In article <[log in to unmask]>, Alan Riach <[log in to unmask]> writes >Disease control by colony destruction has certain advantages since it >will destroy "disease susceptable genes" as well as the disease itself. We in Scotland are very fortunate to have a very low indeed incidence of AFB, and a low rate of EFB. I have always been under the impression that AFB and EFB are present at low, usually non symptomatic, levels in all, or nearly all, of our colonies. We have never had a single case of AFB in 50 years in bees, totalling some 30,000 plus hive/seasons. This is without burning, AND with the importation of stock from countries where AFB is a persistent and serious problem, so we must have, at some stage, imported some supposedly genetically susceptible stock. An old bee inspector and national authority who was involved in several destruction episodes (actually he recorded several dozen over the years) kept records going back to before the last war, up to the mid 80's. He told me that the incidence of AFB in Scotland was little different in his latter years than in his early years, and in the records of his predecessor. This is despite there being considerable experimentation undertaken in the field in the 60's and 70's from an inspector based in Aberdeen with treatment rather than destruction. There appeared to be not much to choose between the two strategies in terms of re-appearance of the problem. As the incidence of this is rare in Scotland we may actually have several linked phenomena at work here, although I reckon environmental factors , linked to SOME genetic predisposition to resistance, are the main factors at play here. The old expert I was referring to kept a map of the whole area (about 4000 square miles) on his office wall, and there were coloured pins in it for every recorded AFB outbreak over the last 70 or so years. It was particularly noticeable that it occurred in pockets, with large tracts of the area with no recorded outbreaks ever, and others with 10 or more over the period. One small area in particular, about 5 miles long in a river valley had nearly 20 incidents in 70 years. I have heard in the last year of yet another outbreak affecting this place. Certainly, if genetics were the sole factor, as a result of a destruction policy, we could (should?) have encountered AFB in our imported stock. Yet we have not. We are not *especially* careful about hygeine, move boxes incessantly from hive to hive, and mix colonies from different apiaries. We have bought bees from people who have relatively recently (in the previous 5 years) suffered from AFB somewhere in their unit. EFB is certainly different, and you can cause the stress that triggers the appearance of symptoms by careless management. Having done this, and learned from the experience, we treat our bees reasonably well and have not seen any EFB like symptoms for several years (and never destroyed a single colony). I am quite certain EFB at least is endemic and will only rear its head when conditions favour it, subsiding again when the stress is removed although some treatment may be needed to help it along. Thus I seriously doubt if destruction for EFB has anything other than a superficial argument for it, as it will not tackle in any way the underlying presence of the problem. AFB? Well, I do not really know. If I found one I would burn it (out of fear of the problem), but in the light of the experiences of others I am not sure if that is strictly necessary, or even if it is an effective strategy. We have low AFB and we have a burning strategy so for the time being I will go along with it, even if the reasons for the low AFB may be coincidental. -- Murray McGregor