What’s eating my deck?? A neighbor of mine recently started this conversation. So I thought it might be fitting to make an introduction – meet the Carpenter Bee (Xylocopa virginica. It’s name actually means ‘wood worker’ in Greek.) These are the shiny black, thumb-sized buzzers investigating everyone’s deck and house this time of year. They hover around the house at eye level challenging you to elementary school style staring contests. What’s up with these guys?
Image by Philly Honeyfest
Carpenter bees are one of our native superstar pollinators. These guys are often confused with bumblebees – due to similar size and color. An easy difference to distinguish is the fuzz. Bumbles are furry, Carpenters are mostly shiny. They are most active in spring and fall as they emerge, mate, and prepare nest cavities. If you like blueberries, tomatoes, melons or peppers these are some of the hardest working bees we have. Tomatoes in particular are known to set heavier fruit when pollinated by Carpenter bees. (Greenhouse growers raise these bees specifically for this purpose).
Even if you just like bird or wildlife in your yard, it is these pollinators who are doing the heavy lifting converting flowers into food for the other locals. The fact that they are natives makes them highly valuable. They willingly and happily live right in our yards to do their critical pollinating work, requiring nothing of us. Except maybe patience.
Image by Kansas State Extension
These are solitary bees who lay eggs in wooden tunnels, and stuff them with food for the future larvae. The females lay eggs in the wood cavities (also known as ‘galleries’ – sounds fancy, right?) and hang around to meet and defend their offspring who grow throughout the summer and emerge in the fall to feed before clustering for the winter. This time of year wooden decks, swing sets, fences and houses make attractive structures for them to investigate. Often the males will hover around existing nest sites, defending the area to other bees (and hummingbirds, humans, etc.) who might be moving in on their turf.
I get it. The wood boring part is annoying, especially when it is in something we value. Technically they are chewing – not eating or boring. They toss the resulting shavings outside or pack them like particle board along the cavity walls. My husband has a love/hate with these insects. So what to do? Offer alternatives. Carpenter bees greatly prefer soft, unfinished wood for their galleries. Where none exists, they will choose stained or treated wood but generally don’t recognize painted wood. They are looking for raw wood – so let’s give them some! Here are a few ideas:
- All natural – Leave a small pile of brush, wood pile in your yard. Don’t spray any chemicals or insecticides and see if they go the natural route. In reality this is what they are looking for.
- Make a condo – A simple unfinished block of wood with a bunch of holes drilled in it offers them an easier nest site than your deck. But size matters. Hole size should be 1/2” diameter and about 3-4” deep. If possible mount the block 3+ feet off the ground. Offer multiple size holes 1/8″ – 1/2″ to attract a range of different natives. Drill on the end grain to make it even more appealing.
- Give them their own house – Many local garden centers sell solitary bee houses that are quite attractive. Hang these early in the spring to give the Carpenters an easy choice.
Store-bought – Image by amazon
DIY condo – Image by Bugblog
What if they have already moved in to your deck? Carpenter bees are attracted to existing holes. These can and should be plugged with cork or dowels and sanded to match. Do this after the holes have been vacated! Otherwise, they will chew through your fix. When a neighbor asks what you are doing, you can casually respond “Oh, I’m just filling my galleries.” Carpenter bee traps exist but obviously kill the insects and reduce our native bee population. Use them as a last resort.
Insecticides are a terrible option. They kill all insects (butterflies, ladybugs, bees etc.) and the wildlife which feed on them (birds, toads, salamanders, etc). I realize many insecticides show the big NO mosquitos logo. But they fail to disclose that pyrethrins (the common and even organic sprays) are general purpose killers. These are nerve agents that kill all bugs dead – on contact. Spraying for insects in our landscapes destroys the food chain of wildlife, including us – especially if you garden, bird watch, or keep chickens.
I’m working on a separate post on mosquitos, as this is the time of year those neighborhood signs start popping up promising a bug-free outdoors. It might be a chance to save you some money and defend our superheroes. Keep an eye out for that and this spring, try offering our native bees the natural home they seek and they may just pollinate your garden and skip your deck.