> 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 Rudd Ruary That is why I said that I would take blackened trachaea as a positive indicator of an acarine infestation, not that I would take non-discoloured trachaea as an indicator that there was no infestation at all. But is this not true for most diseases, whether we are talking about bees or any other organism? Many pathogens can be present in such small numbers that they are not apparent - a few dozen varroa, a few hundred AFB or EFB bacteria - and in most cases are not worth worrying about. In the case of acarine, I have now given up sampling or treating for it because we just do not have a problem - I think that lack of treatment caused the susceptible colonies to die out and the stock that we now have is able to cope most of the time; however, I have no doubt that there are some mites in some of my bees. Now all we have to do is achieve the same balance with varroa! Peter Edwards [log in to unmask] :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::