Valuing the impact of plant pest and biological controls on New Zealand agriculture

The agricutural industry plays a key part of the New Zealand economy. However the incidence of plant pests in New Zealand threaten the viability of the sector. There are various options for controlling and mitigating the impact of these pests, and biological controls offer one potentially valuable solution. Economic analysis of these pests are vital to forming an appropriate policy response at the government level. Much of the literature on bio-security and biological controls focusses on a biological perspective rather than an economic one. This dissertation presents a more comprehensive framework for economic valuations of plant pests, with the use of a modified cost-benefit analysis (incorporating inputs from partial equilibirum trade modelling) to test the economic impact of plant pests and controls responses in New Zealand. Specifically, two case studies are examined: clover root weevil (Sitona lepidus), and its biological control Microctonus aethiopoides; and glassy-winged sharpshooter (Homalodisca vitripennis), and its biological control Gonatocerus ashmeadi. The analysis shows the impacts of clover root weevil, and glassy-winged sharpshooter, if left unchecked, are –NZ$604 million, and –NZ$5 million per year respectively. The biological control options for each pest would mitigate between NZ$338-431 million per year in the case of clover root weevil, and NZ$4 million in the case of glassy-winged sharpshooter