Sugar dusting is a labor intensive method, using a benign substance, to treat a beehive for varroa mites. Treatments can be applied when most other mite treatments can’t.
A varroa blaster is a simple, cheap as in free device, used to sugar dust a beehive.
Sugar dusting is an effective varroa mite treatment. Confectioner sugar dusting has some unusual benefits:
- ideal top bar or organic hive treatment
- bees and brood aren’t affected
- environmentally benign
- safe and easily stored
- readily available
- kills mites without stunning them
- can be applied during a honey flow
There are drawbacks as well:
- labor intensive
- very invasive
- proper timing is essential
- mite biology must be understood
- can’t treat clustered bees
- hives must be opened
Interested? Let’s build a varroa blaster. And it will take less time to build one than it takes to read about it.
- a small drill bit or a frame nail
- an empty, plastic juice, soda or salsa bottle
- some nylon stocking material large enough to cover the bottle’s mouth and overlap the screw on cap’s threads
- Remove the plastic lid
- Drill small holes in it. Or use a heated frame nail to melt them in the lid
- Fill the bottle 1/3 full with confectioners sugar
- Place the nylon material over the bottle’s mouth
- Screw the lid on, securing the nylon material in place with the lid
That’s a varroa blaster. What could be simpler than that?
Produce a fine, smoke like puff by squeezing the varroa blaster.
- shake the blaster
- rotate it horizontally
- and squeeze it vigorously
Sugar smoke should come out, not globs. The globs won’t hurt the bees or the mites. If you’ve got globs, tip it up and try again. If it’s still launching globs:
- the holes are too large
- the nylon material is too coarse
- or there is too much sugar inside the blaster
When the nylon material gets plugged, blasting takes more effort.
- tip the blaster upright
- then rap it on something solid knocking sugar clumps free from the nylon material
- occasionally, the nylon material must be removed and the clumps worked out
- replace it
- it’s as good as new
Dust a hive from the top down.
- remove the lid and two frames from one side
- set them aside
- then blast the exposed comb surfaces inside the hive
- slide a frame over
- and blast the untreated comb surfaces
- bees are lightly dusted
- they look like albino bees and not walking sugar globs
- repeat until all the frames are blasted
Each frame takes about three blasts. But this number varies depending on
- the blaster
- the quantity of bees,
- and the beekeeper’s strength
Hold the two frames removed from the hive, over the hive. Dust them. If a queen falls off, she falls back into the hive. Return the those frames to far side of the super.
Once a super is dusted
- set it aside
- and repeat the process for the boxes below
When all are dusted, set the hive together using lots of smoke. Smoking a hive is essential for a uniform treatment.
- smoke each super after it’s back on the hive
- bees should run from the smoke
- once the hive is together, vigorously smoke the entrance
Only phoretic mites are killed by blasting. The bees quickly consume the sugar. So, the mite’s exposure to it is brief. Proper timing is essential. The most effective treatment occurs when most mites are phoretic and when most bees are in the hive. Multiple treatments are timed to catch emerging mites before they are sealed up with the brood.
Most times, about two thirds of the mites are sealed up. If all phoretic mites are killed (33%) and every sealed mite reproduces(66%), it’s possible to have more mites, three weeks after treating, than before the treatment(132%)! So treatments must be done early and timed properly. If 66 mites increase to 132 mites it’s no big deal. But if 6600 sealed up mites increase to 13200 mites, the colony is doomed.
Mites quest about four days before returning to the brood. Worker brood is sealed for thirteen days. So four treatments spaced every four days should get most of them. But this math doesn’t account for mite immigration, reproductive failure, grooming and the invasive effects of closely timed varroa blasting. I think it takes about two days for a treated hives to recover from a treatment.
I’ve experimented with timing and settled on three treatments. One given every week.
Spot treatments are effective. Mites reproduce at different rates during the season. An observant beekeeper treats when signs show a mite increase. Mite fecal staining is a sign. Visible mites on bees or symptoms like deformed or milky wing virus call for an immediate spot treatment. In my climate, several windows of opportunity exist. Treating, then, decimates the mite population. I’m sure windows exist in most climates.
To determine the blasters effectiveness, I monitored the mite load. Nucs were used under various conditions and timings. In the process, I watched lots of mites. Here’s what I saw:
Sugar dust doesn’t affect open larva. Normally, the blast isn’t directed into the cells. I’ve dusted frames by blasting directly into open brood cells. The brood survived.
Mites drop rapidly for an hour after treatment. Significant mite fall continues another 24 hours. Then it decreases to almost nothing for several days. I think the extended sugar effects occurs when bees clean out empty cells containing more sugar. Dead mites are also removed from those empty cells.
Dusted mites are dead mites. They land on their back and can’t snap roll, righting themselves like an untreated mite does.
Treated mites are dead within hours. I’ve never seen a treated mite survive beyond 24 hours. Untreated mites easily quest away from the bees for five days.
Blaster treated mites can’t re-attach themselves to bees. A few stray bees got trapped between the screened bottom board and the mite tray. After a few days, these bees are covered with mites. I’ve never found a mite on a trapped bee in a blasted hive. Dusting should be effective without using screened bottom boards.
Confectioners sugar is great on donuts. But, it’s horrible in the lungs. Don’t breathe the stuff, no matter how sweet the smell. A cheap, paper respirator should give enough protection.
In 2008, The American Bee Journal ran a series of Powdered Sugar Dusting articles by Randy Oliver. His method of dusting bees is different than blasting. He brushes sugar, through a screen, on the top bars of frames beneath a hive’s cover. He’s a commercial beekeeper and doesn’t have time to blast a hive.
It’s a lot faster and easier than blasting. But I doubt it’s as effective.
Like Randy, I’ve used sugar dusting to do whole hive mite sampling. In the process, I’ve monitored hourly mite drop and tested sugar dusting’s efficiency. I’ve found that it’s not the amount of sugar, but it’s distribution that’s important.
Sugar dusting is most effective when it’s done when most of the bees in the hive, the sugar dust resembles smoke, and when the bees are run after the sugar is applied.
Without these three conditions, I found sugar dusting’s effectiveness to be problematic and inconsistent.
Sugar blasting mites doesn’t contaminate comb or poison bees. That’s why I used it to sample my small cell hives for mites. Natural mite fall doesn’t reflect mite levels when the bees cleanse the broodnest.
After those tests, my small cell hives tolerated mites and thrived without treatments. So, I haven’t used the blaster since then.
Later, I put small cell bees on clean, large cell hives. They couldn’t tolerate mites and required treatment to survive. I used oxalic acid and not powdered sugar. It was less disruptive. Required less labor. And could be done without opening the hives.
If several hives need treatment, I recommend dribbling oxalic acid.