ARS | Publication request: Vegetative expansion and seed output of swallow-worts (Vincetoxicum spp.)

Submitted to: International Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: April 27, 2007
Publication Date: October 1, 2008
Citation: Milbrath, L.R., Averill, K.M., Ditommaso, A. 2008. Vegetative expansion and seed output of swallow-worts (Vincetoxicum spp.). In: Julien, M.H., Sforza, R., Bon, M.C., Evans, H.C., Hatcher, P.E., Hinz, H.L., Rector, B.G. (Editors). International Symposium on Biological Control of Weeds, April 23-27, 2007, La Grande Motte, France. CAB International Wallingford, UK. p. 251.

Technical Abstract: Swallow-worts (Vincetoxicum rossicum, pale swallow-wort, and V. nigrum, black swallow-wort) are herbaceous, perennial, twining vines related to milkweeds (Apocynaceae). Pale swallow-wort is native to Ukraine and southeastern European Russia; black swallow-wort is native to southwestern Europe. Both species are becoming increasingly invasive in the northeastern United States and southeastern Canada. They grow in both high and low light environments in a variety of disturbed and undisturbed habitats. The success of a classical biological control program for swallow-worts will be dependent on the availability of critical biological and ecological data about the target species, such as which life stage(s) are important for population growth and most sensitive to control efforts, which in turn will affect the selection of candidate biological control agents. Assessments of the rate of vegetative expansion and reproductive output of isolated swallow-wort plants have begun at several sites in New York State, including old field and forest understory habitats within sites. In one year, the number of tillers per pale swallow-wort plant increased by 45% in old fields and 19% in the forest understory. Follicle (seed pod) production was generally lower in the forest understory than old-field habitats. Monitoring will continue for at least the next two years.