Hello Lloyd and All,
Lloyd wrote:
My suggestion is to not treat for Tracheal Mites and to instead "take your losses", and make your small contribution to developing wide-spread resistance.
I would not recommend this method if keeping  Italian bees.  Carniolans have long shown a tracheal mite tolerance but Italians have shown a weakness. 

 I check bees on a regular basis for others and many times the problems  the beekeeper is having is tracheal mites when trying to run italian bees without any TM treatment.
Lloyd wrote:
My own 100+ colonies have not been treated for Tracheal Mites in many years.  Every year I know I lose some to the effects of Tracheal infestation, but I consider that a price paid along the way to wide-spread resistance.  I mourn the losses, but at fewer than 20% of my hives, they are certainly at an acceptable level and are quickly replaced by splits.
I have heard the above before many times.   It takes a few years but eventually the infestation level will climb.  Proper testing is the only way you can be sure TM levels are not approaching high levels. For reasons I do not understand myself bees can stay at a 10% or less infestation rate year after year and then one year reach levels over the winter in which the hives can not be saved. You simply find a  small softball cluster of bees  and most clusters for some unknown reason to me are queenright 
 The hive will be full of honey and pollen in most cases.  I have tried to save a few of these hives but to no avail.  Adding brood and bees only buys time as the infestation is overwhelming.  Maybe others on the list will comment but the above is what I have seen. 
Not meant to be a putdown of Richard Taylor and as a reader of his monthly column  Richard recommended for years no need to treat for Nosema. Those on the list which have read his column for years know what I am saying.
A couple years ago Richard almost lost all his bees and the problem was nosema . Richard did not try to hide the reason his bees died but told things as they were. My kind of beekeeper.!  I usually find nosema in samples of bees which have not had any fumidil-B in a couple years. Nosema can stay at low levels when not treating as Richard said but for reasons unknown to me the nosema can quickly reach high levels over a winter. 

Nosema is easily tested for without a glass . For years ads in bee magazines showed the method. Simply take the worker bee and hold the head down on a flat surface. Take your finger nail and place right above the stinger and spread the bee apart exposing the mid gut. Slightly brown (not white)  and not swollen is ok.    White and swollen indicates nosema.  I have NEVER had a case I diagnosed in the field for nosema not be nosema when put under the microscope. I had a beekeeper once which brought about 200 bees. Each bee of 200 had a swollen white mid gut. He thought I was pulling his leg until I went outside to one of my hives and grabbed a couple of nosema free bees to dissect and show him. Sincerely,
Bob Harrison
Ps . My computer has been putting out posts with equal marks.   Thanks to All which have sent remidies.    I tried all of them to no avail.        My computer guru will be back in town in a week or two so maybe we can get things straightened out.   Thanks to the moderators  for running my posts as I would have to remain silent otherwise until fixed.    Sorry for any  inconvience.    If my posts quit coming you will  know the moderators have quit running my posts and I will be back when my posts are correct.