To all who like a little history and believe in fair play, even for the
tracheal mite.   
Having stirred up quite a thread because of my remarks about the mite I
thought its history might be worth recounting.  In the English Channel,
just off the coast of southern England, lies a small island, the Isle of
Wight.  In 1904 some of its bees started to sicken and die.  This sickness
spread until almost all the bees in the island were wiped out.  As was to 
be expected it crossed the narrow strip of water and appeared in nearby
England and slowly spread over the whole country, creating havoc and wiping
out whole apiaries It naturally took on the name of the Isle of Wight
Disease.  The experts were called in but could find no answer.  In
desperation beekeepers tried all manner of treatments to no avail until in
1919 a researcher chanced to look at the main tracheae and found the mites.
 Problem solved.  We have a new disease.  The mite was christened Acarapis
Woodi ( a Mr Wood had financed the researcher who found the mite) and
Acarine disease was established.  Incidentally I was two years old at the 
time so did not take notice until much later.  Two of the obvious signs of
this disease were mass crawling and dislocated wings so these signs went
into all the text books as due to the mites.  
As soon as the discovery of the mites was broadcast they were found in
Switzerland, France and Czecho-Slovakia.  Later on they were found all over
Europe, Russia, Africa and South America.  The obvious conclusion was that
the mite had been around all the time just waiting to be discovered.
A humble beekeeper (my hazy memory tells me he was a railway employee) a Mr
Frow, came forward with a cure composed in part of petrol (gasoline) and
benzene, whose fumes killed the mites but unfortunately killed any open
brood and lots of the older bees so sometimes it did more harm than good.  
Then Oil of Wintergreen came along and became the standard treatment.  Most
beekeepers had no microscope so treatment became routine, whether the mites
were present or not.
Sometime after the second world war along came Folbex and then Folbex VA, 
more toxic smokes.  They were found to leave undesirable residues in the
beeswax and were withdrawn from the market.  Since then there has been no 
legal treatment and gradually beekeepers stopped worrying about it.   
Around the sixties research showed that crawling and dislocated wings had 
nothing to do with the mites but was due to viruses. To date some twenty
viruses have been found in honey bees around the world.  Apparently
Arkansas has its own special brand (see Morse).  For most of the time these
lie dormant but wake up and take over if the bees are stressed.  Moreover 
our leading bee pathologist found that colonies with a high level of mite 
infestation could thrive and produce surplus honey and that bees with mites
in both tracheae could fly and forage quite happily.  The only direct
effect of the mites was a slight shortening of life.  It was decided that 
any sickness was an indirect result  in that  mite bites allowed bacteria 
to enter the  blood and thus poison the bee.
The main source of trouble from acarine arises when the stock goes into
winter heavily infested.  If we have a situation in the spring where the
new brood is delayed due to weather, poor queen, lack of pollen, etc.the
old bees will be dying off and the death rate may be greater than the birth
rate and the stock dwindles and dies.  Short of checking by dissectiion or
blanket treatment of all colonies in early autumn whilst still breeding I 
do not see how anyone can anticipate this.
        IMHO and certainly in the opinion of researchers the danger of
tracheal mites is overrated.  You can only be sure of  their presence by
dissection so without that it is pointless to treat.  I think its effect on
a healthy colony is minimal.  If the colony is sick do not immediately
blame acarine.  Look for trouble elsewhere. AFB, EFB, CPV, APV, Nosema,
Dysentery, to name the most likely ones, are all waiting in the wings The 
first book on every beekeepers bookshelf should be one on bee diseases and
their recognition.                                       
 
For the sake of any beginners reading this I must emphasise that the above
has nothing whatever to do with that other well known mite, Varroa.  That 
needs careful treatment.  It was first found in England in 1992, spread
rapidly through the southern counties and in 94-95 wiped out some 5o% of
the colonies. It now covers the country.  I think we have it under control
although it is still early days.  Thanks to a European directive the only 
legal treatment is now Bayvarol (a close relative of Apistan)  We have just
received a warning that resistance to Apistan has now spread from Italy
across Europe to parts of France.  How soon before it jumps the Channel?    
                Sid P.