Checking for Varroa Destructor – Preparing Hives for Winter:
It is most important that your bees start winter with low levels of varroa.
Although the queen will slow down laying or even stop in colder areas (meaning varroa levels will not increase over winter), as soon as it starts getting warmer in early spring the levels will surge dramatically as she starts laying again.
The Sugar Shake method is the most effective way to check varroa levels:
- Place 1/2 a cup (approximately 300 bees) in a sugar shake jar*
- Add 2 Tablespoons of icing sugar
- Shake to ensure the bees are properly coated
- Leave for up to 5 minutes
- Tip the jar upside down to remove any varroa that have become dislodged by the icing sugar and count them.
- Return bees to the hive.
Sugar shake jar
A 3% count is considered acceptable i.e. 9 varroa to 300 bees. If more than 40 varroa are present, you are in serious danger of losing your hive and need to re-treat urgently. It is advisable in any case to re-treat if you have more than 3% before leaving them for winter.
Oxalic acid treatment with vapor is a good way to treat at this time of year as you do not need to open the hive to treat them. Be sure you follow the prescribed timing or you will not be successful – every 5 days for 2 weeks. https://www.hiveworld.co.nz/product/vapmite-oxalic-acid-vaporiser/
* It is easy to make your own Sugar Shaker using a half-size Agee jar or similar with a cut out metal screw lid to hold the mesh. This needs to be of a size to allow varroa through but not the bees. Metal, nylon or plastic are ideal materials for your strainer mesh.
More information on varroa can be found in this blog: