Controlling pathogens in honey bee hives

Honey bees serve as an immense agricultural and economic source of influence, providing honey and vital pollination services. However, honey bees are also prone to disease and parasitic infection, which has contributed to their decline in recent years, along with pesticide use and nutritional stress.

Controlling varroa mites and similar parasites that plague honey bee populations is the key to protecting the honey bee, but in practice, it can be challenging. Knowing what treatments to use, if treatments exist at all, can be a source of struggle for honey bee apiary owners. Moreover, researchers are continually updating best practices and approaches for treatment.

In his new summary paper, CEID postdoc Dr. Lewis Bartlett shares the most recent guidance for treatment and hive health maintenance for improved hive management, as well as some potential future guidelines and weaknesses in the development of treatments for honey bees. 

One threat to honey bees is the small hive beetle (SHB), which reduce the productivity of the colonies by causing damage to the brood, pollen and honey stores. There are a number of recognized prevention methods, including ensuring that hives are placed in sunny areas on nonpermeable or dry soil that discourages the brooding of SHB populations. Additionally, ensuring that there are enough patrol bees to secure the hive properly to fend off invading SHBs and the provision of mechanical traps that are big enough for the beetles but not big enough for the bees. 

One main issue preventing the elimination of SHBs is that it’s very difficult to find an insecticide that will work on them but not cause significant health issues for the bees.

Current recommendations for virus treatment in honey bee populations often involve preventative measures through honeybee holistic health practices, which include lowering exposure to pesticides and good nutrition. This calls for practices such as sugar supplementation as well as less common pollen supplementation to reduce pathogen load in the honeybees. 

Another way to prevent viruses from infiltrating honey bee populations is through the control of varroa mites. Varroa mites inhibit the immune system of honey bees and are known vectors for several diseases that impact honey bees. 

Varroa mites have any number of control methods, but they remain a substantial issue due to their ability to quickly develop resistance to antibiotics, though research on the mechanisms behind this development of resistance is progressing quickly. One effective method to control varroa mites can be the application of treatments like thymol or formic acid, but these must be applied carefully. If applied at too high temperatures or at too high doses, they can fumigate the hive and lead to absconsion or widespread brood death.

Efforts are currently in progress to address existing gaps in research as it pertains to the treatment of some of these pathogenic threats faced by honey bees. On the frontier of biological control research, supplementary feeding of phytochemicals has shown promise, as well as microbial supplementation. Another new approach involves phage therapy, which involves the use of bacteriophages that will attack some of the pathogens that threaten bee populations. 

In the realm of chemical treatments, one of the top priorities is attempting to find a functioning acaricide in order to control varroa mite populations. Another interesting area is the research of essential oils, which may have chemical components that could be useful in the treatment of pathogens, but further research is required.

While research into the treatment of pathogens in bees has made substantial progress in the past few years, it’s also worth noting that there remain several barriers to treating these pathogens in bees. For example, treatment methods tend to be costly and outside the realm of possibility for many smaller apiary productions. Additionally, the approval process for some of these treatments can be extensive, especially as some treatment methods have significant impacts on human health.

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By Amanda Budd