Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Pest suppression (control) and sustaining Tb freedom

New Zealand currently spends over $100 million each year on controlling possums, rats, and other small mammal pests to eradicate bovine Tb and to reduce the impacts of these species on our native plants and animals. In spite of this expenditure, Tb remains widespread and native species are still in decline.

We aim to help managers identify what combination of operational approaches is likely to be most efficient and cost-effective in providing long-term control of multiple pests. We will do this by using models that will enable managers to predict the relative cost-effectiveness of alternative operational approaches within each of three major pest suppression systems (Tb eradication, local elimination of pests, and combined on-going control of possums and rats). Thus far, we have focussed very largely on Tb eradication.

New Zealand has achieved ‘official Tb freedom’ in livestock, with <0.2% of herds now infected annually. However, Tb is still present in possums, and TB-possum management still costs farmers c. $54M p.a. That cost could be reduced by regional eradication of TB from wildlife, but that faces two impediments: high initial costs, and reliance on 1080 poisoning, use of which will be increasingly constrained.

We aim to overcome these constraints to Tb eradication by:

  • targeting Tb control expenditure and greatly shortening its duration
  • developing better multi-source surveillance systems to identify Tb-free areas sensitively and cheaply
  • reducing reliance on 1080, by using other tools, including (as a back-up) the development of aerially deliverable Tb vaccine for possums and using that in conjunction with lethal control.

Long-term, the resulting gains in efficiency and cost-effectiveness could potentially halve the currently predicted 50+yr timeframe and $1billion cost estimated for national eradication of Tb. Such gains in efficiency could also more than double the total area in which native species are adequately protected.


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