In message <[log in to unmask]>, Joe Hemmens
<[log in to unmask]> writes
>> This gives an estimated total number of mites in the hive from the
>> actual number dropped in a 24 hour period.
>>
>> The table is based on the MAFF calulator distribtued to UK beekeepers.
>Natural mortality can vary by a factor of 3 from one week to
>another.  The Varroa calculator is calibrated in months.  In
>other words a colony might show a drop of say 2 per day
>averaged over 7 days yet the next week might show a drop of
>6 per day the very next week (within the same month).
>
>Either of these two factors alone would suggest that the
>Varroa Calculator is well nigh useless.
>
>Because of the data collected by DARG members (over 250,000
>mites were counted) it is possible to apply the Varroa
>Calculator retrospectively.  The results confirm my previous
>points.
Both these postings refer to the mite fall method which is stated as a
rough approximation and should be used as a guideline only for Mar/Apr
Sept/Oct (add 6 months for Antipodes). It was also developed for the bee
rhythm of the UK. The full use of the calculator requires you to
estimate varroa on adults, in worker cells and in drone cells from
samples of each. The samples are extrapolated to the whole colony. I
have to admit not using the thing as it is too complicated for me. Nor
have I checked it - I could compare the daily mite fall at its peak
before treating and then estimate the mite population after treatment.
Perhaps others would post their data - does the factor of 30 appear to
be right for May to August? or 100 for September?
--
James Kilty