Varroa destructor is an external parasitic mite that was introduced into the United States in the 1980s. The USDA National Honey Bee Disease show in their Survey field samples and BIP’s varroa assessments indicate that mites, and the viruses they carry, continue to negatively impact US honey bee colonies. A majority of beekeeping operations in the US have mite loads in excess of damage thresholds during the critical fall months and our Tech Transfer Team regularly sees evidence of colony-level damage from varroa mites in many of the over 10,000 colonies they monitor each year.
BIP works closely with a sister surveillance network – the National Honey Bee Disease Survey – which involves sampling wax or pollen in over 400 apiaries nationally each year and uses the trusted USDA/AMS National Science laboratory for pesticide analysis. A complete list of these findings are publicly available. BIP also offers pesticide sampling/analysis for all of its participating beekeepers and BIP is asked to conduct independent assessments on colonies that appear to be suffering due to an acute pesticide kill. In those cases, BIP performs a full colony inspection, taking pest, pathogen, pesticide and viral samples to rule out other causes of mortality.
Colony loss rates (mortality/turnover rates) are different from population decline. While many colonies are lost each year due to a number of factors, colony loss does not necessarily mean that honey bees are in decline. Beekeepers can make splits or bees can swarm to make new colonies so while there are turnovers each year, the population (overall number of colonies) remains stable. Replacing colonies comes at a great cost to beekeepers and should not be underappreciated.