CHAPTER 4 : Varroa Mite Management
As with any area of interest, from stamp-collecting to goat-herding, there are bound to be enthusiasts who are only too willing to tell you that their way is the right and only way.
Don’t listen to them. You are on a learning curve and should be drawing information from as many sources as you possibly can. As you learn more about the art of beekeeping, you’ll be able to sort the myths from the realities, but as a beginner, it’s helpful to have a bit of a primer on some of the myths often propagated in the world of apiculture.
One of the most prevalent myths is that organic beekeeping, which precludes the use of any chemical means to control colony health, is somehow “wrong”. It’s not only “not wrong”, it’s responsible beekeeping that can prevent colony collapse, through the use of naturally-derived chemicals.
To date, two strains of bee have been developed which are entirely resistant to the varroa mite. These are the Russian and VSH (varroa sensitive hygiene) bees. They have been scientifically developed to resist the mites. The VSH bee is particularly interesting, as the drone of this strain can “smell” (although it’s not yet clear whether the smell they’re responding to is the damaged drone larva, or that of the mite) something going on. When this occurs, the worker will open the infested cell and eject the damaged larva, thus depriving the mite larva of food.
Some areas of the world are less susceptible to infestation. Higher elevations tend to provide some protection, as well as plentiful sunlight. But environmental conditions don’t imply a varroa-resistant bee, as those conditions aren’t replicated everywhere. Migration via sale to beekeepers in other areas will result in the same peril to these bees as any other.
Varroa destructor mite
These parasitic mites are something you need to know about and something you need to take seriously. In the movement for “natural beekeeping” (which really doesn’t exist, as you create an artificial environment in order to keep bees), the varroa destructor mite is virtually ignored. There is a type of Holy Writ read by the ranks of organic beekeepers which eschews treatment of bees to protect them against this parasite.
But a recent survey of a beekeeping organization in the State of California revealed that more than 50% of the colonies started by its membership had died. By adhering to the Holy Writ of organic beekeeping,
these members had endangered their colonies and, as a result, lost their colonies. Worst of all, those who had done so were doubtful they’d ever have another go at beekeeping. So it’s important that you put in place measures to combat the proliferation of these potentially colony-murdering parasites. These eight-legged pests are a little more than 1 millimeter in length and about 1.5 long. That sounds small, but imagine one clinging to a bee. Brown in color, they adhere to bees to enter the brood cells and once the cell is capped, begin to lay eggs, reproducing about every ten days. When the developed bee (typically, a drone) leaves the cell, the newly born varroa mites leave with it, infecting other bees in the colony.Adult varroa suck the blood of bees in the colony, making them far more prone to diseases and infection. There are few strains of honeybee which are immune, and about ten per cent have a native ability to combat the effects of the varroa. Other bees are fully susceptible.
Varroa treatment and management
It’s very important to understand that those beekeepers who refrain from following effective varroa mite management lose the most colonies. Every beekeeper, without exception needs to adhere to a rigorous program of mite management, if their bees are to survive the winter. Effective methods are as follows: •
- Amitraz-based (ApiVar)
- Formic Acid
These four mite management products have been proven effective over several years. They are all fumigants and they are all derived from natural base elements. This means that using them will demand that you carefully follow instructions provided with the product you choose, concerning ideal temperature for maximum efficacy. Also, any screens in your bee palace should be blocked in order to ensure the treatment works.
Varroa mites, like other pests and parasites, are capable of developing resistance to certain substances over time and that’s the case with a number of products and methods. One of these is hop oil. This product has not been proven to have any effect whatsoever and has actually resulted (in some areas) in a higher rate of colony collapse than colonies which were not treated with anything. Another method which has stopped being effective is Sucrocide. This will have absolutely no effect on the survival and reproduction of the varroa mite.
One method which does employ any product is drone brood removal. Because varroa mites prefer these colony members over others, removing the entire brood, once capped (with the mite’s eggs inside, as discussed earlier) and then freezing it, will kill the mites’ eggs. Of course, the brood will also die. This method, however, must be practiced across your entire operation. You can’t do one brood and not do them all, in other words.
A screen bottom board is also touted as a method of mite management and has seen mixed results. While this method provides some reduction in colony infestation, it has not been proven to increase the rate of survival of colonies which have been infested. A screen bottom board is best used in concert with other methods. On its own, it’s not effective.
Finally, encouraging smaller cell size presumably inhibits the ability of varroa mites to lay eggs on the drones inside them. But a three-year survey exploring the veracity of this claim revealed that it is not at all effective.
The upshot is that, while we’re trying to help bees here by creating as natural environment as we can for them, not using a product to keep them healthy is not an effective way to do that. In fact, by eschewing chemical recourse to mite management, beekeepers have been learning, the hard way, that this is just another way of promoting colony collapse.