Raising honey bees is fun and fascinating, but it’s important to remember that they are livestock, and you’ll be responsible for their health and overall care.
Varroa mites are a problem that all beekeepers will need to deal with. Fortunately, there are many different mite treatments available.
One very popular and effective method is an oxalic acid bee treatment. There are a few ways to use oxalic acid, and what you choose depends on your personal preferences.
Make sure you’re prepared for mites and learn all about how to do an oxalic acid bee treatment below.
What Is Oxalic Acid?
Oxalic acid is a natural compound that occurs in many plants and even honey. It acts as a natural repellant.
Oxalic acid is made up of four oxygen, two hydrogen, and two carbon molecules.
For beekeeping, oxalic acid comes in the form of a colorless solid powder that dissolves in water. It can also be used in cleaning applications, so it’s important to use it correctly to avoid harming your bees.
It’s a relatively new approved mite treatment and is inexpensive. This makes it a great option for many beekeepers.
Oxalic acid for use in beekeeping is regulated by the EPA, and label instructions must be followed carefully.
How Oxalic Acid Bee Treatments Work
Oxalic acid bee treatments are very effective against varroa mites, although we don’t completely understand how they work.
It is believed that the liquid or vaporized acid enters the mites’ bloodstream through their feet when they come in contact with liquid or vaporized oxalic acid.
Oxalic acid bee treatments don’t disturb or harm the bees as long as they are used correctly. However, these treatments only work on “phoretic” mites or mites that are crawling on frames or bees and not enclosed in capped brood cells. Oxalic acid is not able to penetrate the wax cappings or the larvae inside.
Using Oxalic Acid Bee Treatment
When used correctly, an oxalic acid bee treatment can wipe out 90 percent of mites or more.
There are different methods you can use to treat with oxalic acid depending on how many hives you have and how many treatments you want to apply. You may also feel more comfortable with one method over another.
Timing is also important for oxalic acid treatments and will help determine how you can use them most effectively.
When to Use Oxalic Bee Treatment
An oxalic acid bee treatment works best when there is little to no capped brood in the hive. This is because the acid vapors can’t reach mites hidden inside capped brood, where many of the mites may be hiding out.
The best time to use an oxalic acid bee treatment is late fall or into winter. You don’t need to worry too much about temperatures, especially if you use the vaporization method, so it’s perfect for one last treatment before winter sets in.
If you decide to treat with oxalic vapor when brood is present, you will need to apply it more than once to catch bees that had been hiding in capped brood cells.
When Not to Use Oxalic Bee Treatment
As previously discussed, this treatment will only work on mites that are on bees or crawling around the hive. If you have a lot of capped brood, it may be better to use a different type of treatment.
Overuse of oxalic acid bee treatments can eventually create mite resistance. Once a mite infestation becomes resistant to a treatment method, you should stop using it, as it will no longer work well or at all. Because of this, it’s best to use oxalic acid in conjunction with other mite treatments throughout the year to avoid resistance.
Don’t treat with oxalic acid without testing for mites or if your mite load is below the threshold of 3 mites per 100 bees. Unnecessary applications can also contribute to mite resistance. There are other alternative treatments you can use in those situations.
If temperatures are below 37 degrees, it is too cold for oxalic acid. It should also be avoided in the height of summer in hot temperatures.
While oxalic acid bee treatments are generally safe, it’s still important to take a few precautions to protect yourself.
You should always read labels carefully and follow the instructions exactly. Prepare all your materials before you get started and plan out the process first so you can perform your treatment smoothly.
Be sure to use a respirator, especially if you are using the vaporization method. Breathing in the fumes can be hazardous to your health.
Do not touch the oxalic acid on your bare skin. It is a known irritant and can be very toxic when not used correctly. Always wear hand protection when using oxalic acid.
Finally, avoid overusing oxalic acid bee treatments. For best results, rotate through different treatment types.
Different Application Methods for Oxalic Acid Bee Treatments
There are a few different ways to use oxalic acid to safely and effectively treat your bees for mites.
You can use a liquid dribble technique, invest in a vapor wand to use the sublimation method, or you can mist your bees.
The method you choose will depend on how many hives you have in your apiary, what your budget is, and also what seems the most accessible and doable to you.
For any treatment method, you will need to start with oxalic acid. Since the acid can’t get to mites in capped brood, it’s best to use both during a period where there is a break in brood.
First up is the dribble method for oxalic acid bee treatments. This works well for a single treatment or if you only have a few hives. It’s more budget-friendly as well, so it may appeal to new or small-scale beekeepers. It’s a bit more involved and hands-on.
The dribble method requires that you open up the hive to apply it, so it can only be used when it’s warm enough outside.
Here’s the equipment you’ll need to use the dribble method for an oxalic acid bee treatment:
- A dedicated container that can be fully sealed (nothing you plan to store food or anything else in)
- A scale
- A syringe
- A wood or plastic stirrer
- Protective gear (this can be your beekeeping suit, veil, and gloves, but you may also want to use a respirator for safety)
- Hot water
This recipe will make enough to treat five hives. Start by dissolving 8.75 grams of oxalic acid in 150 grams of hot water. Stir to dissolve, and do not shake the mixture.
