when varroa was first discovered here in the uk in Devon we devon beekeepers were all very concerned, headless chickens is i think the words.but we have come to terms with it and treat the mite at least once a year . I bayvarol my bees in the autumn, change my floors and brood chambers at least three times a year in an attempt to keep every thing clean and disease free. cut out all excess drone comb. and am now running my hives with varroa screens over at least a three inch floor or straight out to the atmosphere. the mite will not be eradicated despite the machinations of various departments of agriculture it is a case of grin and bear it.
A W Cannon. North Devon Beekeepers.U.K
take care and stay lucky