Dee, what you are saying makes sense if you ignore the fact that in 
most cases both the bees and the pathogens are coming from all over the 
place which makes the kind of equilibrium that you are talking just about 
impossible to establish for most beekeepers, especially migratory 
beekeepers.  For example, in my case, although I am stationary, I notice a 
beekeeper that I do not know has moved some hives in at the bottom of the 
hill from me.  Until we get in contact with each other, neither one of us 
knows what problems we might be introducing to the other’s hives.  
     You keep bees in an area that has extremes of climate ( cold/hot but 
usually dry ). I live in an area that is temperate in climate but it is not 
particularly warm and it is known for being quite wet.  As Peter Borst has 
noted, it is unlikely that the bee that thrives in your area will do as 
well in my area.  I know you don’t think you are keeping AHB’s but I do 
know they are in your area so you must know that you will always be 
suspect.  Be that as it may, it is my understanding that AHB will probably 
not make it this far north because of the climate barrier.  If they do they 
will have to adapt to the point that they will be a lot different than the 
AHB that exists in your area.  But I will even go so far as to say that on 
this Island, Whidbey Island, Wa., if it weren’t for beekeepers and a non 
native blackberry, there would probably be no honeybees at all.  There is 
no agricultural source to speak of within twenty miles of here.  Even with 
the Himalayan blackberries which have pretty much taken over around here, 
and provide the only source of surplus honey as far as I have been able to 
tell, I am not sure there would be any feral bees if they weren’t 
continually being replenished by guys like me.
     So even though I always keep your goals in mind as an ideal target to 
shoot for, I feel treatment wise I have to be proactive at least to some 
degree in order to have bees at all.  I use formic acid as needed because 
it is naturally occuring in honey and it knocks down both varroa and 
trachael mites and possibly helps with nosema, although I have my doubts 
about the latter.  I treated my hives with formic late last summer and some 
of them seem to have had a nosema problem this unusually cold and wet 
spring.

Steve Noble   

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