Monitoring for varroa

Rigorously monitor Varroa levels and evaluate results

Routinely monitoring Varroa levels in a portion of your colonies in each apiary is critical to making good Varroa control decisions.

When to monitor

Where Varroa is not yet established, monitoring at least 4 times per year can be done by alcohol wash, soapy water wash, or sugar shake of 300 bees per colony using methods shown in the videos.

Where Varroa is established, monitoring is recommended once a month, except during chemical treatment and winter in very cold climates.

How to monitor

Use a standard 300-bee sampling method, so that you can compare mite loads over time, and make informed decisions about treatments.

How many hives to monitor

Beekeepers with only a few hives are best to monitor all their hives regularly. Beekeepers with many hives should regularly monitor a proportion of all their hives. Where beekeepers have greater than 10 hives per apiary and are only monitoring a portion of their hives 4 times per year, it is recommended to sample colonies both from the centre and outer edges of the apiary.

• Small apiary

  • Fewer than 10 colonies at an apiary = all colonies should be monitored for Varroa

• Medium to large apiary, multiple apiaries

  • Greater than 10 colonies per apiary = Sample 10 or more colonies in each apiary. If possible, include colonies from the centre as well as the outer edges of the apiary.

Varroa infestations will vary between colonies, even in the same apiary, so the more colonies that can be monitored, the greater accuracy you’ll have evaluating your mite levels. In the early years of Varroa establishment, where populations have not stabilised and re-infestation is common, sampling more than 10 colonies per apiary and rotating which colonies are monitored is highly recommended.

Evaluating mite numbers

The number of Varroa you find will depend on your location, how long Varroa has been established in the surrounding environment, the time of year, your previous Varroa IPM, and other situation specific considerations. When your colony needs chemical treatment depends on the brood rearing phase your colony is in and the number of Varroa you find in the results of your monitoring (i.e. alcohol wash, soapy water wash, sugar shake).

Quick mite infestation evaluation in the apiary

To simply evaluate Varroa infestation levels in the field, the beekeeper can count the number of mites detected per 300 worker bee sample and reference Table 2 control guidelines.

The following Varroa treatment thresholds (Table 2) were developed by the Honey Bee Health Coalition, a group of North American beekeepers, bee researchers, government agencies and other honey bee experts. Over time, Australian bee experts will develop specific Varroa treatment thresholds for Australia’s unique conditions, which may change the current recommendations.

Table 2. Treatment Thresholds by Colony Phase: Varroa % = # Varroa/100 adult bees (adapted from Honey Bee Health Coalition 2022 by E. Frost). In brackets (# mites found) is the total mites found in an alcohol wash, soapy water wash, or sugar shake of 300 worker bees.

Standard 300-bee sampling methods