THE VARROA MITE CRISIS IN NEW SOUTH WALES
******** UPDATE ******** The National Management Group has decided that eradication of Varroa Mites from Australia is no longer technically feasible. So, on 19 September 2023, the NSW DPI Varroa Mite Eradication Program came to an end. The DPI baiting program, using the toxic pesticide, Fipronil, also ended on 19 September 2023. However, active pesticide residues from earlier baiting work, going back to late 2022, may still be in the environment in some areas. Aussie Bee is currently updating the information on this page in the light of these major developments. |
How it will affect native bees &
What you can do to help!
Aussie Bee > Native Bees and the Varroa Mite Crisis
by Dr Anne Dollin,
Australian Native Bee Research Centre
INTERIM UPDATE: Sunday 8 October 2023, 10.00am
Topics:
1. The situation so far.
2. How will Varroa Mites affect native bees?
3. How has the eradication effort affected native bees?
4. Do you have native bees in affected areas? HOW TO PROTECT THEM!
5. How native bees could help save Australian agriculture.
Above: a red-brown Varroa Mite parasite on a developing European honeybee. Image by Denis Anderson.
1. The situation so far
Varroa Mites, devastating parasite of European honeybees, were discovered in honeybee hives at Newcastle, NSW, on 22 June 2022. Sadly, by 15 September 2023, surveillance by the NSW Department of Primary Industries (DPI) revealed that Varroa Mites had spread to 277 locations in NSW (see Red Zones on map below).
Above: The DPI declared Red Zones around each site where Varroa Mites were detected. Until 19 September 2023, the DPI ran a Fipronil baiting program in these Red Zones, in an attempt to eradicate the Varroa Mites.
Drastic steps were taken by the DPI to try to eradicate this Varroa Mite incursion. About 30,000 managed European honeybee hives were euthanised in the Red Zones shown in the map above and a baiting program to destroy feral nests of European honeybees was progressively rolled out in these areas.
Finally, on 19 September 2023, the National Management Group controlling the response made the decision that it was no longer feasible to eradicate the Varroa Mites from Australia. The Varroa Mite eradication work, including the baiting program, ended, and apiarists began work to manage this pest in their European honeybee hives instead.
Varroa Mites still remain active within large areas of NSW, especially in the Newcastle, Central Coast and Kempsey areas. Varroa Mites do not directly affect native bees (see Section 2). However, the after-effects of the DPI baiting program may continue to impact native bees for some time (see Section 3).
2. How will the Varroa Mite affect native bees?
Fortunately, research has shown that Varroa Mites cannot attack Australian native bees directly, as native bees have a very different biology from European honeybees.
Other flow-on effects are still possible though. Mite-infested hives of European honeybees may carry high levels of bee viruses and some of these viruses may spill over to native bees. Read more.
Varroa Mites, as they spread, will drastically reduce the number of feral European honeybee nests in the bush. This will reduce competition for nectar and pollen resources in the bush, which should benefit some native bee populations.
On the other hand, from late 2022 until September 2023, the DPI attempted to destroy all feral European honeybees in the Red Zones, using sugary baits containing Fipronil, a highly toxic pesticide. This baiting work has now ended. Nevertheless, residual pesticide in the environment could still impact native insects in these areas.
3. How has the eradication effort affected native bees?
In an effort to rid Australia of this devastating European honeybee parasite, the DPI tried to destroy all feral European honeybee colonies that were nesting in tree cavities in the Red Zones. By September 2023, the combined Red Zone areas covered over 1.5 million hectares.
The DPI eradication effort in the Red Zones involved the use of baits laced with the highly toxic pesticide, Fipronil. Pesticide residues in the environment could still impact local native bees and other pollinators in these areas.
Above: The DPI declared Red Zones around each site where Varroa Mites were detected. Until 19 September 2023, the DPI ran a Fipronil baiting program in these Red Zones, in an attempt to eradicate the Varroa Mites.
During the baiting program, many feral European honeybee foragers visited the baiting stations and took Fipronil back to their nests, killing these colonies. Unfortunately, Fipronil can remain active in honey for over two years (see reference 1). So, the stored honey in these poisoned feral European honeybee nests could still endanger native bees that are in the Red Zones for a long time (see reference 2).
It is difficult to know how much Fipronil could still be in the environment in a particular Red Zone, as this depends on many factors. More Information on this to come.
If you have native stingless bees in a Red Zone, there are steps you can take to protect your bees (See Section 4, below).
4. Do you have native bees in affected areas? HOW TO PROTECT THEM!
Native bees in the Red Zones (see map above) could be exposed to Fipronil, a highly toxic pesticide. Until 19 September 2023, the DPI Varroa Mite eradication program used Fipronil to poison feral European honeybee nests in the Red Zones (see details in Section 3, above). Honey in these dead nests may be contaminated with Fipronil and this pesticide could remain active for about two more years.
Our previous advice to people who had native stingless bees within a Red Zone was to remove these hives from the Red Zones for up to three years.
As we gather further information on the current situation, this advice still stands. More Information on this to come.
5. How native bees could help save Australian agriculture.
This crisis highlights the vital importance of developing native bees as alternative pollinators for Australian agricultural crops. As Varroa Mites gradually spread across the country, massive losses of European honeybees will occur throughout Australia. The pollination services of native bees and other insects will become crucial to support Australian agriculture.
Recent research in Australia has demonstrated that native bees, including our stingless bees and blue banded bees, can be effective pollinators of many Australian agricultural crops. Other Australian native insects, including flies, beetles, butterflies and wasps, also contribute important pollination services to crops.
New crop management systems, which help Australian native bees and other insects to perform their vital pollination services for our Australian agriculture, must be developed as a matter of great urgency!
