Varroa Tester CO₂ (Classic)

01 · YOU SUPPLY THE DENOMINATOR

What decides whether the number is any use

The method is simple: a sample of bees off a brood frame, 5-6 seconds of CO₂, 10 seconds of gentle shaking, and the mites fall through the screen to the bottom. Between 10 and 20 seconds later the bees come round.

But the result is a percentage, and that needs two numbers. The device gives you one; the other is how many bees you put in. Mark the level on the jar and always use the same one, because counting 6 mites does not mean the same thing with 150 bees as with 300.

02 · SIX MITES IN TWO HUNDRED BEES

The sum and the threshold

You divide the number of mites by 2 if the sample is 200 bees, or by 3 if it is 300. So 6 mites in 200 bees is 3 %.

3 % in summer is the threshold generally used to treat without waiting. And as wintering approaches the bar drops: the same figure that is tolerable in July is not in September, because the mites that go into winter go in on the very bees that have to carry the colony through it.

03 · MIND THE QUEEN

The warning that has to be given

The sample comes off a frame of sealed brood, which is where the nurse bees are and where the mite concentrates. But that is also where the queen usually is.

Before you shake, find her or pick a frame she is not on. A non-lethal method stops being one if the queen ends up in the jar.

04 · 16 G THREADED CARTRIDGES

Not just any will do

It runs on 16 g CO₂ cartridges WITH A THREAD, the same ones used in cycling or airsoft. They are not included and have to be bought separately.

Watch for this when restocking: plain unthreaded cartridges will not work even at the same weight. And the gas goes in at the lid, never squirted straight onto the bees.

05 · DON'T MIX METHODS

What informs you is the series

The alcohol wash is still the reference method because it destroys the sample and takes everything with it. CO₂ gives you the bees back alive, which is its real advantage in small nucs or in lines you are selecting.

What you should not do is alternate: if one check is alcohol, the next sugar and the next CO₂, the numbers cannot be compared. Pick one and repeat it in spring, summer and autumn — what teaches you something is the trend.

06 · BEFORE YOU BUY

This is the device: