Agriculture Reference
In-Depth Information
onto the hive's floor. These can be purchased from most bee-supply shops. The fallen
mites adhere to this board. After 24 hours, count the mites on the board. Depending on
whether you are in the Northern or Southern Hemisphere, if your count is 6 mites in
May/November; 10 mites in June/December; 16 mites in July/January; and 33 mites
in August/February (or below) your colony is running along fine, but keep a close eye
on it. If the count is in excess of these figures, the colony will collapse before the end of
the season.
Sampling the whole hive for varroa numbers
Normally, only about 15% of the mites will be on the adult bees in a hive in full
production. A correction factor is therefore needed to account for the rest:
Using a clean, sticky board as above, place Apistan or Bayvarol in the hive to kill the
mites (see ' Treating Varroa destructor' below).
After 24 hours count the mites. Assume an 85% kill rate.
Divide number of mites counted by 0.85.
If the hive is in full production, multiply the result by 6.
If the hive is not in full production but has brood, multiply it by 3.
If no brood is present, then no correction factor is required.
This method should give you an idea of the total number of mites in a hive. A rule of
thumb for working out the approximate total number of mites in a colony is, however,
as follows:
November-February (May-August): multiply the daily mite fall on the sticky
board by 400.
March-April (September-October) and September-October (March-April):
Multiply the daily mite fall by 100.
May-August (November-February): Multiply the daily mite fall by 30.
