This thread is not getting much help. C'mon people!
How about this one:
BeeGo loses its effectiveness after the container is opened, if damp air is
in contact with it. Water neutralizes the efectiveness of n-butyric
anhydride as a bee repellant.
I first heard it here on BEE-L, I believe.
allen
http://www.internode.net/HoneyBee/Diary/