Keeping bees is a challenge and losing colonies is not a rarity these days. Each spring, beekeepers are more frequently replenishing empty hives with new packages or nucs (nucleus colonies), which can be expensive after several years of continual losses. There are many factors contributing to the decline of honey bees in the US including poor nutrition, increased pesticide loads in nectar and pollen, and higher pressure from pathogens and parasites. One of the most serious problems to honey bee health is the varroa mite, Varrroa destructor. There is ample research on various varroa mite management methods, which can vary from using hygienic genetic stocks, to chemical and non-chemical treatment methods (including drone comb removal, inert dusts or essential oils, screen bottom boards). But, how does one go about implementing these multiple approaches to combat various honey bee pests?
(Left) An IPM scout inspects plants for disease. (Right) “The Integrated Control Concept”, a seminal article published in the October 1959 Hilgardia, provided the foundation for modern IPM.
Let’s start with a little bit of history…
The term Integrated Pest Management (IPM) was coined in 1972, even though research on this topic began at the University of California in the 1950’s with Vernon Stern and his article “The integrated control concept”. The concept and impetus for IPM grew out of discontent with using a purely insecticidal approach to pest management because the overuse of chemicals was proving to lead to ecological distress, chemical resistance and to the creation of ‘Super Bugs’ resistant to all chemicals during the mid 20th century.
IPM and honey bee pests
The IPM strategy comprises a series of tactics that focus on the long-term prevention of pests and damage through a combination of different management techniques. It is not only a strategy but an attitude that emphasizes creating conditions to allow natural mortality factors to work efficiently while correctly identifying, monitoring and diagnosing pest pressure prior and their responses to treatments. Overall, IPM applies a holistic approach to the problem of managing harmful insects, weeds and plant diseases, and it takes place on both the agricultural and nonagricultural settings, including gardening and beekeeping.
When the varroa mite was introduced in the US in the 1990’s, beekeepers heavily relied on chemical treatments to control varroa populations. Miticide overuse and misuse led to the quick development of mite-resistance to commonly used chemicals including fluvalinate (Apistan) and coumaphos (Checkmite +). Beekeepers today have a very different relationship with these miticides. Now it is common knowledge that the best approach to control mites is not as simple as applying a lot of miticides, but it requires implementing a rotation of approaches. The goal is not elimination of every mite because that is impossible, but rather to prevent mites from exceeding a threshold level that could significantly damage colonies.
Central to IPM is the proper identification of the responsible pest, learning about its life cycle and biology, monitoring populations, establishing thresholds, choosing appropriate management tactics and evaluating the results. There is a series of tactics that are employed to effectively suppress pests using IPM approaches. These tactics can be visualized in a triangle with cultural tactics serving as the base, then using physical and mechanical tactics, followed by biological control tactics. Chemical tactics are at the top of the pyramid and should be considered as the last resort.