The use of an integrated model of pest spread and commodity markets to estimate the cost of a pest outbreak

There are significant benefits in integrating a biological spread model into economic assessment of the cost of pest incursions (such as varroa mite or Mexican feather grass) on agricultural industries. To illustrate the potential usefulness of an integrated approach, a generic bioeconomic model is developed by linking a simple stochastic pest spread module, built around a set of logistic spread equations, and a partial equilibrium module of the market for an affected agricultural industry. The pest spread module estimates the damage over time, while the partial equilibrium module estimates the resultant effect of a reduction in supply on the commodity market. The estimated effects on market variables are then used to estimate the cost of a pest outbreak. In this study, the cost of a hypothetical pest outbreak is estimated for three scenarios: (1) do nothing; (2) control actions to slow the spread; and (3) control actions aimed at eradication of the pest. The estimates are derived for a large number of random values of the spread rates specified in the logistic functions. The study also presents the frequency distribution of benefits of implementing the two control strategies.