The COMB Project Update, November 2019

  • The second bee-year of the COMB project was a time of splitting, swarming, and honey production. After winter losses of 62.3% in the chemical free (CF) management system, 13.0% in the conventional (CON) management system, and 14.7% in the organic (ORG) management system, we set out to recover our numbers.
  • If a colony had at least 8 frames of brood in the spring, it was split to make a second colony. The split colony was left to requeen itself. Subsequently, if a colony had initiated swarming by making queen cells, the colony was split. Again, the split colony was left to requeen itself. The overwintering losses in CON and ORG colonies were easily made up by splitting. Some CF colonies were able to be split, but there were not enough colonies made to completely make up for losses.
  • Despite our best efforts, only 11 PA colonies did not swarm. That means that only about 10% of the colonies made it through the season without a brood break.
Our management systems


  • Throughout the 2019 season, the colonies were visited every two weeks starting the first week of April. *Each month, alcohol washes were performed on all colonies and summer treatments (see table) were given to colonies in a single “sub-apiary” if one colony exceeded the threshold of 1% infestation in an alcohol wash.  A sub-apiary is defined as the colonies in an apiary that are in the same management system.


  • In late August, fall treatments were applied (see table) and the colonies were generally not disturbed for 6 weeks.
  • Varroa mites were well controlled in CON and ORG colonies. They were much higher, beginning in late summer, in the CF colonies.


  • All of the COMB colonies combined made over 5750 pounds of honey.
  • Management system did not seem to affect the amount of honey made by each individual colony.


  • Going into the winter of 2019-2020, we have 218 colonies; 42 CF, 87 CON, and 89 ORG. We’re hoping for great survival!

Post contributed by Robyn Underwood, PhD, Assistant Research Professor



4 Responses

  1. Are there any updates? I would live to know the survival rate from spring of 2020 – and beyond!! Thank you for your fascinating research.

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