Beekeeper-led · Victoria

What is Varroa destructor?

The parasitic mite that’s reshaped beekeeping worldwide, now established in Victoria. What it is, what it does to a colony, and how to know if it’s there.

The short version

Varroa destructor is a parasitic mite that feeds on honeybees. It’s about the size of a pinhead, reddish-brown, and just visible to the naked eye — it looks like a tiny flat disc clinging to a bee’s body. It can’t live independently; it survives only on bees and inside their brood.

On its own, one mite is nothing. The problem is that varroa breeds fast, spreads through a colony, and carries viruses as it feeds — and left unchecked, it will kill a hive. It’s the single biggest threat to honeybees worldwide, and after being the last major beekeeping country without it, Australia now has it too.

What it does to a colony

The mite feeds on both adult bees and developing brood, mostly on the fat body — the organ bees rely on for immunity and overwintering. That feeding does two kinds of damage.

  • It weakens the bee directly. Bees that grow up with mites feeding on them emerge smaller, shorter-lived, and sometimes deformed — crumpled wings are a classic late sign.
  • It spreads viruses. As it feeds, the mite transmits viruses through the colony — deformed wing virus among them. It’s often the viruses, more than the feeding, that actually collapse the hive.

Because varroa breeds inside sealed brood cells, the mites you can see on adult bees are only a fraction of the ones in the hive. By the time damage is obvious, the load is usually already high. That’s why beekeepers monitor rather than wait for symptoms.

How the mite breeds

This is the part that makes varroa so hard to beat. A female mite slips into a brood cell just before the bees cap it, hides in the larval food, then lays her eggs on the developing bee. Her young feed and mature inside the sealed cell, protected from anything happening outside it, and emerge with the adult bee — already mated, ready to start again.

So the colony breeds bees and the mite breeds inside that same process, hidden. It’s why varroa can build quietly for a season and then overwhelm a hive, and why treatment timing matters so much.

How to tell if your bees have it

You can sometimes spot mites on adult bees, and deformed wings are a visible warning — but by the time you see either, the load is usually high. The only reliable way to know your actual mite level is to test for it, and the standard test is an alcohol wash: you take a sample of bees, wash the mites off, and count them against the number of bees.

That’s a whole method in itself, and we’ve written it up step by step: how to do a Varroa mite alcohol wash, including a free tool to record the result and check whether a treatment worked.

Varroa and Australia

Australia was the last major beekeeping nation to get varroa — for decades it stayed out while the rest of the world learned to live with it. That ended with a detection in Newcastle, New South Wales, in 2022. After an eradication attempt, the response moved to management, and the mite has since spread, reaching Victoria.

For Victorian beekeepers that changes the job. Varroa isn’t a distant threat any more; it’s a thing to monitor for and manage. If you find it for the first time, reporting is required by law — the Exotic Plant Pest Hotline is 1800 084 881.

Is honey from a treated hive safe?

Varroa affects bees, not people — the mite is specific to honeybees and poses no risk to humans or pets, and it doesn’t affect the honey. On our side, we monitor by alcohol wash and use only organic-approved methods if treatment is ever needed, never synthetic miticides, so there’s no chemical residue in our honey. It’s the same as it’s always been.

If you keep bees

The short version of what to do: monitor regularly, know your numbers, and act on them rather than on symptoms. Our Varroa surveillance hub is about exactly that — checking whether treatments are actually working, which matters more than ever now that resistance is turning up. And if you’re new to it and want to learn hands-on, that’s what our mentoring is for.

Every colony we keep was rescued, and we manage all of them this way. Every jar of our honey funds the next rescue.