Risk of introducing exotic fruit flies, Ceratitis capitata, Ceratitis cosyra, and Ceratitis rosa (Diptera: Tephritidae), into southern China.

Exotic fruit flies (Ceratitis spp.) are often serious agricultural pests. Here, we used, pathway analysis and Monte Carlo simulations to assess the risk of introduction of Ceratitis capitata (Wiedemann), Ceratitis cosyra (Walker), and Ceratitis rosa Karsch, into southern China with fruit consignments and incoming travelers. Historical data, expert opinions, relevant literature, and archives were used to set appropriate parameters in the pathway analysis. Based on the ongoing quarantine/ inspection strategies of China, as well as the interception records, we estimated the annual number of each fruit fly species entering Guangdong province undetected with commercially imported fruit, and the associated risk. We also estimated the gross number of pests arriving at Guangdong ports with incoming travelers and the associated risk. Sensitivity analysis also was performed to test the impact of parameter changes and to assess how the risk could be reduced. Results showed that the risk of introduction of the three fruit fly species into southern China with fruit consignments, which are mostly transported by ship, exists but is relatively low. In contrast, the risk of introduction with incoming travelers is high and hence deserves intensive attention. Sensitivity analysis indicated that either ensuring all shipments meet current phytosanitary requirements or increasing the proportion of fruit imports sampled for inspection could substantially reduce the risk associated with commercial imports. Sensitivity analysis also provided justification for banning importation of fresh fruit by international travelers. Thus, inspection and quarantine in conjunction with intensive detection were important mitigation measures to reduce the risk of Ceratitis spp. introduced into China.