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These are the notes from the presentation that I gave at the Auckland Bee Club on 11 Feb 2012 about how to count mites using a mesh or screened bottom board, hopefully others will also find these notes useful.
The amount of mites that are naturally falling out of your hive is a good indication of its mite population. A meshboard or a screened bottom board is a non intrusive way for Counting Mites without the need to open up the hive and disturb the bees.
This could done any time of the year, if you have a mesh board installed.
To start Counting Mites you will need:-
- A Kiwimana Meshboard
- Something Sticky for board (We use cooking Spray from the supermarket “Canola Oil”)
- An inspection tray to place under meshboard.
- A magnify glass can be handy for spotting mites
How often should I be Counting Mites?
Numbers of mites can expand quite rapidly in Autumn, so always be on the lookout for signs of mite damage. For example bees with deformed wing virus and or a large number of mites in drone cells.
We normally do a three-day count once a month. We keep a record of this and look for trends in the counts for that hive.
- Spray or apply sticky solution to inspection tray.
- Record time of day.
- Three days later as close to the same time of day tray was placed, remove tray.
- Count the mites on tray and divide them by 3, this give you the average fall per day. Doing it over multiple days gives you a more accurate count than doing a count of one day.
*** Don’t smoke or inspect your hive during the sample period, this will give you an inaccurate count ***
The mature mites are small, oval, and dark reddish-brown. Only count the mature mites.
Mites on tray after three days equals 30.
30 divided by 3 equals 10 mites per day
Record this figure in your hive records and work out the best course of action based on the following table:-
|Winter||Daily mite fall Greater than 0.5 mites per day. Colony collapse likely by end of season|
|Spring||Daily mite fall Greater than 6 mites per day. Colony collapse likely by end of season|
|Early summer||Daily mite fall Greater than 10 mites per day. Colony collapse likely by end of season|
|Mid-summer||Daily mite fall Greater than 16 mites per day. Colony collapse likely by end of season|
|Late summer||Daily mite fall Greater than 33 mites per day. Colony collapse likely by end of season|
|Autumn||Daily mite fall Greater than 20 mites per day. Colony collapse likely by end of season|
|Summer||Daily mite fall Greater than 8 mites per day. Begin treatment immediately|
|Summer||Daily mite fall 2 mites per day. Control needed within 2 months|
|Summer||Daily mite fall 1 mite per day. Control needed within 3 months, or before winter|
* Sourced from Control of Varroa MAF Book Page 46, which is available free HERE