[Bumbles]

I recently attended our monthly meeting of the MCBA (Montgomery County Beekeepers Association) on hive inspection. Our invited speaker was Rob Snyder, who worked as an inspector for several years, and is currently working with Penn State U. with their continuing studies of honeybees. He informed us that exposure of Fumagillin-B to the UV rays of sunlight rendered it ineffective. He didn't know how long of an exposure caused this, but that it was only recently discovered. My question to him was "what possible negative effect would feeding it to the bees have? He said it as of now is unknown. Has anyone else heard of this? What effect(s) could this have on the bees?

 

[Beeslave]

Yes, sunlight will make it ineffective. How long does it take? I don't know but a beekeeper I know keeps his large(1,000 gal+) poly tanks covered even if it is only a week that the mix stays in there.

The negative effect would be that the bees don't recieve the medication you want them to. As for side effects of the compounds that are left after sunlight degrading-I don't know. Medivet would have the answer for you if you called them.

 

[honeyshack]

I have been told by our local University Apiarist that Fumagilin b is rendered inert in about 45 minutes to an hour in sunshine. Solid white pails happen to protect it a bit more however when feeding put an empty super and an out lid over the pail to be sure.
Any livestock medications which come in dark bottles should be stored in a dark place. Every bottle has storage instructions for temps and light.

It has also been said that mixed in syrup, over time it looses it's effectiveness. However when the treated syrup is capped, it retains the medication

 

[peggjam]

Heat will also render it ineffective, so when mixing with sugar syrup always allow your syrup to cool to room temp before adding the fumigillian.