Key Points:

• Sugar shakes are not non-lethal to bees
• Sugar shake results are highly variable due to environmental conditions and user error
• Sugar shake results may not reflect when treatment is required

The sugar shake method for Varroa monitoring is often marketed as non-lethal to bees. This is one common reason that beekeepers choose sugar shakes rather than alcohol or soapy water washes. But do sugar shakes really spare the bees?

A recent study by Bruckner et al. (2025) at Auburn University endeavoured to answer this question. The researchers marked adult worker bees and put them into three different groups:

1. powdered sugar and shaken
2. powdered sugar and not shaken, and
3. no powdered sugar or shaking (negative control).

After the various sugar and shaking treatments, the researchers reintroduced those bees to full-sized colonies and checked five days later to see how many marked bees they could recover.

Bees that underwent a sugar shake were less likely to be recovered five days later than the other two groups (table 1), indicating that the sugar shaken bees died prematurely. NSW Bee Biosecurity Officer, Sam Giggins, found similar results in a small trial he conducted in his own apiary.

Interestingly, Bruckner et al. (2025) found that sugar coating didn’t have an impact on the number of bees they recovered, but sugar coating AND shaking did. This suggests that the cause of death is physical shaking. They didn’t shake bees without sugar, so it is uncertain whether there would be a difference in recovery if bees were shaken with or without it.

Table 1. The percent of marked bees recovered five days after sugar/shake treatment and reintroduction to colonies. Table based on results by Bruckner et al. (2025).

Sugar Shake Efficacy

Bruckner et al. (2025) also looked at sugar shake efficacy. They found that sugar shaking was highly variable with 67-100% mite recovery compared to alcohol washing.

The trouble with sugar shakes is that their efficacy depends on the environment. If it’s humid or there’s a good nectar flow on, powdered sugar is more likely to clump which decreases its ability to coat the bees and dislodge mites. How hard the beekeeper shakes also influences results. It’s possible that fewer bees die in the process if the beekeeper shakes them gently, but fewer mites are dislodged. This causes the beekeeper to underestimate their mite loads, putting the health of entire colonies at risk.

Anecdotally, the National Varroa Mite Management Program team found that our if we shook vigorously and repeated steps twice on the same bees. However, this prolongs the process for the bees and the beekeeper when a quick mite wash would suffice.

In summary, the assumption that honey bee workers survive a powdered sugar shake is false.

Bruckner et al. (2025) said it well: “In summary, the assumption that honey bee workers survive a powdered sugar shake is false.” They concluded their paper recommending that beekeepers use the alcohol wash method to monitor for mites.