It was another busy summer here at the Honey Bee Research Centre! We manage our beehives for research and education but we also count on an income stream from our hive products.
Our 2021/2022 winter losses were 10% but another 10% came through as weak hives. Some weaker hives built up on their own, and others were boosted with bees from other colonies. We were relieved by the low colony loss and recovery rates we experienced as it was certainly a tough year for wintering bees.
Our Low Varroa Growth (LVG) research project protocol involves splitting all the hives in the project each year. To make the LVG splits, we removed the queen from the original colony and divided the hive in two. Each half colony was then given an LVG queen cell. Due to the cool spring, we waited until early summer to make up the splits. By this time drones were abundant enough for good queen mating. In the five generations of this breeding project, we have achieved a six-fold decrease in mite population growth. The colony divisions required for this project made up for our wintering losses, so we didn’t need to split other colonies.
During COVID-19 we were required to reduce our staff and volunteer numbers so we couldn’t offer queen sales. This summer we resumed queen sales. We set up 3 cell builder colonies in mid-May and grafted larvae weekly until late July. The cell building went very well this year, and these three colonies produced a total of 1,304 queen cells. We mated queens locally and at our isolated mating station on Thorah Island. We raised both LVG queens and Buckfast queens from four breeders queens. Most of the queens we rear are used in our own colonies but, while we are at it, we raise a few extra queens to sell.
Early summer nectar and pollen flows were good this year. By the time we made our splits, most of our hives already had at least one super full of honey. Midsummer conditions became drier and the Guelph area received very little rain until late August. Through this time our bees ate as much honey as they produced. The honey we harvested in late July had a minty taste indicative of an early summer basswood nectar flow.
In late summer, we observed less than optimal brood production, weaker colonies, and even some brood death as many colonies had little or no honey and pollen in their brood chambers. They did have honey in the supers we had left in place. We are still concerned about these conditions as our colonies will likely have smaller winter clusters. We did get some honey and pollen from golden rod flowers in early September but not the bumper fall crop we were hoping for.
Monitoring mite populations in our 300 colonies is a labour-intensive but very important task. Three times a year, we place a sticky paper under the screen bottom board of each hive. We leave the sticky papers in the hive for 3 days, where it collects any mites that fall. We removed our mid-summer sticky papers from the hives on August 5 and with the help of volunteers, interns, and summer students, we counted the mites on the sticky papers. We were relieved to find that our mite levels were quite low. We decided not to perform any mid-summer mite treatments since we need mites for our research projects!
We believe that a cool spring, splitting hives, requeening, introducing queen cells, screen bottom board use, and good genetics all contributed to the lower mite levels in our hives this summer. Low mite levels in early August gave us the confidence to wait until after the fall honey flow to apply mite treatments.
Please have a look at our four new YouTube videos on mite controls. One of these describes alternative methods of reducing mite loads. Since the Varroa mites reproduce within brood cells, these methods (which often involve disrupting brood cycles) can diminish varroa mites’ reproductive capacity.
Mid to late September we inserted Apivar strips in all our hives and we will do an oxalic acid trickle treatment in early November. We do the oxalic acid treatment to kill off any mites that may be developing resistance to Apivar, and to eliminate mites that could be reinfesting our hives from nearby colonies.
