Diagnosing the Problem
1) Are they Honey Bees?
There are a number of insects that people call bees. Some are bees, some are wasps, but many of them are not Honey Bees, the subject of this page.
a) Are they about 3/4 inch long? If much larger or smaller, they aren’t Honey Bees. Very large bees are ordinarily carpenter bees. Very small bees could be any of a large number of species of mainly non-social bees.
b) Are they yellowjacket wasps? Yellowjackets are about the same size as Honey Bees, and nest in moderate-sized colonies. They are dark black and bright yellow, with obviously defined black and yellow bands (see my wasp site). Honey Bees are more brownish, and fuzzier, with less well defined bands (see graphic above)
2) Are they foraging bees, a swarm in transit, or an established colony?
a) When you just see many bees flying around flowering plants, they are most likely just foragers visiting the flowers for nectar and/or pollen. Foragers can sting, but normally only do so if they are trapped or crushed. There’s little than can be done to deter foraging bees except to remove the flowers.
When you see a cluster of bees hanging in a tree, ranging in size from a baseball to bigger than a football, it is probably a swarm. Swarming bees are bees that have left their original colony, with the old queen, and are looking for a suitable cavity in which to form a new permanent nest. When they find one, they will move on again en masse, usually in a few hours to a few days after they land.
The tens of thousands of flying bees in a swarm taking off or flying is a very dramatic sight, but usually not a excellent danger. Considering that the bees have little to defend, swarm bees are usually fairly docile (but not always, so don’t disturb them). If you can see the edges of wax honeycombs sticking out of the cluster, or when it remains in place for a week or more, it is probably an established colony (see c)
c) If you see many bees coming and going from the same place (usually a hole that leads to their nest cavity, but in certain cases you will just see them flying out of vegetation at one place), they are probably an established colony, living in nest made of beeswax combs that they build, usually, but not always, inside a cavity.
These are the most troublesome, because they are permanent, and because the bees are more likely to defend their nest by stinging. I ordinarily advise individuals to remove established colonies as soon as they can after they discover them, because the honey bee colony will continue to grow, build more comb, store more honey, and become more defensive. Regrettably it is not terribly simple to remove an established colony inside a cavity.
Dealing with Honey Bees in the wall
Removing a bee colony from a wall is probably not something you want to do yourself. I recommend calling a professional (see Bee Removal resources page) You want to get someone who’s the equipment and experience to deal with bees, and do it right.
Not all pest control operators will do all that I recommend here, and I think you are asking for trouble when you just have the bees killed and nothing else, so persist in locating someone to do the complete job.
Honey Bees – to Kill Or Not to Kill?
Bees could be removed alive from the wall by someone accustomed to working with them but it’s somewhat challenging, and there is a greater risk of someone getting stung.
Most pest control operators do not have the beekeeping expertise to do live bee removal, and besides, then they would have a colony of bees that they do not want either. On the other hand, bees are advantageous insects, and many individuals are reluctant to just have them killed. Some bee removal companies do live bee removals.
Also, you may be able to find a beekeeper willing to do it. This can be an fascinating sideline and service for a hobby beekeeper (commercial beekeepers are nearly definitely not interested). Never expect it’ll worth it to him or her just for the bees; it is a big job, the honey bee colony will probably have to be requeened after it is done, equipment built for the honey bee colony to live in, etc.
When looking for a person to do a live bee removal, check with your county ag commissioner or extension agent, and with any local beekeeping clubs, or a web search for live bee removal and your city. It’s also sometimes possible to trap bees out of a cavity, as described at this link.
Killing Honey Bees
A lot of insecticides can be used to kill bees, the principal problem is getting the material to the bees inside a cavity, with multiple wax combs forming further barriers to insecticide application. Sometimes holes are drilled in the wall to inject insecticide, in certain cases it can be applied through the entrance that the bees use.
Note that the use of insecticide will render any honey in the honey bee colony inedible, and dangerous to other bees that might collect it in the trash, so dispose of it inside sealed trash bags.
Removing the Honey Bee Nest
When the job ends with killing the bees, you have up to 10 pounds of dead bees, several more pounds of developing bee larvae, wax combs and up to 100 or so pounds of honey still inside.
The rotting bees can smell pretty bad, and, with no bees to protect them, the combs may melt or fall. When this happens, honey will leak out and can seep out through your wallpaper and baseboards, and even between stories in a house.
