Glossary
A non-lethal method for estimating varroa mite infestation levels in a honey bee colony. A sample of approximately 300 bees is placed in a jar with powdered sugar, shaken to dislodge mites, and the mites are counted after sifting through a mesh lid.
The sugar shake test is one of the two standard methods for monitoring varroa mite levels (the other being the alcohol wash). It is slightly less accurate than the alcohol wash but has the significant advantage of being non-lethal to the sampled bees.
Equipment needed: a wide-mouth mason jar fitted with a #8 hardware cloth lid, powdered sugar, a white tray or bowl, a measuring cup or scoop that holds approximately 300 bees (about 1/2 cup), and water.
Collection: Open the colony and locate a brood frame. Shake or scoop approximately 300 bees (half a cup) into the jar. Avoid the queen. Add 2 tablespoons of powdered sugar through the mesh lid. Cap and roll the jar gently for 1 to 2 minutes, coating all bees thoroughly. The powdered sugar disrupts the mites' grip on the bees.
Counting: Invert the jar over the white tray and shake vigorously for 1 minute. The mites (and sugar) fall through the mesh onto the tray. You may need to add a small amount of water to dissolve the sugar and make the dark mites visible. Count all mites on the tray. Return the sugar-coated bees to the hive; they will clean themselves within minutes.
Divide the mite count by the approximate number of bees (300 for a half-cup sample) and multiply by 100 to get mites per hundred bees. Treatment thresholds: 0 to 1 mites per 100 bees is low and acceptable. 2 to 3 is approaching the treatment threshold. Above 3 mites per 100 bees, treatment is recommended before the infestation escalates to colony-threatening levels.
The sugar shake test detects approximately 50 to 75% of the mites actually present on the sampled bees (the alcohol wash detects closer to 90%). It is useful for monitoring trends over time and identifying when mite levels are approaching treatment thresholds, even though it slightly underestimates the true infestation.
It is safest to locate the queen and set her frame aside before sampling to avoid accidentally including her in the jar. However, the odds of scooping up the one queen among 30,000 to 60,000 workers are very low. Many beekeepers sample without finding the queen first and have never had an issue.
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