Carpenter bees: a tale of solitude and tolerance

By on April 23, 2020

It’s the time of year when you may be seeing more carpenter bees around your house, especially if you’re around your house more these days. Carpenter bees are solitary though, so you won’t find them in hives – probably just one or two at a time in any given area.

Right now, lots of male carpenter bees are flying around in North Carolina, hanging out in old carpenter bee holes and preparing to mate. (Those holes are really nests. More on that is in a footnote.)

source: Dr. Mike Waldvogel (https://content.ces.ncsu.edu/non-honeybee-stinging-insects-in-north-carolina0

It’s kind of like a singles bar,” joked Dr. Mike Waldvogel. “They hang out and wait for the female carpenter bee of their dreams to show up.”

Waldvogel is an extension associate professor and specialist in structural and industrial pests in N.C. State’s Department of Entomology & Plant Pathology. He says soon, you’ll see more female carpenter bees flying around too.

Carpenter bees are pollinators, and they’re not aggressive, although male bees can be territorial with each other, Waldvogel said. They’re almost never trying to intimidate humans.

Only females sting, but “you’d probably have to grab one for it to sting you,” explained Patty Alder, the director & training coordinator at the NCSU Structural Pest Management Training Facility.

“They’re just out doing their thing in nature,” Alder said. “The bad thing is they nest in wood.”

The damage carpenter bees can do to wood is the normal concern. They are considered wood-destroying insects, and they can cause significant destruction in some circumstances.

“They do have to be taken seriously, but it’s a case by case thing,” Alder said. “Most of the time they’re just annoying and aren’t going to cause any structural damage.”

If carpenter bees do get into the wood around your home, the damage is usually just aesthetic.

“It’s a matter of tolerance – an individual’s tolerance,” Alder said. “If people can just leave them alone that’s what we recommend.”

Management/extermination
However, if carpenter bees are causing more damage than you can tolerate, there are some options to try to get rid of them. Alder and Waldvogel say carpenter bees are hard to get rid of though.

One option is to plug the holes they make.* You may want to plug the holes to prevent moisture buildup too, or to prevent woodpeckers from making the holes bigger and more significant.

Waldvogel said you can use a ball of aluminum foil to plug the hole and then caulk over it. If you’d like to use a chemical in the hole before plugging, a dust product such as Sevin dust is a good option he said. It’s important to be careful with a dust product and wear a mask.

It’s also important to be careful if you choose to try to spray your home for carpenter bees. It’s dangerous to spray without goggles or safety glasses and a mask. People are often tempted to spray over their heads, Waldvogel said, and much of the pesticide can fall on people instead of the intended target. The North Carolina Agricultural Chemicals Manual contains a list of chemicals for use against carpenter bees. (page 176)

Generally, spraying just isn’t really effective because of how hard it is to reach problem areas Waldvogel said. Also, since carpenter bees are solitary, you’re not getting rid of a whole hive of bees at once. More will likely come.

Carpenter bee traps may trap bees, but Waldvogel says there’s no evidence that they work on a large scale to actually reduce the amount of damage carpenter bees do. Painting or varnishing wood usually deters carpenter bees, but only until the paint or varnish wears off.

If you decide to have your house (or other structure) inspected or treated for carpenter bees then you should verify with the NCDA&CS Structural Pest Control & Pesticides Division that the exterminator is currently licensed with a structural pest control license that includes a W (Wood-Destroying) phase. This will help to ensure that the individual performing the inspection and/or treatment has been trained in identifying carpenter bee evidence and in the use of properly labeled pesticides.

You can visit https://www.ncagr.gov/SPCAP/LicenseSearch.htm or call the division at 919-733-6100 for more guidance.

source: NCSU Apiculture (https://content.ces.ncsu.edu/non-honeybee-stinging-insects-in-north-carolina)

Identification
If you’re inclined to tolerate carpenter bees or other pollenating bees but have concerns about other flying insects that can sting, it helps to be able to tell the difference. Carpenter bees are most often confused with bumblebees. Carpenter bees have smooth bare abdomens, while bumblebees have hairy abdomens. Bumblebees also nest in the ground where you may step on them, as opposed to wood. N.C. State Extension has an online guide to many stinging insects in North Carolina that aren’t honey bees. (If you need help identifying honey bees, search for other online resources.)

Alder’s advice about dealing with stinging insects is similar to dealing with carpenter bees. Essentially, tolerate them as part of nature unless they pose a threat.

“If it’s anything that nests in the ground or anywhere that my family or I would be stung, it warrants getting rid of the nest,” Alder said, describing her personal litmus test.

Both Alder and Waldvogel say it’s important to remember that carpenter bees and other bees are important to nature as pollinators.

*The holes carpenter bees make in wood are actually nests carved out by female bees. The hole you see is just the nest entrance. Nests can be about six to seven inches long/deep, usually along the grain of the wood. A female carpenter bee will lay her first egg at the far end, then build a partition with a ball of pollen, then lay another egg and build another partition with more pollen. She will lay about six to eight eggs with a partition between each one. Because each nest has several cells beside each other in a row, carpenter bee nests are often called galleries.

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