Randy Oliver article on Nosema in Jan 2012 ABJ

Discussion in 'Bee News' started by ski, Jan 11, 2012.

  1. ski

    ski New Member

    Likes Received:
    Trophy Points:
    For those that do not get or have time to read the bee magazines I thought I would list a few points that I thought were interesting in an article by Randy Oliver on Nosema in the January 2012 issue of the American Bee Journal.

    Sick Bees part 15
    American Bee Journal January 2012
    Sick Bees by Randy Oliver

    Interesting note - Young bees do consume pollen.

    Randy Oliver questions weather spore counts can be translated into meaningful treatment thresholds because in a 50 bee sample a few highly infected bees skewed the spore count to an alarming level. This would be even worse in a 10 bee sample if one infected bee was included.
    What may be a better way is to look at the infection rate of bees rather then an average spore count. It appears that the tip point for colony health occurs when more then about 40% of the bees in the hive become infected (a 40% infection rate). – It may be more important to determine the relative proportion of infected bees to healthy bees.

    It appears that in order to make a decision whether to treat or not, that a couple of 5-bee samples should be adequate, interpreted as follows:

    Zero infected bees in each sample – safe!
    1 Positive bee in each sample – probably safe.
    2 Positive bees in each sample - probably should treat.
    3 Or more bees in each sample – that hive is in trouble.

    What could be simpler than that?

    The article continues to read as follows:
    One huge assumption
    All of these probabilities are contingent upon your taking a representative sample that reflects the overall infection rate of the hive. Would this be the case in real life? Would 5-bee samples give consistent results? I didn’t know, so I decided to put it to the test.

    ……I took samples of bees from the weakest hives in each yard, and later processed subsamples of 5 bees at a time.

    The article reads:
    Pratical application: I found the above a reality check instructive to say the least! In fact I could say that I learned more about the degree of Nosema infection in my operation in 3 hours of bee squashing then I’d learned in the last 4 years of counting spores! I doubt that I will ever do another spore count.

    The article reads:
    I love this method! For one. I learned that Nosema was only associated with half of my weakest hives, so I can now sleep a bit better. On the other hand, half of those weak hives did have high Nosema levels, so I need to address this (spot treatment?). I am now eager to go sample some strong colonies. What is also apparent is that the method worked remarkably well! Its not perfect, but it appears that I’d rarely miss an infection if I processed two samples of 5 bees for each tested hive. And the method readily picked out the really sick hive! Clearly this is only a preliminary test of the procedure, and needs to be repeated with a lot more hives, but the apparent accuracy of the method is very encouraging to me.

    The article concludes:
    The only remaining problem is that most beekeepers will choke at the thought of how much time it would take them to squash and microscopically view 10 bees out of each hive. And that leads us to: A neat Little Shortcut (to be concluded in the February 2012 issue)

    Note – There is a lot more to this article and is very interesting to read, I just hit some of the high points. It reads like a great who done it novel. I can’t wait until February.
  2. tecumseh

    tecumseh New Member

    Likes Received:
    Trophy Points:
    thanks ski for including this...

    recently I found a number of mr oliver's article to be especially informative.... his current focus on nosema is especially though provoking since he has now shed light on how 'spore count' may be extremely misleading. I look forward to his 'short cut' in next month's edition. I also like Mr Oliver's format in that he present some information and then does a highlight of what the practical implication are of this information.

    a snip..
    'Would this be the case in real life? Would 5-bee samples give consistent results? I didn’t know, so I decided to put it to the test.'

    with some experience and the information as to where to take bee samples from then yes a 5 bee sample would be sufficient. if you were lacking this information or did not have the experience in taking sample then 10 bees (as the article in question also suggested) would be a much more reliable sample size.

    there is quite a good deal of basic information in the study of statistic in regards to taking an adequate 'sample size' to adequately represent 'the population'. in almost all cases the number 30 will get you a high degree of accurate and reliable statistical number(s) to apply to the population.