Biosecurity Buzz
by Mike Allerton ABA Biosecurity Officer
Are You Ready for Winter?
As the foraging season winds down and floral resources diminish, members of ABA affiliated clubs must prepare their colonies for the cooler, leaner months ahead. Preparing hives for winter is one of the most important practices of the beekeeping calendar - whether you’re on the South Coast of New South Wales, the highlands of Canberra, or the subtropical north of Queensland. The fundamentals are the same: ensure colonies are healthy, well-provisioned, and protected from the dual threats of cold and pests. With the presence of Varroa destructor now established across much of NSW, and the ever-present risk of small hive beetle (Aethina tumida), winter success depends on timely, regionally appropriate management. The good news? With a little planning, losses can be minimised and colonies can emerge strong and ready for spring.
WINTER PREPARATION BASICS FOR ALL REGIONS
Regardless of where you keep bees, the following core actions apply:
- Monitor and manage Varroa well before winter bees are produced (usually by late summer).
- Check colony strength—weak hives should be combined.
- Reduce hive volume if necessary to match cluster size.
- Ensure sufficient stores—typically 15–20 kg of honey, depending on local conditions.
- Prevent moisture buildup—ventilate/insulate hives and tilt forward slightly.
- Defend against SHB by removing debris, using traps, and avoiding excess space.
Winter isn’t always cold in Australia—but it is often a time of scarcity. Bees may need help staying healthy, dry, and fed.
Regional Considerations
South Coast (NSW)
Cool and damp with coastal influence. Varroa is present.
- Monitor mites from February onwards and treat by March.
- SHB is active through mild winters—use traps and reduce unused hive space.
- Insulation above brood helps with moisture control.
Sydney Basin
Urban microclimates can be warmer, but mite pressure is high.
- Urban reinfestation risk is elevated—monitor every 4–6 weeks.
- Robbing can occur—reduce entrances in weaker hives.
- Some forage may persist in sheltered areas—watch for continued brood rearing.
Central Coast and Hunter
Mild winters, SHB and Varroa both present.
- Expect SHB to remain semi-active through winter.
- Treat for Varroa after major flows end.
- Monitor food stores monthly and top up if needed.
Southern Highlands (NSW)
Cold winters with frost and occasional snow.
- Brood pauses are more common—consider oxalic acid dribble or vapour in winter.
- SHB is less active, but still monitor.
- Top insulation or quilts may help reduce condensation.
Canberra Region (ACT)
Cold continental winters.
- Long brood breaks ideal for oxalic acid mid-winter.
- Strong colonies with deep stores are essential.
- Provide insulation and moisture boards if needed.
Albury and Southern Slopes
Cold and dry inland conditions.
- Similar to Canberra: monitor for mite drop during brood breaks.
- Sugar bricks or fondant may be useful mid-winter.
- Combine weak hives early—rescue is unlikely after May.
Mid North Coast (NSW)
Subtropical climate with persistent SHB risk.
- Varroa requires aggressive control in late summer.
- Small colonies should be reduced to nuc boxes or single brood chambers.
- Beetle traps should be used regularly.
QLD: Gold Coast and Northern Queensland
Varroa recently detected in QLD vigilance is critical.
- Keep monitoring/detecting —soapy water or alcohol wash monthly.
- SHB is a major year-round threat—use traps and hygienic queens.
- Little or no brood break, so SHB and mites (when introduced) will thrive.
Conclusion
From the misty highlands to the subtropical coast, preparing hives for winter in Australia requires attention to both biology and climate. While Varroa destructor has changed the game in NSW, Queensland beekeepers must remain vigilant and ready to act. With consistent monitoring, proactive pest control, and sensible seasonal management, you can guide your bees safely through winter—and set them up for a productive spring ahead.
Varroa Response Winding Down
The last of Varroa Management Training Workshops for NSW are done. I had the privilege to help deliver nine workshops with some of the sector’s brightest beekeepers including Bruce White, Doug Purdie, Garth Miller and Torsten Englehardt. Attendees at every workshop expressed their appreciation for the information and the opportunity to ask questions.
Occasionally, the feedback was not so positive. Some hold strong opinions about letting varroa take its course and to then breed from the survivor bees. Yes, there are examples of countries that took that approach and they’ve made it through the other side. I’ve heard that Cuba is one such country.
