Robin Dartington said: When all else fails, we will have dusts and powders ...fine dusts can probably still help when varooa has become resistant to all other chemicals in use today. Two points: First, how will you stop these 'dusts' from contaminating your honey. Dust will stick to any honey in open cells and we know that honey is moved from brood chamber to supers. Even icing sugar contains anti-caking agents. As far as I can see, powdered plain sugar would be the least unacceptable dust. Second, it is my understanding that it is very unlikely that varroa will ever become resistant to substances like thymol or organic acids. Peter Edwards [log in to unmask] www.stratford-upon-avon.freeserve.co.uk/ :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::