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We are always searching for magical ways to control household and garden pests. At the moment, the popular cure for unwanted stinging insects seems to be vinegar sprayed from a bottle. But can you actually kill bees with household vinegar?
I wasn’t aware that trying to kill bees with vinegar was even a thing until someone asked me if it works. My off-the-cuff answer was “no way.” But then (just to be sure) I spent hours reading dozens of websites touting the virtues of household vinegar. Apparently, it is the answer to all your bee and wasp problems. After I read all these incredible claims, my answer was still “no way.” None of them make scientific sense.
How vinegar is supposed to kill bees and wasps
According to these accounts, the pH of vinegar will kill stinging insects instantly. But wait. Household vinegar is a solution of 5% acetic acid (by volume) in water. Its pH varies slightly with the type of vinegar. For example, 5% apple cider vinegar is considered mildly acetic with a pH of 2-3. White vinegar at 5% has a pH of approximately 2.5.
According to the National Honey Board, the acidity of honey ranges from a pH of about 3.4 to about 6.1, with an average of 3.9. So a solution of 5% acetic acid by volume is more acidic than the most acidic honey.
But here’s the thing: nearly all the “recipes” I’ve read say to dilute the household vinegar in water at a rate of 1 teaspoon per quart of water or 1 tablespoon per gallon of water before you put it in your sprayer. That will further reduce the acidity, making it almost useless for killing anything as tough as a bee or a wasp.
Bees are accustomed to acidic conditions
I suppose I could calculate the pH of such a solution, but it’s not simple. To start, the pH scale is logarithmic, meaning a pH of 4 is ten times more acidic than a pH of 5 and 100 times more acidic than a pH of 6. In addition, you would have to know the pH of the dilution water and whether it contains anything that might affect the total pH, such as calcium or magnesium.
But even without a calculation, we know your solution won’t be more acidic than the vinegar that went into it. Most likely, it will be quite a bit less.
According to the Material Safety Data Sheet, the pH of FormicPro (for varroa mite control) is 2, more acidic than your average household vinegar. But we trust that it won’t kill our bees when we put it in the hive. One article in Bee Culture suggested the pH of oxalic acid is down around 1, although it didn’t say at what concentration or in what format. Still, how many beekeepers successfully use oxalic acid in their bee hives? Most?
My point is that bees, especially honey bees, are accustomed to living around and eating very acidic things. So a solution of 1 tablespoon of 5% acetic acid in a gallon of water for killing bees makes no sense. Many beekeepers put more vinegar than that in their sugar syrups to prevent mold and the bees don’t give a wit.
Wasps are not repelled by the scent of vinegar
Some articles say the smell of vinegar repels wasps so they leave and never come back. They’re kidding, right? In truth, the smell of vinegar is a reliable wasp attractant. It’s the vinegar scent of rotting fruit that attracts wasps in droves to apple and pear orchards in the fall.
Vinegar is also used in some wasp traps to lure them into the catch jar. Since the wasps adore the scent of vinegar, you can trap them easily. In short, you can use vinegar to attract wasps and then kill them, but the scent of vinegar itself isn’t going to repel or kill them.
So how are bees being killed if not by acid?
Further reading explained how some of these methods “work.” Some articles instructed the user to stamp on the bees when they hit the ground. In this case, I assume the sprayed solution wet the bees’ wings enough that they couldn’t fly, so they fell to the ground. Then someone stepped on them. The lethal agent in this case was the bottom of a shoe, not the vinegar. If the bee wasn’t smushed, it would be able to fly again once its wings dried.
In other cases, the recipe contained “a few drops of dish soap.” Now dish soap liberally sprayed on bees will kill them. That’s because soapy water acts as a surfactant that destroys the surface tension of water and weakens the protective coating on an insect’s exoskeleton. Soapy water will kill bees and wasps quickly and efficiently: no vinegar is needed.
Not all vinegar is created equal
I should mention that you can also buy horticultural vinegar which is around 20% acetic acid by volume. Like oxalic acid, this is toxic stuff and the user should wear a respirator. Might it kill bees? Well, it depends on how much you dilute it. But in any case, why not just use a few drops of dish soap in a bottle of water and not bother with hazardous products that may or may not work?
Think about why you need to kill bees
I can imagine a few instances where a hive of bees might need to be killed. Perhaps a colony is excessively nasty, diseased, or built a home that is interfering with machinery or air ducts. Perhaps normal removal methods have been unsuccessful for some reason. But killing bees just because it’s more convenient than dealing with them is sad.
One person whose blog I read was going to boil a cauldron of apple cider vinegar in his backyard. He believed the vapor would kill all the native mining bees in his lawn by infiltrating their nesting holes deep in the ground. It’s sad that he thinks it’s necessary, but it’s also kind of funny. The bees, nestled in their underground chambers, were probably laughing themselves silly as the guy toiled away, stirring and chanting on a blistery summer afternoon as his vapor wafts away on a light breeze.
If you have a bee problem, call a beekeeper. He or she may be able to help, regardless of the type of bee. These days, more and more beekeepers are aware and sensitive to other bee species and may know where you can find some help. Ask before you kill and you will be doing the planet a favor and looking a lot less silly.
Honey Bee Suite