71. What is the Varroa mite, and how dangerous is it?

If you spend any time around beekeepers, you will quickly hear about the Varroa mite. It is often described as the most serious threat to honeybee colonies worldwide. For a beginner, that can sound alarming—but understanding it clearly is the first step to managing it calmly and effectively.

Let’s take a closer look at what it is, what it does, and why it matters.

What is the Varroa mite?

The Varroa mite (Varroa destructor) is a tiny, reddish-brown parasite that attacks honeybees. It is about the size of a sesame seed, so just visible to the naked eye if you look closely.

These mites attach themselves to adult bees and developing brood (baby bees). They feed on the bee’s body fluids, weakening the bee over time.

You might spot them as small oval dots on a bee’s back or between its body segments. However, many mites are hidden inside brood cells, where they reproduce out of sight.

How do Varroa mites affect bees?

Varroa mites harm bees in two main ways.

First, they feed on the bee, which weakens both adult bees and developing brood. A bee that has been parasitised may be smaller, weaker, or have deformed wings.

Second, and more seriously, Varroa mites spread viruses. One of the most common is the Deformed Wing Virus (DWV), which causes bees to emerge with shrivelled, unusable wings.

A healthy bee colony can tolerate small stresses, but when mites and viruses combine, the colony can quickly decline.

How fast do they spread?

One of the reasons Varroa mites are so dangerous is how quickly they multiply.

A female mite enters a brood cell just before it is capped. Inside, she lays several eggs. When the young bee emerges, new mites emerge with it, ready to spread further.

This means mite numbers can grow quietly for weeks or months before you notice a problem. By the time symptoms appear, the infestation may already be severe.

How dangerous are Varroa mites?

In simple terms, very dangerous if left unmanaged.

Without treatment or monitoring, a Varroa infestation can destroy a colony within one to two years. In some cases, especially in colder climates or weaker colonies, collapse can happen even faster.

Common signs of a serious infestation include:

• Bees with deformed wings

• Patchy or unhealthy brood patterns

• A sudden drop in bee population

• Bees crawling near the hive entrance, unable to fly

However, it’s important to remember this: Varroa mites are manageable. Many beekeepers successfully keep healthy colonies by monitoring and treating mites regularly.

How do mites spread between hives?

Varroa mites do not stay in one place.

They spread through:

• Drifting bees (bees entering the wrong hive)

• Robbing behaviour (bees stealing honey from weak colonies)

• Swarming

• Movement of hives by beekeepers

This means even if you start with healthy bees, mites can still arrive from nearby colonies.

What can a beginner do?

The key is not to panic, but to stay aware and proactive.

Here are a few simple steps:

1. Learn to monitor mite levelsMethods like sugar shake or sticky boards help you estimate how many mites are present.

2. Check regularlyDuring the active season, checking every few weeks helps you spot problems early.

3. Use appropriate treatmentsThere are several options, including organic acids (like oxalic acid) and other approved treatments. Choose one suitable for your climate and follow instructions carefully.

4. Keep strong coloniesHealthy, well-fed colonies cope better with stress and recover more quickly.

A reassuring thought

Nearly every beekeeper faces Varroa mites—it is simply part of modern beekeeping. While they are a serious threat, they are not a reason to give up.

With a little knowledge and regular attention, you can manage them successfully and keep your bees thriving.

Think of Varroa not as an enemy to fear, but as something to watch, understand, and control—just like any other aspect of caring for your hive.