The Impact of Mushroom Extracts on Honey Bee Health

Over the last fifteen years honeybee populations have experienced massive die-offs and increased disease pressure. Much of this is in direct relation to the presence of Varroa mites and 8 different viruses. A multiyear survey published in 2016 to gather disease baselines saw winter colony losses
average 30% and annual hive mortality was about 50% for commercial beekeepers (Traynor, Kirsten S.). In an article published by Cornell highlighting SARE project FNE10-694 the author estimated over 20,000 new hives are imported into New England every year (Englander, Aaron).
Honey bees are an essential part of the food system in the northeast, globally they are the third most economically important agricultural livestock. Despite the importance and wide spread use of honeybees, consistently effective treatments to limit Varroa mites and decrease viruses have not been found or made commercially available. Honey bees provide pollination for many important crops in the northeast including apples, blueberries, cranberries, cherries, and squash. According to a Cornell study published in 2012 “honeybees pollinated $12.4 billion worth of directly dependent crops and $6.8 billion worth of indirectly dependent crops in 2010” (Ramanujan, Krishna). The health and viability of the honeybee is essential in maintaining a sustainable food system in the northeast. By decreasing the annual mortality rate of honeybee populations farmers economic viability can increase. Beekeepers would need to spend less time and money on purchasing and reestablishing their hives annually. Farmers with apple orchards in New Hampshire, cranberry bogs in Massachusetts, blueberry barrens in Maine, sunflower fields in New York will more effectively manage their own hives or be able to rent healthier bees for less. Viruses found in bee hives are typical and can be managed by a healthy colony without overt symptoms being expressed. When colonies begin to experience further stress these viruses start to proliferate and cause extreme damage in a beehive. The Varroa mite is the primary infection route for the viruses, this is the deadly spiral weakened bee hives get into. An increase in the expression of viruses, due to a weakened immune system under Varroa pressure, leads to decreased hive health and activity. This leads to an increase in viral expression and Varroa mite damage which then leads to a further increase in Varroa pressure. These cycles feed of each other until the hive dies. To stop this cycle either the Varroa mite needs to be eradicated, which has proven extremely difficult, or the immune system of the bee needs to be strengthened to stop the initial increased expression of the viruses due to Varroa infestation.

This approach was modeled after the results from the study published October 4th 2018 titled Extracts of polypore Mushroom Mycelia Reduce Viruses in Honey Bees. In field trials conducted in this study “colonies fed Ganoderma resinaceum extract exhibited a 79-fold reduction in DWV(deformed wing virus) and a 45,000-fold reduction in LSV(lake sinai virus) compared to control colonies” (Stamets, Paul). In cage trials measuring bee survival rate, bees fed a sugar broth with extracts of Fomes had on average 50% more bees surviving over the course of 30 days. These are massive decreases in the expression of very common viruses that greatly damage honeybee health. At the same time increasing the survival rate of bees leads to strong hives that are capable of dealing with different stress factors. These factors of decreased virus presence and increased survival rate likely means overall bee health is improving from the application of these extracts. The above study primarily studied mycelial extracts of two mushroom genuses Fomes and Ganoderma. Both of these mushroom genuses are commonly found in the northeast. Rather than focusing on mycelial extracts this study looked at using commonly available mushroom fruiting bodies that could be gathered or easily cultivated on farms in the northeast. The same genus of fungus was used but a different anatomical part of the fungus, the mushroom, was used instead of the mycelium.