Bill, Nasr and all others commenting on this perennial problem, Comments arising from the suggestion trying to introduce some organisation into the periods when V.d. is treated reflect the simplistic manner in which I put my suggestions on to the list. Bill is quite right to emphasis the problems of diverse geography etc. To clarify this matter: I am not advocating that the whole of the Americas, E.U. etc. treat at the same time. What I am advocating is that at local level (County, Department, Parish, group, Association) or at what would be deemed possible, there be measures put into place where neighbouring beekeepers treat within an agreed period. This would have to take into account such matters as local geomorphology, spatial distribution of hives, normal weather patterns and other restrictions to practice. At least in areas that were able to implicate this order, the chance of rapid re-infestation of mites would be greatly limited. Problems would still occur in boundary areas adjacent to regions having other applied practices. This, it seems to me would be no worse than what is happening at the present. Spend monies on treatment material and giving time to its application - only then having the greater benefit ruled to level not much above zero due to a neighbour treating at another time. Regarding enforcement - Nobody likes being told what to do and when to do it! - But if it is explained that what you as an individual are doing will be helping yourself and others - where is the logic in disagreement! Resistance: A mite that has been dosed in one hive, moved to another as a colony breaks down or just by drifting (what ever the transfer mode) then dosed again at a level not conducive to proper control - will not this also aid development of resistance? If it was explained that non participation would eventually result in your own hives getting into trouble - most individuals would concede! I agree, there are always a few that will not co-operate. Hence, the suggestion of controlled supply and return of used strips in the case of Apistan, Checkmite. This will also limit unintended / accidental pollution by pesticides and PVC plastics (latter adding to Acid Rainfall amounts). As a group of individuals, we are good at forming groups for this, that and the other - why not medication practice. (Medhat - organised dipping of sheep was practiced in U.K. to control SCAB, caused by a mite! - but agree, bees have no wool). Returning to Formic Acid treatment and Queen loss - appreciating the the circumstances are different, Formic Acid fumigation in winter buildings appears to increase queen mortality rates - whilst appearing to be able to control V.d. (investigation underway by Dr. Rob Currie/Robyn Underwood at Univ. of Manitoba. Canada). This type of mite control presumably is of interest to those under pressure from climatic conditions, such as Maria in Peace River area, Alberta. If this type of treatment becomes possible - then what! A certain % of beekeepers treating at the end of the season outdoors, whilst others wait for a treatment indoors. - All in the name of control. There is going to be a wide difference in mite populations in these hives. Please remember that (tongue in cheek!) I am beekeeping here in France, well renowned for perfect order and organisation. Peter. Indre, France.