New risk-based approach to Varroa mite zones

The NSW Department of Primary Industries (DPI) biosecurity leader Dr John Tracey said it would mean zoning distances would be different based on the individual risk each infestation posed.

He said the National Management Group for the Varroa mite had endorsed the proposal.

It's hoped the new plan will limit the impact on the bee industry, though the standard zoning strategy remains "essential" for the larger eradication "red zones".

"Using this risk-based approach will reduce the impact of the response on industry and applies a scientific approach to decision making," Dr Tracey said.

He said it will also be cost-effective and manage the resources being utilised in the battle against Australia's "biggest ever pest emergency".

The new risk-based approach will see new regional "outlier" infestations be assessed based on factors like how many mites, the length of time hives have been present, and tracing linkages.

A "risk profile" of a zone would be established and determine the right zone size.

Where zones meet a good level of protection, a reduction in size could be on the table, but where the level is not met, the standard 10-kilometre or 25-kilometre zones should remain.

Dr Tracey said the Varroa mite response had 14 months of experience behind it since the pest was first detected during routine surveillance by bee biosecurity officers at the Port of Newcastle in June last year.

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The outbreak was initially traced further from the port within the Newcastle area.

Dr Tracey said it was now clear that a different approach could still be effective, as had been shown in almond pollination sites in the southern part of the state.

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"Where infested hives have been recently moved, have low mite levels and a clear link to an older eradication zone, the risk profile is actually very low," he said.

"Whereas in situations where infested hives have been present for a long time, have high mite loads or unclear tracing links, the risk is high."

Despite the changes, other "red zones" will keep the standard zoning strategy for now.

"It has also been important during the delimitation of the Newcastle and Central Coast outbreaks due to the high number of infested premises, risk of natural spread of mites and length of time the infestation has been present," Dr Tracey said.

The NSW DPI is the lead agency in Australia's Varroa mite response, which involves the Consultative Committee on Emergency Plant Pests (CCEPP) and is governed by the National Management Group (NMG).

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