Varroa mites (or varroa destructor) are an external parasite that attacks honey bees. This mite attaches itself to the bee and feeds off its blood (similar to a tick) and can cause weakness and deformities in the bee population. A significant mite infestation can cause an entire colony to weaken and die if not treated.
It’s pretty likely that there are mites in your hive. The questions are how many and to what extent are these mites affecting the colony? There are chemicals, of course, to treat these pests, but we don’t like to apply such things to our hives. Researchers are trying to breed ultra-hygenic bees (who consistently clean the mites off of themselves), but in the meantime, varroa continues to be something beekeepers have to contend with. Recently, a researcher at Michigan State University (Dr. Huang) authored a paper in ABJ suggesting that the mites are able to adapt their odor and basically make themselves smell like the bees. This might explain why the bees are unable to detect them on their own.
We’ve always kind of ignored the likelihood of mites in our hives, but our winter loss rate has forced us to consider every variable. This year we vowed to make some changes in terms of mite control. The first step is determining if we even have a significant mite infestation. For our first attempt, we tried out one version of the powdered sugar test. There are two ways to do this: one way is to apply the sugar to the hive itself and the other method is to take a sampling of bees and perform the test in a mason jar (directions HERE). We decided to try method #1 first.
How this works is you sprinkle some powdered sugar into the hive (on brood frames only, try to avoid honey frames) and then put a cooking spray-coated piece of card stock on the bottom board underneath. The powdered sugar does two things: it prevents the mites from attaching to the bees because they are too slippery and it causes the bees to groom themselves and inadvertently remove mites. These mites then fall to the bottom board where they stick to the cooking spray. We can then get an idea of how many mites are in the hive based on how many collect on the bottom board. I’ve read some websites where people were able to see evidence of mites within an hour. Some beekeepers use this as a treatment for mites, rather than simply a test, as it forces the bees to clean the mites off every time you treat.
To do this, we used a box with a screened bottom like a sifter, basically. We placed this on the box we wanted to treat….
Then sprinkled the powdered sugar over…
We then applied cooking spray to a piece of card stock…
laid it on the bottom board and slid it back into place…
I wish I could have gotten some better pictures. After doing this we had white, sugar-coated bees flying around. They looked like ghost bees! We imagined neighbors sitting on their decks watching the bees working their flowers and then – all of a sudden – thinking, “What the heck is this WHITE bee!?” (we have overactive imaginations)
The result?? Well, pretty anticlimactic. We didn’t see much evidence of mites. This should make us happy, but instead it made us question the method. We’ll try it again in a few weeks and maybe try the mason jar method, just as a comparison.
HERE is a great overview from Scientific Beekeeping of this method and some results as to whether or not powdered sugar actually treats mites.
More reading material on this method HERE as well.