2012 Annual Report
1a.Objectives (from AD-416):
The proposal addresses importation biological control of the soybean aphid. The soybean aphid recently invaded North America from Asia. First discovered infesting U.S. soybean fields in 2000 in 10 midwestern states, the soybean aphid has since spread to the eastern seaboard, west to Kansas, Nebraska and the Dakotas, and south to Mississippi and Georgia. In 2003, it infested 42 million acres of the 75 million acres of soybean grown in the U.S., causing $100 million of damage. Since then, insecticide treatment for the aphid has become widespread throughout the primary soybean producing states. The research in this proposal will be to continue importation and host range testing of natural enemies for biological control of the soybean aphid. The approach will be to import promising natural enemies, rear imported parasitoid species in quarantine, and expose them to a range of aphid species to determine which ones they are capable of attacking under laboratory conditions.
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.
Since soybean aphid was accidentally introduced into the United States 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 petitions to the North American Plant Protection Organization for introduction of two of these, APHELINUS GLYCINIS and APHELINUS RHAMNI, to control soybean aphid. On the basis of these petitions, we applied to APHIS-PPQ for permits for field release of these parasitoids species. We plan to release A. GLYCINIS and A. RHAMNI against soybean aphid in Minnesota in 2012-2013. Introduction of these parasitoids could greatly reduce damage by soybean aphid to United States soybean production.