I find it difficult to imagine how that would work in Australia. Do we just stand by and watch our colonies succumb to the cruel destruction left by varroa and their partners in crime, small hive beetle? Do we watch our crops fail due to no or inadequate pollination? Do we allow our commercial beekeeping brothers and sisters lose their businesses, their homes? What about those crop farmers? And then, after Australian agriculture collapses, are we prepared for the inevitable food shortages and high prices.
For the rest of us, who want to take the best care of our bees we can, there are still some resources available from the National Varroa Response:
- Varroa Development Officers (VDO) has dropped to three: Slavi Nenov, Simon Phillips and Dave Fairhall. They’re here for the rest of the year and ready to help you in dealing with varroa. Invite them to your club meeting or out to your apiary for expert knowledge.
- To arrange a VDO or BBO to speak at your club or help at your apiary go to Contact NSW — National Varroa Mite Management Program
Oxalic Acid in Cellulose Strips
Researcher, Dr. Belen Branchiccela in Uruguay led a team to study the effectiveness of oxalic acid in cellulose strips as an acaricide. The recently published study1 used the commercial product Varroxsan which is similar to Aluen CAP and with similar results2,3, currently undergoing registration with the APVMA.
The results found treatment to be 96.5% effective in winter and 92.6% effective in autumn. Treatment in spring prevented growth of the mite population but did not reduce it.
After 58 days of nectar flow with the strips in the hives, there was no detectable residue in the honey, nor was the moisture or acidity different between the treated and control hives. There was no impact on queens, bee population or brood survival, though the control hives had more brood.
It is noted in one cited study 4, that homemade attempts to replicate these slow-release products by impregnating oxalic acid and glycerine into shop towels was ineffective in the Southwest US climate.
Cited another study that found on an individual bee level exposure to oxalic acid dribble can cause “higher necrotic cell death in the midguts, degeneration of the rectal epithelium, and irreversible lesions in different bee organs.”
In short, Aluen CAP has high efficacy in autumn and winter, but in spring only prevents mite growth. Home made strips are not as good as commercial and that dribble delivery is more harmful to bees than strips.
Dribble is one of the approved delivery methods of ApiBioxal, the only permitted oxalic acid acaricide available in Australia. Aluen CAP will hopefully be permitted by this spring.
- Branchiccela, B., et al. (2025) “Oxalic acid in cellulose strips: towards an efficient and sustainable approach for the control of Varroa destructor.” Apidologie 56, 21. https://doi.org/10.1007/s13592-025-01149-0
- Maggi, M., et al. (2016) “A new formulation of oxalic acid for Varroa destructor control applied in Apis mellifera colonies in the presence of brood.” Apidologie 47, 596-605. https://doi.org/10.1007/s13592-015-0405-7
- Rodriguez, R., et al. (2020) “Control of Varroa destructor development in Africanized Apis mellifera honeybees using Aluen CAP (oxalic acid formulation).” https://doi.org/10.1080/01647954.2020.1806923
- Bartlett L., et al. (2023) “No evidene to support the use of glucerol-oxalic acid mixtures via paper towel for controlling Varroa destructor (Mesostigmata: Varroidae) mites in the South-east United States.” J Insect Sci 23(6), 18. https://doi.org/10.1093/jisesa/iead097
- Bacandritsos N/. et al (2007) “Efficacy of repeated trickle applications of oxalic acid in syrup for varroosis control in Apis mellifera: influence of meteorological conditions and presence of brood. Vet Parasitol 148, 174-178. https://doi.org/10.1016/j.vetpar.2007.06.001
Varroa Resistance Starting to Show?
Hastings Valley Beekeepers Biosecurity Officer, Leon Carle recently told me that several members have noticed what appears to be hygienic behaviour within their hives. The observed behaviour is uncapping which is one of the traits attributed to bees controlling varroa development.
Uncapping is the partial or complete removal of the cell cap in which a pupa is developing. It disrupts the environment within the cell and appears to disrupt the development of the immature varroa.
It’s worth noting that uncapping isn’t varroa specific. Bees uncap brood cells to help control diseases such as chalkbrood and foulbrood.
Maybe this observation in Hastings Valley hives could lead to embracing these bees into a varroa resistance breeding program.
Have you noticed uncapping in your hives?
AFB Minimisation Program
Let me know if your club has honey to submit for free AFB testing. There are AFB outbreaks across the state. Your samples can help map its presence.
Until next time.
Mike Allerton biosecurity@beekeepers.asn.au
“Always bee yourself and do your own sting”
