I collected one colony from a house a while ago that had loads of varroa. (The first varroa infested feral colony for me ever.) I gave them a virgin queen from my 'preferred stock.' At this point the colony's brood has emerged and the new queen started laying several days ago. I do see varroa on the adult bees and would like to knock them down with oxalic acid. I understand that varroa will dive under larvae just prior to cells being capped. The oldest larvae in this colony has maybe 3- or 4 days old so it seems that all the varroa will be exposed to the OA. Is there any risk from the OA treatment to open brood or very young laying queens? Thanks. Waldemar Long Island, NY -- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---