Project details
Status: Completed
At a glance
- A study by TIA has highlighted the impact Varroa mite will have on crop pollination in Tasmania if the parasitic mite becomes established in the state.
- The study was prompted by the spread of Varroa on mainland Australia, which is wreaking havoc on European honey bee colonies.
- Many agricultural crops in Tasmania rely on feral honey bee colonies for pollination. A major decline in feral honey bees could reduce pollination services currently supporting Tasmanian crops, including fruit, berry and seed crops.
- The study was conducted between December 2025 and June 2026.
The need for research
The project examined the likely contribution of feral honey bees and other background pollination services to Tasmanian fruit, berry and vegetable seed production. It was prompted by the spread of Varroa on mainland Australia which is wreaking havoc on European honey bee colonies. Managed honey bee colonies can be monitored and treated for Varroa by beekeepers, but feral honey bee colonies are unmanaged and likely to be at greater risk if Varroa becomes prevalent in Tasmania.
Many agricultural crops in Tasmania rely on feral honey bee colonies for pollination. Varroa can reduce feral honey bee populations by more than 90 per cent within several years of establishment. A major decline in feral honey bees could reduce pollination services currently supporting Tasmania crops, including fruit, berry and seed crops.
Tasmania is currently Varroa-free but if it were to establish in the state the impacts to agricultural industries would be significant.
Collecting data
The project investigated how Tasmanian fruit, berry and vegetable seed crops are pollinated. The study used grower and industry surveys to collect information on the number of managed honey bee hives placed in different crops during flowering. Researchers then compared those stocking rates with published benchmark recommendations.
Growers provided valuable information about how many managed honey bee hives they place in crops during flowering. The data helped the research team identify crops and regions where background pollination, like feral honey bees, plays an important role.
It's hard to distinguish between feral and managed honey bees so directly measuring the contribution of feral bees is difficult. By comparing grower-reported hive use with published benchmark rates, researchers could identify crops where managed hive use appeared lower than expected. It indicated where background pollination services may be important.
The findings
The findings suggest that some fruit crops, particularly apples in the Huon Valley, may be relying strongly on background pollination services, including feral honey bees. If feral honey bee populations decline to due to Varroa, apple growers who currently use few or no managed hives may need to review their pollination plans.
By contrast, crops such as cherries, berries and vegetable seed crops appear to be more directly reliant on managed hives. This means that their main Varroa-related risk may be increased hive costs, reduced hive availability and hive quality issues.
The study found that vegetable seed production is highly dependent on managed hives. If Varroa increases the cost and complexity of maintaining strong hives that could have implications for seed growers as well as fruit and berry growers.
Message for growers
Researchers are urging Tasmania growers who rely on managed hives to talk to their beekeepers about Varroa preparedness, including hive monitoring, treatment plans, hive strength, future availability and potential changes in pollination costs.
The findings found that growers don't need to immediately change what they're doing. They're being encouraged to understand how much they currently rely on managed hives versus background pollination, and plan ahead for a future where honey bees may be less abundant and managed hives may become more expensive or harder to secure.
Practical advice for growers
- Consider how future changes in hive availability and cost could affect pollination planning.
- Review current pollination arrangements in case Varroa becomes established in Tasmania.
- Apple growers using few or no managed hives should consider whether additional hives could be sourced if background pollination declined.
- Talk to pollination providers about their capacity to maintain strong hives under Varroa conditions.
- Ask how hive strength and quality will be assessed before hives are placed in crops.
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Acknowledgements
The research team gratefeully acknowledges the growers and seed industry representatives who contributed their time and shared information about their crops and pollination practises. Their participation made this work possible and provided valuable insight into the current use of managed hives and background pollination services in Tasmanian crop production. The researchers also acknowledge the support of the Department of Natural Resources and Environment Tasmania, whose funding enabled this project.