Fall Feeding: Preparations to Survive Winter & Newfoundland Hopes to Remain Varroa Free!

Friday 25 September 2020

Imagine beekeeping without Varroa mites!  What you are imagining is real and exists in Newfoundland.  The NL beekeeping association has just released a Varroa Action Plan and this week we learn about their strategies to remain Varroa free!

This is one of the most important times in the beekeeping calendar when we are preparing our hives for winter.  Especially after a difficult drought season, we need to ensure our colonies have the resources to survive winter.  Read on as we consider feeding and the importance of getting calories into our hives.  

Fall Feeding: Preparations to Survive Winter

Now, while the temperatures are still relatively warm, we should all be feeding in preparation for winter.  Have a look at ATTTA’s Fall Honey Bee Management Guide as an excellent source of information on getting your bees ready for the cold season.  

When it comes to fall feeding, beekeepers often ask, “How much feed do bees need?”.  This is like asking, “How long is a piece of string?”  Let us look at a couple of facts which can help beekeepers better understand the feeding process.  

Firstly, focus on the hive weight and begin feeding up from this point towards an expected winter-ready poundage.  This fall, in certain areas of our region, bee hives are starting out light and therefore will need more feeding!  To overwinter in our Atlantic Canadian climate, each colony requires 27-36 kgs (60- 80 lbs) of honey.  An experienced beekeeper can do the “heft-test” by lifting the back of the hive and judge the stores available in individual colonies.  Thirty-five kgs of honey is a good guideline weight for winter preparation.  To achieve this weight, the bees need to have access to either nectar or sugar solution.  As there is little nectar available after honey harvest, a substitute must be supplied!

We have a relatively short window of time to replace the “energy” we have taken when harvesting honey.  Nutritive energy is delivered as a solution of water (H2O) and, most commonly, sucrose (C12H22O11) in the form of white crystalized table sugar.  Sugar is dissolved in water at a ratio of 2:1 by weight.  The resulting solution is around 67% sugar (with 33% H2O).  This is referred to as percentage by weight and is a simple way to describe concentration.

When sugar, as the solute, is mixed into the water, as the solvent, the volume does not increase linearly during dissolution.  Intuitively you may expect two kilograms of sugar mixed with one litre of water to make near 3 litres total volume.  This assumption does not account for the large amount of space water has between its molecules.  This space allows the sugar to mix in without initially increasing volume.  Once the sugar has filled this molecular space, only then will additional sugar increase the volume.  When mixing 2 kg of sugar with 1 kg water (1 litre H20 = 1 kg) we get a total volume of around 2.25 litres of 67% sugar solution.  The saturation point of a solvent is the point at which no more of a solute can be added and at room temperature we are very near saturation point with our 2:1 sugar solution.  The saturation point increases with temperature which is one reason why warm water will more easily allow sugar to dissolve to a higher concentration.

Let us consider some hypothetical numbers!  We need to realize that each litre of our 67% sugar solution has approximately 150 ml of excess water.  The bees must remove this additional water during the conversion and storage process to achieve the 17 – 18% moisture content of honey.  So, one litre of sugar solution makes 850 grams of honey.  This weight of honey will contain 2550 kilocalories.  An average hive will need around 100 000 kilocalories for our Canadian winter.  This means that if your hive’s only source of winter stores is from fall feeding, it would need around 40 litres of sugar solution (i.e. 40 litres sugar solution = 34 kg honey).  Our theoretical 40 litres of sugar solution will contain 6 litres of water which the bees must remove.  This takes a great deal of energy as well as favorable ambient temperature and humidity.  An average top feeder is 15 litres capacity so this would need to be filled 2.6 times.  When considering the above information, do not forget that in practice there is some honey in the hive already?

Remember hive weight is the ultimate test of how much we need to feed.  Sugar syrup can only be converted to winter stores during relatively warm weather.  The initial hive weight indicates the amount of honey in the hive and this specifies the amount needed to achieve our goal of 35 kg honey.  

Further information on fall feeding:

Feeding Honey Bees

Fall Honey Bee Management Guide

Newfoundland Hopes to Remain Varroa Free!

“Getting Varroa would be a disaster for beekeepers and our industry,” said Newfoundland Beekeeping Association president, Rodney Reid. “Unless we’re well prepared for it, the parasite could wipe out 90% or more of our stock. The management of our bees would become much more complex and expensive in terms of time and money. It would discourage new beekeepers and possibly bankrupt our established and new commercial operators.  These are some of the consequences we’ve seen elsewhere in the world.”

This statement comes with this week’s release of a “Varroa Action Plan for Newfoundland and Labrador.”  This is a plan to deal with the arrival of the parasitic mite, Varroa destructor.  As the rest of the Atlantic provinces’ beekeepers battle Varroa, Newfoundland is one of the few remaining Varroa free zones in the world and the NL beekeepers association is working hard to keep this status.

Figure 1 Images of Varroa Destructor from Varroa Mite Biology and Diagnosis, Ontario Beekeepers Association

If Varroa does come to Newfoundland, the association suggests that the most likely way that this would occur is through illegal importation of honey bees.  Knowledge of the devastating effects that the Varroa mite will have on Newfoundland’s beekeeping industry is the main deterrent to prevent this route of infestation.  The Newfoundland industry, through its beekeeping association, intends to inform beekeepers of the dangers of Varroa and actions to prevent its spread.  They aim to provide this information to beekeepers and the general public through training and workshops.  The first of these training sessions are scheduled around the island between October 3 and 11.  Training will be provided by experienced beekeepers from New Brunswick where Varroa has been established since the early 1980s.

For more details on the action plan and information on how to register for the Varroa workshops, visit the NL Beekeepers Association website: https://www.nlbeekeeping.com/

Connecting with ATTTA Specialists

If you’d like to connect with ATTTA specialists or learn more about our program, you can:

visit our website at https://www.perennia.ca/portfolio-items/honey-bees/

Email abyers@perennia.ca

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