Ruary said:
You should be careful in giving a diagnosis of non infestation if the
trachea is not discoloured under x10 magnification. I dissected a bee and
under x10 the trachea looked clear. I dissected the trachea out to mount and
under X40 found a mite lurking in it.

Ruary is right as only in a somewhat heavy & late stage infestation does the
trachea become blackened (I once quit counting TM at around 200 TM in a
single bee). Early and recent infestation could be missed if not confirmed
by microscope.

 I will say *as Peter pointed out* that when I have  seen the blackened
trachea I have always found tracheal mites when confirmed at home with the
microscope. I also believe that if I looked at enough samples of most
peoples bees I would find a TM lurking in a few of the samples. Why TM
levels rise and fall I do not fully understand. Ideas from the list?

If Peter had said in his original post that he suspected a heavy TM
infestation when he saw the  *abnormal* blackened trachea I would have
remained silent.

 I was pretty sure of what Peter meant but thought the point needed
clarification for the list.

Bob

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