The optimal amount and allocation of sampling effort for plant health inspection

Plant import inspection can prevent the introduction of exotic pests and diseases, thereby averting economic losses. We explore the optimal allocation of a fixed budget, taking into account risk differentials, and the optimal-sized budget to minimise total pest costs. A partial-equilibrium market model is used to compute the economic consequences of pest invasion. An application to Dutch imports of chrysanthemum cuttings shows that the optimal allocation of a fixed inspection budget halves the cost of pest invasion compared to allocating the same budget equally over all imports. A budget increase that enables 42 per cent more inspection can reduce total societal costs by 81 per cent compared to smaller, constrained budget that ignores risk differentials.