Natural treatments in bee hives

How to help bees to fight the Varroa mite


A bee with 2 varroa mites on the back.

Bees are having a rough patch. Everywhere in the world, beekeepers have noticed their bee colonies die off at an alarming rate. A lot of possible causes have been pointed out. Some are related to external factors, meaning to be related to the environment itself. The most commonly advocated external causes are climate change, habitat and biodiversity loss, pesticides, diseases and parasites such as the Varroa destructor mite. Beekeepers are trying out several treatments to fight Varroa.
In this guide we list natural treatments in bee hives against parasites and diseases.

What is Varroa?

It is an external parasite that attaches to the body of honey bees, and breeds within the colony by laying its eggs and feeding on the larvae.

Varroa destructor is known for causing brain development disorders. In elevated infestation levels it can be a direct cause of colony loss, but it is also a vector of several viruses.

This means that a colony, weakened by Varroa, can be easily attacked by further viruses and diseases.

Depending on climatic conditions, the damage caused by Varroa appears from autumn to early spring during the overwintering phase, leading to general weakening and often complete losses of colonies.

Although bee viruses usually persist as unapparent infections and cause no overt signs of disease, they can dramatically affect honey bee health and shorten the lives of infected bees under certain conditions7.

Even with proper management it is impossible to keep apiaries 100% free from Varroa mites.

Other pests and diseases

Apart from varroa and associated honey bee viruses, there are many other pests and diseases that may adversely affect colonies including Nosema parasite, bacterial infections like European and American foulbrood, tracheal mites and fungal diseases.

In contrast to Varroa, some of them, like Nosema, virus infections or foulbrood may damage colonies also during spring and summer.

It is also expected that within the coming years or decades, pests that are not currently present in Europe like the Small hive beetle (Aethina tumida) or the Trolilaelaps mites may appear and spread. The same scenario was previously observed with the Varroa mite.


What role does beekeeping play?

Decades of bad beekeeping practices may also have played an important part in the current “bee crisis”. Privileging productivity at all costs through the extensive use of selection may have induced a loss of genetic diversity.

Consequently, bees in commercial beekeeping have become overly dependent on the use of chemicals and antibiotics and are no longer able to cope naturally with new diseases and environmental challenges.

Bernard Nicollet thinks that chemical treatments against Varroa further weakens bee colonies. After years of treatment, Varroa is still here and worse, seems to have become resistant to chemical treatments. He personally keeps a few colonies aside to let natural selection do the job instead. And it works for him!

Unfortunately, most beekeepers do the exact opposite: They maintain and propagate the highly productive but weak bee breads:

For decades if not centuries, beekeepers have selected queens which offspring produced the most honey. However, this kind of selection is biased toward productivity and has not nothing to do with the ability of bees to survive pests and diseases.

Many apprentice beekeepers also buy queens and colonies from who guarantee a honey production off the chart.

Bernard Nicollet, a French beekeeper, explains that the way people rearing queens pick the larvae (usually based on their size) is likely very different from the way the bees themselves would have made their choice.

When playing with selection, everything comes at a cost. Artificial selection oriented towards productivity has induced a loss of genetic diversity in bees, which in fact is detrimental to their ability to adjust to a fast-changing environment and the emergence of new diseases and pests.

Overall, many prominent experts now agree that bee extinction in fact results from a complex combination of the above factors. That in fact makes the crisis even worse. While some advocate for the use of more chemicals, more antibiotics and even genetic manipulation, sustainable beekeepers think it will only weaken bees further.

In an attempt to fight off natural diseases and parasites, beekeepers have come up with a four natural strategies.

Four approaches to fight Varroa destructor

1) Privileging native species


In various parts of the world, bees with certain levels of Varroa resistance have surfaced. In isolated (often tropical) areas with no beekeepers (and consequently no treatments), the heavy selection pressure has produced populations which have more or less adapted and have developed certain levels of natural Varroa resistance. These colonies from the wild can contain relevant resistant material and can give us directions for selection.

Examples are:

Primorsky bees from Eastern Russia.

Bees on tropical islands like Antigua, Barbados and Mauritius (the natural population seems to have recovered after being decimated by Varroa).

Africanized bees (mix-breed, released by accident in Brazil and now present in South America and parts of the south of USA).

