serious damage.
What can you do to prevent carpenter bee damage?
Here are some tips to convince carpenter bees to find a home far away from your swing set:
Use pressure-treated pine.Treated wood is less attractive to, and therefore less prone to carpenter bee damage.
Paint or varnish your wood.To discourage carpenter bees, paint ALL surfaces of your wooden swing set with a sealing primer and at least two coats of paint. Stains and varnishes are less effective, but better than no coating at all.
Fill cracks. Fill all cracks, nail holes, divots and splintered wood with caulking or putty before painting. These openings in the wood are appealing to bees.
What can you do about existing bees?
Listen, a few bees may not take your swing set down, but that doesn't mean you want them around! Here are some tips to get rid of the bees swarming around your set:
Fill deserted holes.When carpenter bees leave their holes in the spring and fall, fill their holes with a piece of steel wool, a clump of aluminum foil, a dowel and wood glue or caulk. Paint over the holes once they’re filled.
Treat active holes.If there are still carpenter bees in the holes, you may want to treat them with insecticide first. Pyrethrum, boric acid, carbaryl, or any spray labeled for flying insects will work fine. The best time to do this is at night when the bees are at rest, or in the early spring before they’ve come out to mate. Put the spray or powder directly into the hole. Stay alert for angry males who might come out of the holes. Then fill and paint over the holes the following day.
Avoid wood treatments. These won’t do much good since the bees don’t actually eat the wood.
There is no way to guarantee that you won’t get carpenter bees in your wooden swing set, or that you’ll be able to completely eradicate them once you have an infestation. However, by keeping watch over your swing set to and following the steps outlined above, you can help ensure minimal damage.