VARROA
Varroa destructor (yes, it does sound like a Marvel baddie!) is a pesky little mite that latches onto bees, sucking on their bee-goodness, transmitting viruses and leaving weakened bees susceptible to infection.
Arriving in New Zealand around twenty years ago, varroa has found our honeybees defenseless against it. This has led to huge losses of feral colonies and has had a massive impact on the beekeeping industry. While tiny, these little suckers can be seen in the hive clinging to bees or scuttling across brood comb. In fact, if you scaled up a mite on a bee to human proportions it would be like you carrying around a blood sucking rabbit! (Don’t spend too much time thinking about that …)
​
Varroa mites pass from bee to bee. A new host bee then returns to it’s hive with the stowaway on board. In the hive the mite ducks into the cell of a developing larvae. Once the cell is capped, the mite lays eggs which hatch and feed on the developing bee. The varroa lays a male offspring and four or five females which can mature and mate before emerging from the cell. This gives them a 15 day life cycle which allows them to spread through the hive rapidly.
Finding varroa in the hive can be tricky since they are often lurking below the cell caps, but once emerged their red/brown crablike appearance stands out against the newly hatched pale bees. When looking for varroa, breaking open drone comb and pulling out the white larvae will clearly show if mites are present.
A ‘sticky board’ (or white card smeared with vegetable oil) on the floor of the hive will show any mites that have been groomed off and fallen to the floor, this is often used in combination with varroa treatments to slow their efficacy or the level of infestation.
Sugar shakes and alcohol shakes can also be used to assess varroa in a hive, although these methods involve terminal damage to the sample of bees used, so if your hive is already weak you may wish to avoid these methods.
​
There are many ways to treat varroa mites, with new products and methods being developed all the time. Worthy of another ‘rough guide’ really … watch this space …
