Treatment of KBH Bees in The Age of Varroa Destructor

Treatment of KBH Bees in The Age of Varroa Destructor

One of the talks I give to groups is entitled, “If we die, we’re taking you with us.” It focuses on the importance of bees to our food supply. Yes, it’s true. Close to two-thirds of everything we purchase in the produce, dairy, and meat departments at the grocery store are the result of bee pollination. But I’m not writing about this today. I’m here to educate you on the importance of how we treat for mites at Killer Bees Honey. Thus, enabling our bees to do what they do best: pollinate. 

There are four fundamental factors that affect bee health: pests, pathogens, pesticides, and poor nutrition. All are interrelated. This was a disastrous year for many WNC Appalachia beekeepers. The heavy rains washed out pollen and nectar from the flora. Conserving energy, many resource-rich trees shut down their blooms. When spring bees should have been storing 3 - 5 pounds of honey a day per hive, most if not all colonies began starving. Desperate for food, bees began robbing each other's hives. Robbing bees from stronger hives and drifting bees from collapsing hives carried Varroa destructor mites to other colonies. Mites are vectors for up to 20 different pathogens. Among other viruses, they transmit Acute Bee Paralysis Virus (ABPV),  Israeli Acute Paralysis Virus (IAPV) and the deadly Deformed Wing Virus (DWV). Mites now constitute the largest and deadliest threat to the honey bee in the United States since their introduction from Asia in 1987.

The alarm was sounded in the 1990s. Commercial beekeepers reluctantly began treating their bees with synthetic compounds, mainly Fluvalinate, Coumaphos and Amitraz in off-label applications. What they didn’t anticipate was the mites rapid evolutionary resistance to these pesticides. Mite reproduction occurs when a phoretic female mite enters a cell before it is capped. After capping, she will lay one unfertilized egg with a single set of chromosomes (haploid), which results in a male. Then, she produces fertilized eggs that have two sets of chromosomes (diploid) with the outcome being females. The eggs hatch; whereupon the male mite fertilizes his sisters. The mites grow and mature by feeding on the bee larvae, as they feed, they transmit the earlier mentioned pathogens. When the varroosis infected bee emerges from its cell, anywhere from five to seven female mites exit with it. The incestuous nature of the mite reproductive cycle caused a rapid resistance to synthetic pesticides - the beekeeper might have killed 95% of the mites by using Fluvalinate, but the remaining 5% of the offspring were the beginning of a chemical resistant evolution. Within ten years, most synthetic pesticides became worthless as treatments, but are still being used by commercial beekeepers to this day.

Amitraz is still in use with a high degree of success. The French pharmaceutical company, Veto-pharma is the largest and most reputable firm in the world utilizing amitraz in its Apivar strips. Apivar is used throughout the United States and EU countries with the treatment of five million hives every year. It was just licensed for use this year in the United Kingdom. There is some disagreement among authorities as to whether mites are becoming resistant to it. Recent studies also show that synthetic pesticides are effecting drone sperm levels which in turn affect the overall health of the colony because of poorly mated queens. More disturbingly, DWV appears to be evolving and becoming more virulent than its mite host. 

Many WNC beekeepers were overwhelmed with mite infested hives this year. I’ve never seen such high mite counts in my apiary. We treat our hives using organic methods. Mostly thymol or formic acid based products. Within weeks, I would have a hive go from below the threshold of <6 mites per 300 bees (1/2 cup) to 71 mites in 300 bees. One of our state bee inspectors, Lewis Cauble found a beekeeper whose hive had an unprecedented 158 mite count. That is a 53% (52.66 mites /100 bees) infestation rate! It’s becoming an endemic and depressing problem; I know many beekeepers who are thinking of getting out of the business. It is profoundly sad to watch your hives die over the winter, all resulting from their weakened condition. 

Beginning in 2019, we are radically changing our pest monitoring and control strategy. Our integrated pest management (IPM) practices will still involve using, and only using organic methods, but KBH shall be even more aggressive in its efforts to control the mite population: 

  • We will need to buy nucs and packages this spring to make up for colony losses. All packages of bees will be checked for a baseline mite count, then fumigated with oxalic acid (OA); a harmless procedure involving the use of a vaporizer gun and 1/4 teaspoon of OA per hive. 
  • Nucs, once established, will be checked for a baseline mite count then, treated with formic acid strips for seven days.
  • All new colonies, whether being treated with OA or formic acid will be treated simultaneously in the apiary. This should eliminate the problem of phoretic mites hitching rides on drifting bees. 
  • Tours of KBH start in May. Our guests shall volunteer to learn and perform a mite count during the hive inspection. We will thus be able to monitor four different hives a week; 16 per month.
  • We are lowering our economic/action threshold. If one hive in the apiary reaches a threshold of >2% infestation, then all hives are treated. Again, this should eliminate the issue of drifting bees from an untreated hive to a treated hive.
  • We have two nectar flows in WNC. Between them and when the honey supers are off, we will fumigate the bees using OA every five days over twenty days (four treatments). We will monitor and then re-super for the sourwood flow.
  • After the sourwood flow in August, all hives will be treated. TBD how.
  • Between Thanksgiving and Christmas, when the hives go broodless, all hives will be treated using OA vapors. We did this two weeks ago in our apiary. This kills any phoretic mites going into the spring.
  • Coordinate with neighboring beekeepers our treatment days to eliminate mites on drifting bees from nearby apiary's. FYI: France actually has calendared treatment dates for beekeepers to follow for this very reason (would never happen here in the states). 
  • Reevaluate our strategy in the fall and adjust our pest management for 2020.

We are beekeepers. Not bee havers. The difference is that we manage bees in an ethical and sustainable manner. Killer Bees Honey promotes an organic, natural approach in the systematic caring of our charges. Whether working in the apiary with a mentee, giving tours at our mountain top apiary, or speaking to the public, our mission is to disseminate knowledge related to improving the well-being of the honey bee and her importance in The Grand Scheme. What is at stake is the quality of life for our bees, the quality of the honey they produce for our customer and finally, pollinating the flora that gives our bees sustenance and reason for being.

(The featured photo depicts maturing mites feeding on a honey bee larvae)