Assessment of risk of introduction of Cylas formicarius elegantulus (Coleoptera: Brentidae) into weevil-free areas in the southern United States.

We assessed the risk associated with introduction of sweet potato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae), from infested areas to noninfested areas via shipment of sweet potato, Ipomoea batatas (L.), roots within the southern United States. Our study quantifies the effectiveness of risk mitigation procedures of sweet potatoes before shipment in relation to introduction of the weevil. The risk assessment relied on literature and expert information to determine appropriate parameters. Using a computational model, Monte Carlo simulations were conducted to estimate the likelihood of introduction of sweet potato weevil. Risk management options were incorporated and the risk analyses were performed to assess how the risk could be reduced. The study found the risk of introduction of the weevil for both domestic shipment and imports of sweet potatoes into new areas within the southern United States to be low. Sensitivity analysis was performed to assess model stability and the impact of parameter changes. Based on the sensitivity analysis, the most critical input was the postharvest mitigation, followed by the number of weevils per ton of sweet potatoes. We concluded that maintaining mitigations with monitoring in conjunction with public education to stop illegal transport of sweet potatoes and alternate hosts would significantly reduce the risk of introduction.