This is not good, and to avoid it you need to remove the dead bees and the nest. This nearly always involves opening up the cavity (i.e. removing siding or wallboard) scraping out the mess, and then repairing the wall. As you fear, this is costly and troublesome.
Filling the cavity
When you remove the nest, it’s important to keep in mindthat the smell of the old nest will remain indefinitely and make the cavity particularly attractive to future swarms of bees, so the problem can recur.
To avoid this, it is important make it so there’s no longer a cavity there for bees to move into. The easiest way to do this is typically to fill up the space (all the space you or the bees can get to) with fiberglass insulation. I prefer this because it typically won’t settle, as some other materials do.
Then, although scout bees may be attracted by the smell of the old nest, when they crawl inside they’ll not find a cavity of usable size, so they won’t bring the rest of the swarm.
Plugging actual or potential Honey Bee entrances
Even if you’ve filled the cavity, it’s a good idea to plug up or screen over any holes or cracks that lead into the cavity.
When screening, use mesh with less than 1/4 inch openings (e.g. 1/8 hardware cloth or window screen). Remember, even if the bees were using just one entrance, other entrances may exist; you should search for them and close them off
Do I’ve to do all that?
If you know for sure that a colony has moved into a cavity within the last 2 days, it’ll not have built much comb or stored much honey. In this situation you may get away with just killing the bees, hoping they don’t smell too much, and carefully closing off all entrances to the cavity.
It is always better to do the full job above, despite the expenditure in time and money. If the bees have been in place more than a week you’re asking for trouble not to open the cavity to remove them. On occasion you’ll get away with it, but it can make a bad problem a lot worse when you don’t.
What if I can’t open the cavity?
At times the bees are nesting inside a masonry wall, or other location that can’t be opened. It could be possible to trap bees out, as described at this link. Or, the best you could be able to do is kill the bees, perhaps fill the cavity with pourable insulation, block entrances very thoroughly, and cross your fingers.
As the above description suggests, it’s troublesome and costly to have bees removed from a nest in your house. It is far better to prevent them nesting there in the first place.
This is where “bee proofing” comes in. If bees cannot find a hole leading to a suitable cavity, they will not move in. You can get there first, and scrutinize your property for potential bee nests. Look for holes or cracks in the walls, soffits, etc that might lead to cavities in the walls or attic. Caulk up the holes, or screen them over.
Additionally, look for other potential nesting sites, anything with a fairly small hole leading to a cavity – examples include upside down flower pots, old water heaters, electrical boxes, barbeques, etc. If the cavity is removed (take it to the dump) made broad open (turn the flower pot over) or inaccessible (plug the holes leading to the cavity), it’ll no longer attract nesting bees.
Dealing With Honey Bee Swarms
Because swarms are relatively docile, and since they’re ordinarily completely exposed, gathering them or destroying them is easier than with established colonies.
Aside from that, when you do nothing, a swarm will ordinarily leave with a day or so. The problem is, when they leave, it is to establish a nest in a cavity somewhere, where they’re likely to be a greater problem. That “somewhere” might not be on property that is your responsibility, but it could be.
There was a time when it was fairly easy to find a beekeeper who was interested in gathering swarms when he or she got the chance, at times for no charge. These days, that it rare, because there are fewer beekeepers, because liability concerns have increased, and because swarms are less valuable since they may be Africanized and will require a change to queen to be useful to a beekeeper.
A swarm may be gathered by knocking it into a box, ideally a beehive with combs, waiting for all the bees to go inside (usually until nightfall) and then taking the new hive to a permanent location. For a beekeeper this isn’t so hard to do, since they are accustomed to working with bees, and have a veil handy to protect them from the possibility of stings (not too likely, but it does happen).
For the non-specialist it’s still possible, but more daunting. When the swarm is close to the ground it’s of course easier to remove than if it requires climbing a ladder (or a tree!)
Swarms can be killed fairly easily with insecticides, or with surfactant (detergent) solutions. In California, the law requires that a surfactant be registered for this use as an insecticide, and no registered product is available to the public (Mpede insecticidal soap is used by vector control and pest control operators).
Insecticides are more likely to annoy and disrupt the bees. For most individuals , the best course is hire a professonial pest control person to remove the swarm of bees.