Status of an ongoing biological control program for the invasive vine, Persicaria perfoliata in eastern North America

Mile-a-minute weed, Persicaria perfoliata (L.) H. Gross (Polygonaceae), an aggressive annual vine native to Asia, has invaded forest edges, light gaps, open fields, and riparian borders in eastern North America. It was accidentally introduced into Pennsylvania in the 1930s and has since expanded its range north to Massachusetts, south to North Carolina, and west to Ohio. A biological control program was initiated in 1996, and in 2004, a permit was issued for release of Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae), a host-specific weevil initially collected in China. Since 2004, the biology of the weevil in its introduced range has been studied, along with its impact on P. perfoliata, which can be substantial. Weevils have been released in ten states through 2010, and populations have increased considerably at many sites. Although P. perfoliata continues to expand its North American range, natural and human-assisted dispersal of R. latipes is reducing its negative effects. Here we review and assess the current status of the biological control program.