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How to Test Your Hive for Varroa Mites

Feb 05, 2021

A varroa mite test is a test the beekeeper conducts to see what the percentage of mites to bees are in the hive. 

The beekeeper takes a half of a cup of cup (yes, with a measuring cup like you're baking a cake) and combining them with rubbing alcohol. This, unfortunately, kills the bees, but also causes the mites to fall off of the bees. The beekeeper, then, counts the amount of mites in their sampling. 

A half a cup of bees is approximately 300 bees. You then know how many mites per 300 bees you have. This gives you an idea of the overall percentage of mites in the entire hive.

 


1/2 cup of bees is approximately 300 bees.


 

If you're horrified at the thought of killing 300 bees, please remember that this is to potentially save a hive from an infestation that will likely cause your hive to collapse over winter (or possibly even sooner). I don't think there is a single worker bee who wouldn't die at a moment's notice for the sake of her. They do, after all, die when they sting. There are also hundreds of bees in a full size hive that are dying every day. This is because the queen can lay up to 2,000 eggs a day and these eggs hatch into an adult bee that will live just 4-8 weeks in the spring and summer.

 

Why Test

If there's nothing else I hope you do when you have your bees, it is to test for mites monthly. If you take my beekeeping class, you may even be tired of hearing me talk about mite tests. The reason why I so strongly encourage testing for mites is because a varroa mite infestation can lead to a lot of problems in the hive. Students say that their bees are cranky, aggressive, not bringing in a lot of honey, absconding (leaving the hive ), and not surviving the winter. All of these problems can be caused by a mite infestation!

If you choose to keep your bees treatment free, testing for mites will tell you which hives are not dealing with mites well and should be combined with a stronger hive. There's no point in preparing 5 hives for the winter if 2 have a mite level so high that they stand no chance of survival. A mite test will also tell you which hives are naturally dealing with mites and should be split.   

 

How to Make a Mite Test

This test is easy to make with items you can buy at the local store and takes just a few minutes to conduct. 

Watch the video below and to learn how to test for mites.

If you'd like to skip to a specific part, here's the time stamps:

  • How to make a mite test, 3:11
  • Testing for mites, 9:04
  • What the results mean, 23:52

 

 


Want more pest management help?

This video is a lesson from our online beekeeping class, Beekeeping for Beginners. In this class we show you how to deal with pests so your hive is healthy! Learn more about Beekeeping for Beginners.


 

What Your Mite Test Results Mean

This is where things can get confusing, but they don't have to be. The easiest way to understand it all is to check out our video where I walk you through what I do (starts at 23:52 in the video above), but I also have a basic explanation below.

 0-1 Great!

Your hives have very few mites. No need to treat. Keep an eye on this hive, if they consistently have a mite level of 0-1 for a few months, this is a hive to breed from!

2-6 OK, but keep an eye on them

If it is early spring, you may want to treat before honey starts coming in. Many treatments stay in the hive for about 6 weeks, so if you put a treatment into your hive, do it within 6 weeks of the honey season starting. If you're not sure when this is, you can talk to beekeepers in your area, or just think about when you start to see a lot of flowers blooming. This is usually late Spring. 

If it is summer or when the bees are bringing in a lot of honey, and you have honey supers on your hive, do not treat. Your bees will be just fine until you harvest the honey.

If it is late Summer, treat once the honey supers are off the hive and freeze capped drone comb (where a lot of the mites are laying their eggs) to decrease levels as much as possible. If you use foundation, make sure you put 1-2 frames of drone foundation in each brood box.

If it is Fall, treat just before you are ready to close up the hive for the winter. 

7-12 Not good

When your test has a mite level of between 7-12, it's not good for the hive. This is a high mite level and it is recommended that you put a treatment in. There is some wwiggle room here. If it's late summer and you'll be harvesting in a week or two, it should be fine to wait and treat. If it's June and you have a mite level of 7, the mite level will only get worse as summer goes on and you might as well treat sooner than later. 

You really want to avoid treating when the bees are bringing in a lot of honey. That's why a Spring treatment to prevent trouble in the summer is best. 

12+ Treat or merge hive ASAP 

At this point the hive will begin to get run down with viruses and is struggling. You should put in a treatment even if it is summer and they are bringing in honey. Remember to remove the honey before putting the treatment in. 

 45+ Bees usually abscond

Absconding is when the entire hive takes off, leaving all the food and brood (baby bees) behind. When bees do this, they are leaving a lot of the mites behind because over 90% of the mites in a hive are in the capped brood. However, once the bees are at the point that their mite levels are so high, they usually also have many viruses (brought by the mites) and are so weak that they cannot rebuild in time to survive winter.

 

 varroa mite on bee larvae

 

In Conclusion 

Mite tests are easy to make and take just a few minutes to conduct. 

Knowing your mite levels can help you prevent high amounts of viruses and help you troubleshoot problems in your hive. If a hive is struggling, the first thing the beekeeper should do is a mite test to see if mites are the culprit!

When analyzing your mite test results, keep in mind the time of year. It's best to be proactive in the early spring, later summer and fall, but in the summer (or whenever your bees are actively bringing in honey) is when you can allow a mite count to get a little higher. 

 

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