Risk assessment for the New Zealand National Pest Plant Accord: which species should be banned from sale?

M.J. NewfieldA and P.D. ChampionB

A Biosecurity New Zealand, Ministry of Agriculture and Forestry, PO Box 2526, Wellington, New Zealand.

B National Institute of Water and Atmospheric Research (NIWA), PO Box 11-115, Hamilton, New Zealand.


The National Pest Plant Accord (NPPA) is an approach used in New Zealand to manage the problem of invasive plants that are in the horticultural trade. It is a cooperative agreement between central government agencies, local government agencies and the Nursery and Garden Industry Association. Species included in the Accord list are legally prohibited from sale, propagation and distribution under provision of the Biosecurity Act 1993. There are hundreds of invasive or potentially invasive plants in New Zealand, but it is neither desirable nor feasible to include every invasive plant on the Accord list.

A robust and transparent weed risk assessment process is required to support decision-making and prioritization for which taxa to include on the Accord list. Criteria for inclusion in the Accord list were developed and assessments were conducted by members of a Technical Advisory Group (TAG). Approximately 200 taxa were assessed and prioritized by the TAG in 2005. No current weed risk assessment tool was available to determine taxa for the NPPA list, although some existing systems were used to provide additional information. The criteria and process used are described, and future directions and improvements are discussed.

Keywords: Invasive plants, horticulture, weed risk assessment.


Plant Protection Quarterly (2010) 25 (2) 75-78.