Canadian efforts to slow the spread of Emerald Ash Borer (Agrilus planipennis Fairmaire) are economically efficient

Abstract

Abstract The Emerald Ash Borer (EAB), Agrilus plaipennis (Coleoptera: Buprestidae) was introduced to North America more than two decades ago and has spread despite management efforts in both the United States and Canada. The insect kills most species of ash tree (Fraxinus sp.) and its management imposes costs to plant health protection agencies, forest industry, private landowners and municipalities. The United States Department of Agriculture – Animal and Plant Health Inspection Service (USDA-APHIS) has deemed existing regulation efforts in the United States to be ineffective and has removed federal regulations designed to limit the spread of EAB. The Canadian Food Inspection Agency (CFIA) is also trying to determine if continued regulation of EAB in Canada is worthwhile. Here we show that the benefits of slowing the spread of EAB via regulation are likely greater than the costs of implementing regulation if it is minimally effective (i.e. more than 25% effective at preventing anthropogenic spread). To evaluate the economic efficiency of existing Canadian EAB regulations, we examined trade-offs between the monetary benefits of regulation and the costs of regulation. Specifically, we simulated the spread of EAB under various levels of regulation effectiveness and estimated the timing of EAB arrival and associated ash mortality in urban and rural settings. Delaying ash mortality via regulation also delays management costs, a benefit to ash tree owners/users. Our findings suggest that an economic justification to continue regulating the insect exists based on monetary costs alone. The net present value of regulation (benefits less costs) is estimated to range between $23 million to $240 million, depending on the level of regulation effectiveness. Additional environmental and social benefits not addressed here would likely increase the value of EAB regulation but appear unneeded to justify such efforts on allocative efficiency grounds.