Before OA were there unexpected colony losses? Were there treatment failures for unknown reasons? Were there seasonal variations in buildup, harvest volumes & colony strength despite consistent treatments?
I thought this post from The Apiarist was timely.
@jamesc & the rest of us can’t hope to have our questions answered while no evidence (as apposed abundant opinion) on offer.
Without a sufficiently powered controlled randomised, and hopefully observer blinded, study there will always be room