Nelson emphasis shifts to slowing spread
Marco Gonzalez, Apiary Adviser, AgriQuality
Ltd, inspecting a destroyed feral hive (found
in a letter box) for varroa mite.
Photo: AgriQuality Ltd.
On 24 January, the Minister for Biosecurity announced the decision to cease the attempt to eliminate varroa bee mite (Varroa destructor) in the Nelson region.
Senior Policy Analyst with Biosecurity New Zealand (BNZ) Paul Bolger says the programme is now focusing on slowing the spread of the mite outside the known infested areas around Nelson, Tapawera and Pelorus.
Varroa, an invasive mite which kills bees, was first detected in apiaries in Nelson in June 2006, with further surveillance revealing infestations at Tapawera and Pelorus.
The decision to attempt elimination was made in August 2006 after the beekeeping industry asked the Government to reconsider the original decision made by BNZ to use control measures and education to manage the mite. The elimination attempt involved moving all managed hives out of the known infested areas to enable poisoning of the wild bee population.
"Theoretically, making the area 'bee free' would reduce the chance of varroa spreading from the wild to the managed bee population," says Paul. "An established varroa population hasn't been eliminated anywhere else in the world before, so there was never any guarantee our attempt would be successful."
The decision to cease the elimination attempt was made after low levels of varroa were found outside the known infested areas in December 2006, probably linked to the movement of pollination hives. "These finds increased the area needing to be poisoned by four times and would have also meant moving thousands of managed hives out of the area. The expanded poisoning area also included some rugged terrain that would have been difficult to lay bait stations in. These factors, along with the ever-present risk of human-assisted spread, made the eradication attempt unfeasible," says Paul.
A planned poisoning attempt last spring was delayed because the manufacturer of the preferred chemical, fipronil, wouldn't allow BNZ to use it for poisoning bees. Paul believes the spread is likely to have happened, even if poisoning had taken place in spring.
"Spread appears to be linked to the horticultural region at the western end of the infested area. Even if a poison had been available, it was never intended that the horticultural area would be poisoned in the spring, due to the need to retain bees for crop pollination.
"Humans are the biggest factor risk when it comes to spreading varroa – usually through inadvertent spread by beekeepers moving hives and equipment. We have movement controls in place but these can't provide a 100 percent guarantee varroa won't spread."
BNZ has been working closely with the beekeeping industry on the response, and consulted with them before the decision to cease the elimination attempt was made.
Since then, BNZ staff have met with Nelson and Marlborough beekeepers to discuss management and control options.
One of the keys to effective management of varroa is education. Paul says North Island beekeepers faced similar issues when varroa was found there in 2000.
"We ran practical, hands-on workshops for North Island beekeepers to help them manage varroa in their hives.
"Beekeepers were on a very steep learning curve, but most of them have adapted well to managing varroa. For many beekeepers, this has required a fundamental re-think of how they manage their businesses, rather than us tacking varroa treatment onto their existing management system."
The upper South Island has been declared a Controlled Area under the Biosecurity Act 1993, and restrictions are in place on moving bees, beekeeping equipment and other risk goods out of this area to the rest of the South Island. This will slow the southward spread of varroa, although BNZ believes it is inevitable the rest of the South Island will become infested.
However, to slow the spread eastwards from Nelson to Marlborough, additional measures have been put in place. Beekeepers moving risk goods past Wash Bridge and Pelorus Bridge are required to contact the permitting office on 0800 80 99 66. This decision was made after consultation with Nelson and Marlborough beekeepers.
"Additional surveillance in the Marlborough area will be carried out in autumn 2007 to determine whether varroa has spread to Marlborough. Surveillance will enable BNZ to review the location and need for control points within the Controlled Area," says Paul.
Bees 'hitch-hiking' on vehicles moving out of the Controlled Area is another way varroa can spread.
"Feral bees are known to establish hives in old logs and empty buildings which are often transported around the country," Paul says. "They are also attracted to goods such as sugar and fruit juice. The Varroa Agency Incorporated, an organisation comprising regional councils and the two national beekeepers' groups, ran an extensive information campaign for the transport industry moving goods from the North to South Islands earlier this year. BNZ will be supplementing this with a campaign targeting movers of these goods through the Controlled Area.
"BNZ is also continuing the feral bee destruction campaign, which has been running throughout the response. So far, we have destroyed 550 feral bee hives and swarms and encourage people in the Controlled Area to report sightings of feral bee hives and swarms to MAF's freephone number 0800 80 99 66."
Paul says the decision to discontinue the elimination programme was disappointing after the hard work put in by industry and BNZ staff. "However, we remain committed to working closely with industry to help slow the spread of varroa to the rest of the South Island and to give beekeepers information to manage varroa when they need it."
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Page last updated: 2 July 2010