Debra writes:

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    make a small hole in the lid of a jar, put some jam or fruit inside, and
half fill it with water. The YJ's, assuming they act like British wasps, are
attracted by the smell, enter the trap and drown. The bees aren't attracted.
I don't know how effective this would be round hives, my parents used to use
them in the kitchen when I was a kid, and they worked there. If the problem
is YJ's entering the hives, you could try mesh floors and permanently reduced
entrances.

Regards,

Robert Brenchley

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