Heat Treatment for Varroa: History and Advancements You Need to Know

We all felt it:

Last year was tough. Many of us lost record numbers of our bees, for a number of reasons, but we all know that a key factor is mites.

And yet it’s getting harder and harder to treat for them. Chemicals are losing efficacy, not to mention that it’s becoming more difficult to even get ahold of mite products that used to be commonplace.

Ever heard of heat treatment?

It's chemical-free, and very effective against mites with little to no side-effects. So why doesn’t everybody use heat treatment?

How It Works

The big idea behind the treatment is that if applied at the right temperature for the right amount of time, heat will kill mites without harming bees. This works because these two creatures have different biology. There’s a temperature and treatment length “sweet spot” that is above mite’s tolerance for heat, but below the threshold that's harmful for bees.

The History of Heat Treatment

Soon after Varroa destructor was first reported in Europe during the 1970s, beekeepers started experimenting with many different treatments, one of which was heat.

Thermal Hives

Several early solutions involved raising the temperature of the entire hive with the power of the sun, boiling water, or gas-powered burners. Heating up the whole hive had numerous downsides. The temperatures achieved fell across a wide range and weren’t consistent throughout all parts of the hive, which meant that the treatments weren’t consistently safe for queens, brood, or adult bees. Adult mites (and dead bees) would fall onto the floor of these hives. As a result, this procedure was more helpful for diagnosis than as an ongoing treatment doing little to actually get rid of the mites or even slow down their reproduction.

Thermal Boxes for Capped Brood: A Breakthrough

As Varroa started to spread throughout Europe in the 1980s, bee scientists based in Germany made some important refinements to heat treatment. Precise temperature control was crucial to avoid harming bees while effectively killing mites. Furthermore, targeting the mites inside the capped brood cells meant the temperature and duration of the treatment were more accurate which led to better results in terms of mite kill and fewer side effects in terms of harming bees.

Eventually, computerized temperature control systems, including heaters, fans, and sensors, were integrated into thermal treatment devices to achieve better, more consistent results that also had the benefit of causing less stress to the colony. Typically, temperatures are raised to between 104 and 108 degrees Fahrenheit for a period of two to three hours, which is lethal to Varroa mites but does not harm the bees.

This treatment is highly effective, however it doesn’t scale effectively for commercial beekeeping: 

Let’s say you’re a technologically-inclined hobbyist beekeeper in Germany today with 40 hives. You can buy a field heating unit for a few thousand Euro, take out your brood frames one-by-one, shake the bees off, put each one in the heating unit for a couple of hours, and repeat. You will be able to treat all the brood in that yard in a few days. 

But now, if you’re a commercial beekeeper with thousands of hives, imagine how long this operation would take. It’s just not feasible as part of your existing workflow. 

Could things be different with the BeeHome?

The Pros and Cons of Heat Treatment for Capped Brood Cells

Pros

Heat treatment offers some significant advantages over chemical solutions for mite control, including: 

• It can be used year-round (even during honeyflow)
• Mites are less likely to develop a resistance to the treatment (heat resistance is associated with multiple genes, rather than a specific chemical pathway).
• It doesn’t leave toxic residue in hives that can harm bees or contaminate the honey. 
• By targeting the mites within the brood cells, It disrupts the mite reproductive cycle and reduces their future population growth.

Cons

However, a few simple but significant factors have halted the adoption of heat at any commercial scale for several decades: 

• Removing, preparing and placing each brood frame into a heat chamber is incredibly labor-intensive.

The Future of Heat Treatment

Introducing the BeeHome 4: No chemicals, no labor, no cost, no mites!

At Beewise, our latest model of AI and robotics-powered beehive includes a heat chamber, designed specifically to effectively kill mites in capped brood while eliminating the challenges that beekeepers have historically faced with heat treatment:

• Our computer vision and other sensors can remotely identify when frames have a high volume of capped brood cells. 
• Our robotic arm can autonomously lift those frames, shake the bees off, and place the frame in the heat chamber. 
• Then, our power source, sensors, controls, and AI-powered software apply heat at precise temperatures and times. 
• Our robotic arm returns the brood frame to its hive, and the continuous cycle begins again with the next one. 
• All with no human labor, no chemicals and no additional cost.

Best of all, with a heat treatment chamber in every BeeHome 4, commercial beekeepers can enjoy the benefits of cost-effective mite control at scale. 

Want to learn more?