Download PDF of experimental protocol
Varroa mites (Varroa destructor) are the most noxious parasite of honey bee colonies, and as such they have been the bane of beekeepers for the last 3 decades. There are many different weapons in the beekeeper’s arsenal to control varroa, ranging from genetic stocks, mechanical techniques (e.g., screened bottom boards, drone-brood removal, sugar dusting), “softer” biopesticides (e.g., ApiLife VAR®, formic acid), to the “harder” synthetic acaricides (e.g., Apivar®, Apistan®, Checkmite+®). More information about mites and treatment options can be found in our Beekeeping Note 2.03, as well as the ‘Advanced’ course on Varroa Integrated Pest Management (BEES 2.02.04) on the online Beekeeper Education & Engagement System.
As part of any good program for sustainable integrated pest control, beekeepers need to regularly monitor the levels of mites in their hives. Moreover, it is important to measure mite levels before and after any intervening action (=treatment) to ensure that the approach is effective. The two most common methods for measuring varroa are the ‘sticky board’ and ‘sugar shake’ methods (see instructional videos below).
Objective: measure the levels of varroa mites in a pair of colonies before and after treatment to gauge the relative efficacy of different mite-control strategies.
Materials and Methods
You will need at least two colonies to participate. More colonies are welcomed, but they need to be tested in pairs. For each colony pair, you will need to keep one as a ‘negative control’ where you don’t use any measures for mite control (i.e., leave it alone to see how high the mite levels would go if you do nothing). For the second hive in a pair, you will want to implement whichever control measure you wish to compare. Otherwise, both hives should be as similar to each other as possible, transferring frames between them to equalize adult population and brood if necessary (but only prior to the start of the experiment).
Then, before taking any action for mites in the ‘treatment’ hive, you will need to monitor both hives in each pair for varroa using two standard techniques. First, measure the entire ‘mite load’ of each colony by inserting separate sticky boards into each hive for 72 hours. Second, after removing each sticky board, measure the ‘mite intensity’ of both colonies using separate sugar shakes and calculating the number of mites per 100 adult bees.
These two mite measurements should be taken twice before varroa treatment (once in July, and once in early August), then twice again after varroa treatment (once in late August and once in September). These measurements will therefore gauge how effective a given treatment has been for reducing the number of mites in your colony.
We will also need some additional information about your beehives—like their general location, the basic equipment, and the genetic stock—since each of these factors may have an influence on mite levels. Note that no personal information is requested or needed to make accurate inferences.
After you have all of the mite counts, send them into us and we’ll analyze the data. We can then parse the different mite treatments to compare the average levels of mite control among those using various control strategies. In doing so, we hope to be able to provide empirical evidence as to which tactics work best.
Submitting your results
Please enter your data into the online form at:
Alternatively, please download the PDF form and send in your completed data sheet to the NC State Apiculture Program at:
Analysis and reporting
Mite levels usually increase over the summer, so it is likely that both measures of varroa will increase in the Control colony over the 4 measurement periods. For the Treatment colony, the post-treatment measures (late August) may be temporarily higher depending on the course of action—effective treatments may kill more mites resulting in higher mite drops. Compare the September mite levels to see how effective your control strategy is compared to doing nothing.
Keep posted to the Wolfpack’s Waggle and the Beekeeper Education & Engagement System (BEES) for details on our collective findings. Our goal will be to publish the results in a peer-reviewed scientific journal (e.g., the Journal of Apicultural Research) or beekeeping periodical (e.g., American Bee Journal), depending on the scale, scope, and quality of the data. The more beekeeper participants, the better our data, and the more likely it will be published!