Varroa mites
Varroa mites (Varroa jacobsoni and V. destructor) are the most serious pest affecting honey bees worldwide.
The mites are tiny reddish brown external parasites of European honey bees. Varroa mites are a notifiable pest, which means if you suspect you have found signs of varroa mite in your hives, you must report it immediately by calling the Exotic Plant Pest Hotline 1800 084 881.
Hive surveillance reporting form
Please use hive surveillance reporting form to report any checks you have made on your hives, even if you do not find any suspect mites.
Reporting that you've checked and haven't found varroa mite will help provide further reassurance the mite hasn't entered Tasmania.
A new online form will need to be completed for each hive location, however for beekeepers with numerous hives, across multiple sites, a spreadsheet is also available for ease of reporting. To request a copy, please contact us on 6165 3777
or email: biosecurity.tasmania@nre.tas.gov.au
If you would like to report inspection results of other hive locations or inspection dates, please press “Submit” and complete a new form.
What can beekeepers do?
Beekeepers are encouraged to inspect and sample their hives regularly for signs of varroa mites.
Detection methods
The
mites are tiny reddish-brown parasites and individual mites are easily
identifiable to the naked eye. Varroa is similar in size to Braula fly
(Braula coeca) and can be detected in the hive using three main methods:
an alcohol wash, a sugar shake test, or through uncapping drones.
For more information about each of these detection methods follow the links below:
Important steps if varroa mite is suspected
It
is important when varroa is suspected in an apiary that the following
steps are taken by the beekeeper to reduce the risk of spread:
- Collect
a specimen of the suspect varroa mite and place it in a small jar of
methylated spirits. Keep the jar in a cool, safe place away from
sunlight. Don't mail or forward any samples until advised to do so by a
department apiary officer. Never take live specimens away from the
apiary as this may help to spread varroa.
- Reassemble the opened hive to its normal position.
- Mark
the hive with a waterproof felt pen (or similar) so it can be easily
identified later. Mark the lid and all boxes of the hive with the same
identification number.
- Thoroughly wash hands, gloves (and
gauntlets), hive tool, smoker and any other equipment to ensure varroa
is not carried from the apiary.
- Place protective clothes,
gloves, veil, bee brush and hat in plastic bag and leave them at the
apiary site until advised by a Biosecurity Tasmania Officer.
- Don't
remove bees or any hive components from this apiary as this could help
spread varroa. Before leaving the apiary, inspect your vehicle to make
sure there are no bees trapped inside or on the radiator. Check the tray
of the truck, ute or trailer as well. Boxes of combs and other hive
material on your vehicle which bees might enter must be left at the
apiary.
Above: European honey bee with a varroa mite on its back (image: Scott Bauer, USDA Agricultural Research Service)
Current status of varroa mite in Australia
Varroa destructor mites were detected (June 2022) in biosecurity surveillance hives in Newcastle, New South Wales (NSW).
The National Management Group (NMG) confirmed on 19 September 2023 that eradication of Varroa destructor (varroa mite) in NSW is no longer feasible based on technical grounds. As a result, NSW and has now entered a transition to management phase for varroa mite.
What the transition to management means for Tasmania
Tasmania remains free of varroa mite, all Tasmanian beekeepers are advised to remain vigilant in closely monitoring their colonies for any signs of the varroa mite.
Biosecurity Tasmania has put in place increased surveillance and inspection measures at Tasmania’s points of entry.
Restrictions on the import of bees, apiary products and used apiary equipment into Tasmania are already in place, but have been and continue to be reviewed in light of the varroa mite detection in NSW. See more information on the General Biosecurity Direction.
Description
- Adult female varroa are reddish-brown, shaped like a scallop shell, about 1.1 mm long and 1.7 mm wide and visible to the naked eye.
- Adult males are smaller and are yellowish-white. Both sexes have eight legs.
- The eggs are 0.5 mm long, milky-coloured and at first rounded.
- Females of Varroa jacobsoni, another exotic species, are smaller than females of V. destructor, being about 1.0 mm long and 1.5 mm wide.
Life cycle
Varroa only produce offspring when honey bee brood is present in hives.
Mated female varroa enter drone and worker brood cells containing mature larvae just before hive bees cap the cells. The female varroa move to the base of the cell and submerge themselves in the larval food. When the cell is capped, the submerged mites move to the larva and begin feeding.
Above: Varroa destructor mite on a bee pupa. Image: Gilles San Martin - Wikimedia Commons
Individual females lay up to six (6) eggs, beginning about 60 to 70 hours after the cell was capped and thereafter at intervals of about 30 hours. The first egg laid is male and all the others are female. Eggs are laid on the base and walls of the cell, and sometimes on the developing bee.
Development of female varroa from egg to adult takes about 8 to 10 days. The long interval between the laying of individual eggs means that mites of different stages of development may be seen in the one cell. Protonymphs hatch from eggs about 12 hours after laying. A larger duetonymph stage occurs before the final adult stage.
The single male varroa mates with its sisters while they are in the brood cell.
When the new adult bee emerges from its cell, the young varroa females and mother mite also leave the cell, often on the emerging bee.
How varroa spreads
The mites are very mobile and readily transfer between adult bees.
Varroa spread between colonies and apiaries when hive components, infested brood and adult bees are interchanged during normal apiary management practices.
The transport of hives, used beekeeping equipment and queen bees by beekeepers is also a very effective means of spread.
Foraging and drifting bees and swarms can also spread varroa. In the case of foragers, mites can move from the bee to a flower and then hitch a ride with another bee or insect visiting the same flower.
Varroa is not spread in honey.
Likely impacts of the varroa mite establishing in Australia
If varroa mite were to establish in Australia, European honey bees and the pollination services provided could be reduced by 90-100 per cent. This would result in:
- introduction of restrictions on the movement of hives to limit spread, which could reduce the availability of hives in some regions
- a significant impact for apiarists, who would face higher costs to manage their hives
- impact on producers of crops such as almonds, apples and cherries that rely on pollination from European honey bees.
Changes to the Tasmanian import status for bees, related products and equipment
Following recent detections of Varroa mite (Varroa destructor) in NSW, the Tasmanian Chief Plant Protection Officer has put in place a General Biosecurity Direction (Emergency) to further prevent the introduction of this honeybee parasite into Tasmania.
This Direction will come into effect as of 5pm on Wednesday 6 July 2023 and remains in effect for 6 months, unless it is revoked earlier. The Direction prohibits the import into Tasmania of any:
European honey bee (Apis mellifera); or
any animal product produced by, or from, a European honey bee other than commercially produced bee products such as honey filtered to a maximum 2 mm pore size and melted refined beeswax, or another process approved by the Chief Plant Protection Officer; or
and used beekeeping equipment; or
any other thing that may reasonably be suspected of being a carrier of bees, or any pest or disease that may affect bees.
Biosecurity Tasmania understands that a potential longer-term restriction on queen importation will impact Tasmanian businesses for the upcoming season, and will work closely with the Tasmanian industry to ensure we communicate alternative options. Realistically, producers should consider local alternatives in sourcing queens for the coming season.
General Biosecurity Direction (Emergency) bees, bee products and equipment (PDF 89Kb)
Visit the Bees, Apiary Products and Used Apiary Equipment webpage for more information.
Report anything suspicious
If you see anything suspicious, immediately call
Exotic Plant Pest Hotline 1800 084 881