Heat Treatment for Varroa Destructor Mites

This is an ongoing experiment to try and see if it’s possible and realistic to treat for mites using carefully controlled heat with no chemicals.

In the photo to the right, this was during the actual 1st attempt at treating a single-deep hive using forced heat.

Before treatment, an alcohol wash showed 2 mites out of 300 bees. Not terrible, but we need a baseline.

The top cover and feeder are removed from the hive and the heat treatment box is placed on top. A screen on the bottom of the box will prevent any bees from climbing into the treatment box. A thermostat, fans, and heating element are mounted inside the box, which is ran by the controls mounted on the outside of the box. A PID controller monitors the heat and runs the heating element accordingly with the ideal temperature set at 108°F. Fans force the hot air up into an exhaust hose which runs down and into an adapter that fits into the front entrance of the hive. Because forager bees are out during the day, blocking the main entrance proves risky, but I did restrict the open down to a very small hole using some extra pieces of foam board.

During the 2 hour duration of the heat treatment, many of the bees came outside and bearded on the front corner of the hive. So right away, I figured I wasn’t getting a good treatment on all of these bees… but the brood inside should be getting the treatment as the heat soaks into the brood. The idea is for the carefully controlled heat to saturate and kill the mites in with the brood, but not injure the brood themselves.

After the treatment cycle, another mite wash was performed a couple of weeks later. That one only saw 1 mite out of 300 bees. Better… but not a perfect 0. Granted since so many bees clustered on the front of the hive during the treatment, that may have played a big factor.