Here in the UK resistant varro mites are spreading, slowly at the moment, but as with the mites themselves the rate of spread will no doubt increase so we need to find alternative treatments. In my own experiments I have tried Apiguard(too temperature depenant, and the results are too variable), Formic I have tried on Mite Wipes, and three different evaporators( results good but nasty stuff to use).
 So oxalic acid dribbling or trickling seems to be a usefull method to use especially as it is done when there are few pressures from other beekeeping activities.All literature I have read on the subject states that oxalic should be  applied during the broodless period in late autumn,assuming this was when the most mites would be hit. This autumn I set aside four colonies to test with oxalic, early in November I was discussing this with a freind who said " are you sure there is no brood, as he thought that oxalic would kill it"so I went to look, three out of the four had brood in all stages, mostly only small patches, one colony had two whole combs of sealed brood plus two six inch patches of larvae.
QUESTION ONE. Will oxalic kill brood in any stage?
QUESTION TWO. How late, ambient temperature wise, could oxalic be used
Cheers  Andy Johnston

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