Varroa mite is a parasite that feeds on honey bees and reproduces within the bee hive.
Varroa was detected on mainland Australia at the Port of Newcastle, NSW in June 2022, triggering the Varroa Mite Emergency Response in an attempt to eradicate this significant bee pest, eradication was not successful.
From September 2023 it was decided Australia would transition to managing Varroa mite, a decision endorsed by the Consultative Committee on Emergency Plant Pests and agreed by the National Management Group.
Currently, Varroa is established in limited 'Management Zones' within NSW where beekeepers must regularly monitor for Varroa and keep its levels under control in their hives to prevent hive death.
The treatment threshold guide in this article is part of a larger NSW Department of Primary Industries factsheet titled Varroa mite management options for NSW.
Failure to reduce Varroa numbers below a damaging threshold will weaken the hive, making it more susceptible to pesticides, viruses, and other stressors and reduce its ability to produce honey and pollinate crops.
Without timely and appropriate Varroa control, infested colonies will steadily weaken and die.
Where Varroa is newly established, large numbers of feral colonies and neglected registered and unregistered colonies are a major source of mite invasion into actively managed colonies.
This invasion results in rapid increases in mite numbers in managed colonies, making monitoring mite levels across all apiaries a minimum of four times a year with alcohol wash, soapy water wash, or sugar shake monitoring methods critical.
Varroa treatment thresholds depend on the hive development phase/season and the number of Varroa found per hive in an alcohol wash, soapy water wash, or sugar shake.
The following guidelines are adapted from the NSW DPI factsheet Varroa mite management options for NSW.
Dormant hive phase (broodless period)
- Less than three mites in alcohol wash - wait - no control needed yet
- Three to five mites in wash - urgent - control immediately
Population increase hive phase (typically spring)
- Less than six mites in alcohol wash - wait - no control needed yet
- Six to nine mites in wash - urgent - control immediately
Peak population (typically summer)
- Less than six mites in alcohol wash - wait - no control needed yet
- Nine-plus mites in wash - urgent - control immediately
Population decrease (typically autumn)
- Less than six mites in alcohol wash - wait - no control needed yet.
- Six to nine-plus mites in wash - urgent - control immediately.
Hear from the experts
The free online 44th Tocal Beekeepers' Field Day is Varroa focused this year.
To learn more about what specific treatments and controls are available for Varroa and how beekeepers can continue to keep bees with Varroa, tune into the field day online this Saturday October 21 from 9am to 12pm.
Topics covered will include:
- Nutrition of honey bees and Varroa mites.
- The ins and outs of monitoring for Varroa
- Varroa management options for NSW beekeepers
- Varroa, viruses and biosecurity risk. Ferals, unmanaged and surveillance hives
- Papua New Guinea, Fiji Varroa experiences and effects on pollination
Speakers include Southern Cross University lecturer and leader of Bees for Sustainable Livelihoods research group Dr Cooper Schouten; NSW DPI training coordinator honey bees Mark Page; NSW DPI education officer honey bees Kelly Lees; NSW DPI honey bee industry development officer Dr Madlen Kratz; NSW DPI bee biosecurity officer Rod Bourke; NSW DPI technical officer Plan Bee Emily Noordyke and NSW DPI technical specialist honey bees Elizabeth Frost.
- For more information on the field day or to register visit: tocal.nsw.edu.au/events/tocal-beekeepers-field-day
