Bee Mites

Mites are today the biggest group of problems in beekeeping, and varroa, the single biggest cause of colony losses, belongs to this group. There are three harmful mites the beekeeper needs to know: the ubiquitous Varroa destructor, Tropilaelaps, a notifiable exotic species, and the microscopic tracheal mite. Control is based on regular measurement, timely intervention and measuring the result again.

Mites in the group

Why are they so destructive?

The original hosts of varroa and Tropilaelaps are the honey bee species of Asia. These bees share a long history with the mites and have developed defences such as grooming and hygienic behaviour. Because our honey bee (Apis mellifera) lacks this history, the mite multiplies unchecked.

The real damage comes less from feeding than from virus transmission. The mite transmits viruses such as deformed wing virus directly into the bee's body; this is why a colony can collapse even before mite numbers look very high. The mite also feeds on the bee's fat body, shortening the life of winter bees in particular.

How varroa differs from Tropilaelaps

• Shape: Varroa is wide, like a crab shell; Tropilaelaps is long and narrow.
• Movement: Varroa moves slowly; Tropilaelaps runs quickly over the comb.
• Where: Varroa can live on adult bees for weeks; Tropilaelaps cannot feed on adult bees and dies within a few days when there is no brood.
• Monitoring: A sugar roll and an alcohol wash give a numerical result for varroa but often fail to catch Tropilaelaps. For Tropilaelaps, brood cells are uncapped and the frame is knocked onto a tray (bump test).

A clean sugar roll is not proof that Tropilaelaps is absent. This mite, widespread in Asia, has recently also been reported from the Caucasus; the risk for Türkiye is therefore increasing.

Tracheal mite

The tracheal mite enters the breathing tubes in the thorax of young bees, multiplies there and feeds on the bee's haemolymph. The breathing tubes become stained and darkened. Flightless bees with their wings held apart in a "K" shape may be seen, but this sign is not specific; it also occurs with nosema and viruses. The diagnosis is made by opening the bee's thorax and using a magnifying glass or microscope. Because bee populations have gained resistance over time and some products used against varroa also suppress this mite, its importance has declined in many regions.

The basis of control

1. Measure: Do a sugar roll or alcohol wash with about 300 bees (roughly half a glass) taken from a brood frame; calculate the number of mites per 100 bees. A natural mite drop tray and uncapping drone brood also provide guidance.
2. Use non-chemical methods: drone brood removal, brood breaks, splitting and caging the queen reduce the mite load.
3. Use an authorised product if necessary: follow its label, do not apply it while supers are on, and rotate the groups of active substances.
4. Measure the result: if the expected drop has not occurred, consider resistance or incorrect application and carry out a second treatment before winter.

Detailed methods are on the Varroa and Amitraz Treatment pages.

Varroa calendar

The mite level in late summer largely determines how many colonies will survive to spring.