2011 Annual Report 1a.Objectives (from AD-416) Rear and test host specificity of Asian parasitoids that are candidates for biological control of the soybean aphid. 1b.Approach (from AD-416) Rear imported parasitoid species in quarantine. Expose them to a range of aphid species to determine which ones they are capable of attacking under laboratory conditions. Draw inferences about potential host range after introduction against soybean aphid. 3.Progress Report Since soybean aphid was accidentally introduced into the US around 2001, it has become the major pest of soybean. To find biological control agents to introduce against soybean aphid, we have imported and reared in quarantine 45 populations of soybean aphid parasitoids in at least 16 species from China, Japan, and Korea during the last 10 years. We have evaluated host specificity of 24 populations of APHELINUS; 21 had broad host ranges and have been eliminated from consideration. Three species of APHELINUS were found to have narrow host ranges. We submitted and received approval for a petition to the North American Plant Protection Organization for introduction of one of these, APHELINUS near ENGAEUS, to control soybean aphid. We plan to release APHELINUS near ENGAEUS in Minnesota in 2012. Introduction of these parasitoids could greatly reduce damage by soybean aphid to US soybean production. Monitoring was achieved through telephone calls, emails, and meetings.