In Europe several other initiatives have started to search for a more Varroa resistant bee; Carnica AGT program, Buckfast-Primorsky, Buckfast-Brandenburg, Elgon bees, Lunden Apiaries, Black Bee Texel, Black Bee France, Gotland, Tiengemeten, John Kefuss selection, Waterworks Dune project, Las Palmas project, Stichting de Duurzame Bij and more.
But there is more.
In North America, it is prohibited to import queen bees for health reasons. Few large-scale queen bee breeders are responsible for renewing the stock, with each breeder selling hundreds of thousands of queens. They raise their queens from just a few of their best strains, which reduces the genetic diversity of the honey bee population and so weakens the bees’ defenses against various pathogens.

French beekeepers have imported honey bees from virtually the world over. Interracial hybrids, bred by artificially inseminating queens, can produce yields up to double those of the native black honey bee (Apis mellifera mellifera). The result is a wide genetic diversity in France, owing to continuing hybrid imports and to the genetic pollution of local honey bees.
In France, honey bee colonies that have survived for more than ten years without any treatment against the Varroa mite. This is an idea to be considered in the context of the spontaneous emergence of lines of Varroa-resistant honey bees.

On the other side, countries that select their honey bees and import very few, such as Germany and the USA, have not yet detected any Varroa mite resistance in their honey bees.

Lost in the endless rat race to higher productivity and seemingly powerless face to the extinction of bees, beekeepers may be tempted to work with imported species or subspecies.


2) Allowing the bees to eat more from what they produce


Bees may benefit from being fed artificially at times and even sustainable beekeepers feed their colonies.

Yet pollen and honey are still their natural food and obviously healthier than sugar syrup or any other man-made food supplements.

Taking away too much of the highly nutritive substances they produce, to give them junk food instead, does not contribute to improve the ability of bees to resist diseases and pests. Obviously! Just like us…


3) Using foundation-less hives


Bees naturally build cells of various sizes. Large bees emerge from large cells and small bee comes from small cells. Assuming that large bees are able to haul more nectar and thus increase productivity, most beehives use a foundation which is aimed at forcing bees to build only large-sized cells.

But sustainable beekeepers have noticed that using a foundation-less hive that let the bees build cells of smaller sizes drastically increases their ability to fight off varroa!

The foundation-less hive implies crushing and straining the comb at the time of harvest, which in turn allows cycling the old wax filled with pesticides and other detrimental compounds out of the hive. Replacing old combs regularly remains the best prevention against any kind of disease8.

Foundationless frames that enable bees to build cells of different sizes have been shown to help them fighting Varroa infestations.

4) Using essential oils and formic acid


A research published in the journal Parasitology Research suggests that the acaricidal (=killing acarians) properties of essential oils of lavender, laurel and thyme may help fighting off Varroa infestations9.

Essential oils are natural products, so their use may seem a sustainable alternative to synthetic chemicals10.

However, sustainable beekeepers warn that a hive is an ecosystem, which requires the presence of various micro-organisms to function properly. The chemicals contained in essential oils might kill these micro-organisms, which in turn would affect the bees too.

Bernard Nicollet also observed that some of his beehives were colonized by small colonies of ants. He noticed that these colonies were not affected by Varroa and came to the hypothesis that there may be some kind of symbiotic relationship between ants and bees11.

He thus started evaporating strips of cloth soaked in formic acid in beehives that did not have ants and were infested by Varroa. And it worked! He however advises that using this technique requires experience and a perfect knowledge of the life cycle of both the bees and the parasite.

The biologist and beekeeper Randy Oliver has come up with a similar solution. He also suggests the alternation of essential oils and formic acid, as it improves the efficiency of the treatment12.

Evaporating strips of cloth soaked with formic acid is seen as a ‘natural’ treatment because this acid is also produced by ants that sometimes colonize the hive.

Ecological systems are complex and fragile by essence. Ecologists but also countless indigenous cultures have long warned us that everything is linked. Seemingly insignificant alterations of any component affect the entire system. The extinction of bees reminds us that societal choices driven by economic considerations and the imperative of productivity may have serious environmental consequences.

The practices and opinions described here come from sustainable beekeepers with decades of experience.
At Bee4Life, we think that these practices are the best way to bring back bees that are able to naturally resist diseases. It will not be enough though. In fact, saving the bees rather requires a complete re-assessment of our relationship to nature. It also requires us to consume more consciously.

We are contributing to the extinction of bees every time we accept to buy food which production involved the irresponsible use of pesticides. It is time to stop buying the quick fixes offered by an industry aligned with the very logic of productivity that has brought us to the current situation. There is no quick fix to save the bees. Everyone pretending otherwise is either poorly informed or trying to sell you something. It is time to wake up!

Evaporating strips of cloth soaked with formic acid is seen as a ‘natural’ treatment because this acid is also produced by ants that sometimes colonize the hive.