Add 3/4 cup of sugar and continue stirring until the sugar is fully dissolved. Make sure to clearly label your container.
Once you’re ready to begin your oxalic acid bee treatment, bring your mixture and other materials, plus a bottle of fresh water, out to your hives. The water is a safety measure in case you accidentally get any of the acid on your skin.
Draw 50 ccs of the acid mixture into your syringe. Do not use more than this in a single hive, or you risk harming your bees.
Start in the lower hive body if you have more than one. Dribble no more than five ccs on the bees in between each frame as well as on the top of the frames. Continue with the top box until you don’t see any more bees or you’ve used the entire syringe.
Close up the hive, and you’re all set!
Vaporization or Sublimation Method
For the vaporization method of an oxalic acid bee treatment, a special wand will vaporize or sublimate the acid powder to essentially fumigate the hive. Sublimation is when a solid is converted directly into a gas, skipping the liquid phase.
This is a good option for larger apiaries and doesn’t require opening the hive, so it’s a great option for colder weather.
It’s much simpler to prepare, but you’ll need a vapor wand. It’s also faster and may be less harsh on the bees.
For a vapor oxalic acid bee treatment, it’s especially important that you wear a respirator so you can avoid inhaling the fumes.
You will need:
- A vaporizing wand
- Battery to power the vaporizer
- A respirator
- Paper towel to plug entrances
- A timer
- A bucket of water
Start by measuring the acid powder into the vapor wand, adding 1/4 teaspoon per box per hive.
Use the paper towel to plug up any entrances up toward the top of the hive, and remove your entrance reducer if you have one.
Use your smoker and puff into the bottom entrance to encourage the bees to move up and away from the entrance so they won’t come into contact with the hot wand.
Carefully slide the wand in through the bottom entrance, watching to make sure you avoid any comb that might be hanging down. Most wands will have a marking on them to let you know how far to insert the wand. Plug up the rest of the entrance around the wand with a paper towel.
Keep the wand level and turn the vaporizer on, then start a timer for 2 minutes and 30 seconds. You may see some of the vapor leaking out, and that’s okay as long as there aren’t any large gaps for it to escape from.
Once your timer is up, turn the vaporizer off and set another timer for 2 minutes. Leave the wand still in the hive.
After 2 minutes, remove the wand and reseal the entrance. Start a timer for 10 minutes and dunk the want into the bucket of water to cool it.
Once your timer goes off, remove all paper towels and allow the hive to ventilate for 10 to 15 minutes. Then you can fully close the hive back up with your entrance reducer or any other pieces you removed.
If you want to treat multiple hives, you can do them simultaneously as long as you’re able to have multiple timers going at once. For your first treatment, just do one hive at a time until you feel more comfortable with the process.
Oxalic Acid Mist
Misting works best as an oxalic acid bee treatment for new packages or swarms that have not yet been put into a hive. It should not be used as a regular hive treatment.
Mix up some 1:1 sugar syrup and give the bees a spray, so they keep busy and full on sugar water.
Then mix a small amount of acid into the sugar water and mist them again. This is not the best method to use in general, but it can be an insurance policy on bees that are new to you.
After you have completed an oxalic acid bee treatment, you need to make sure it worked.
Always test your colony before and after you treat. This will give you essential information that will inform your next steps and also influence how you decide to treat for mites in the future.
If you find that your oxalic acid bee treatment did not work, you may want to consider trying something else instead of repeating it. This will depend on what time of year it is as not all mite treatments can be done in certain temperatures. Repeating an oxalic treatment is okay if you’re using it when you also have capped brood present.
If you still lose your bees to mites, don’t be discouraged. It can be a frustrating problem to resolve, and almost every beekeeper in the world knows how you feel. If you’re struggling to figure out a good treatment routine, check with people in your area to see what works best for them.
Keep Your Bees Healthy With Oxalic Acid
Oxalic acid bee treatments might sound intimidating, but they’re actually pretty simple and a great way to keep mites in check.
It’s so important to treat your bees for mites, and oxalic acid is one of many options for beekeepers to use. You can try each method or stick with the one you’re most comfortable with.
Mite treatments are just one aspect of beekeeping, so read up on everything you need to know to successfully raise honey bees!
- About the Author
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Hope Schwartz-Leeper is an avid reader, writer, and lover of all things nature with degrees in English and Philosophy.
Born and raised in the Northeast, Hope has always had an affinity for spending time outside. Growing up and attending college in New York, then living on Cape Cod and finally settling in Rhode Island has given her plenty of experience with the climate and environment of these areas.
She loves growing her own food and plants and is always trying to grow something new. She’s hoping her apple trees will one day bear fruit, but for now she’s excited about anything that comes from the garden.