Sugar roll test for Varroa mites
The best way to test your colony for mites is to use the Powdered Sugar Roll Test developed at the University of Minnesota. It is important to note that the Powdered Sugar Roll Test is not the same as dusting for mites and then counting bodies on the bottom board. This test is more involved and more accurate.
Click the link below to see a nice visual presentation of the steps. The part that people sometimes miss, right at the end, says this:“If you know how many bees were in your sample, you can estimate the number of mites per 100 bees. If there is brood in the colony when you sample, you should double this number to factor in the amount of mites in worker brood. For example, if there are 5 mites/100 bees, the total infestation is probably 10 mites/100 bees. If your colony has over 10-12 mites/100 bees, you should consider treatment.”