So you’ve got the bees all fed and ready to be wrapped for winter — but just suppose, there’s a spell of warmer weather, and you see a chance to feed a bit more. You’ve even got a few pails of sugar syrup leftover on hand… but the Fumagilin B has already been added to the syrup.
The question, then, is:
What is the life expectancy of Fumagilin B in sugar syrup?
Should you mix up another batch, or will the leftover medicated syrup still protect your bees from Nosema through the winter?
According to the people at Medivet, in a recent email exchange with inquiring beekeepers, it’s not possible to give an authoritative answer to this question because so much depends on the storage conditions for the syrup.
In general, however, it is not recommended to make up your medicated syrup very much ahead of time, or to store it for long, because the Fumagilin B is less stable in sugar syrup than it is once it’s been processed by the bees.
In other words, medicated syrup can be stored by bees in the hive — but the beekeeper can’t do it without the Fumagilin B losing much of its power to combat Nosema.
A “best guess” estimate is that syrup may lose about 20% – 30% of its potency in sugar syrup stored for 4 weeks, and another 50% if stored for much longer than that. The bees are likely to get “some benefit” from the old syrup, but it would be best to ensure that the bees have been well fed with freshly-mixed medicated syrup to ensure that the Fumagilin B will be effective.
I am new at this and would like to know the mixing instructions for Fumagilin-B. Can I mix a half gallon at a time or can I mix a gallon of syrup at a time? I have three hives and they
are working at this time.
Thank you for your response.
You can mix as much or as little sugar syrup as you need, Donald. Just follow the package directions for your Fumagilin-B and divide the amount to fit the amount of sugar syrup.
It helps to dissolve the medication in a bit of water first, and let the syrup cool to just warm before you mix in the dissolved Fumagilin.
You don’t say where you are, but if you’re down south of us and are already into forage season, don’t medicate with honey supers on. You don’t want the Fumagilin-B to be in the honey you’re going to harvest!
I just made up a batch for the first time, I had the same issue as most asking about the amount of water to use. I ended up taking a big tall pot and adding one gallon of water and 15lbs of sugar, some honey for aroma and color and then when it was all cooked up I just took a dipping pot and poured it into a cleaned out gallon milk jug leaving enough room for the dissolved medication of one rounded teaspoon. I will be giving them 2 gallons before I get the hive ready for winter. My only issue was with the behavior…aggressive and a little crazy from all that sugar…I had to keep the dogs in the house and warn the neighbors when I noticed some young new bees landing on the shiny cars and bothering me outside.
I use hive top glass bottle feeders (2 qt). Does Fumagilin-B degrade with sunlight?