In article <[log in to unmask]>, JamesCBach <[log in to unmask]> writes > But remember that, as with all diseases, and conditions of colonies >you don't know whether the bees have Nosema, or other organism, unless you >do some laboratory work. I agree, but in a practical world, where we have 1700 hives, and two people to do them all, finding the time to do lab work just detracts from getting on with the job. There are others on this list with far more colonies to get through than us, so the sheer logistics of the suggestion that they should all be sampled and tested (even at an outside lab) is not practicable. > Observations may suggest that the "condition" of a >colony(s) is not as it should be, but defining the condition or identifying >the malady can only be done by the laboratory. We always, at a commercial level, have to play the odds rather than going for complete certainty. We have 50 years experience of seeing the effects of nosema, and although we won't be right every time we get a pretty good idea of what is going on just by observation. >Conjecture costs the beekeeping industry >hundreds of thousands of dollars each year in the US because the business >decision was not based upon laboratory work Unless you value your time at a very low level, and are able to do your tests yourself, which is admittedly a possibility at a smaller scale level, the cost of a lab test is many times more than the cost of a fumidil treatment. If you know the vulnerability of certain colonies due to stress etc, and that a high proportion of them will exhibit some degree of nosema symptoms, then a prophylactic treatment is prudent and economically sound. Perhaps, for arguments sake, say 50% turned out not to need it in lab tests, you will have saved the cost of treating 50% of them, but added the cost of treating 100% of them. Thus I would probably argue that this conjecture, which is only valid if based on experience and/or good research, actually SAVES a lot of money. Once again though, I am NOT arguing for universal annual prophylactic treatment. Only where a definite risk pattern is established should it be applied to all colonies subject to these circumstances. Another situation could be where you have noted a rising trend of nosema related symptoms occurring in your colonies, because waiting until you have a serious outbreak proven by testing is, at least economically, way way too late. One round of treatment applied at the correct time can tidy you up for seasons to come. Sometimes you will get it wrong, but in a small minority of cases. The colony which does not have nosema, but is in a high risk group, will not be harmed by treatment. Occasionally your symptoms may be the result of something else stressing the colony, such as tracheal mites or queen problems, although nowadays colonies failing from tracheal (acarine) mites is relatively rare here. In those cases you wasted the treatment and the colony will still fail, when an alternative measure may have succeeded. Once again, though, this brings us back to commercial reality, where this minority that are not right are just accepted to be write-offs which will die( that could start a few flames!). Of course, you do not know which ones they are until they are dead in spring. There is just no economic sense in testing everything exhaustively to look for a few colonies which do not fit into the pattern your experience or knowledge dictate. In the case of the few colonies suffering tracheal mite related symptoms, saving them, especially in a situation where the vast majority of the colonies are mite tolerant, just perpetuates the problem. >You might read my article in the November 1999 Gleanings on Page 34 for >additional studies in Washington State. I don't get Gleanings. I used to back in the 80's, but currently the only US journal I subscribe to is ABJ. Is there an on line version I can go to look at? Kind regards to all Murray -- Murray McGregor