Natural enemies wanted for poisonous vines

U.S. agriculture officials are joining Cornell University scientists to stop the spread of pale and black swallow-wort vines.

The twining vines -- members of the milkweed family recently classified as invasive species -- have spread rapidly since the mid-1990s. The plants are threatening the monarch butterfly, altering ground cover and affecting habitat for grassland birds. The plants also are growing with increasing vigor in some maize and soybean fields, and are altering forest regeneration patterns.

Cornell scientists are teaming with the U.S. Department of Agriculture's Agricultural Research Service, which operates a federal laboratory at Cornell, to find natural enemies to halt the plants' steady conquest of local ecosystems across the northern United States and Canada.

"The collaboration between Cornell and the USDA involves studies of the plants' biology to identify weak links in the life cycle that should be targeted, if possible, for biological control," said Lindsey Milbrath, a USDA-ARS research entomologist at Cornell.

As does the common milkweed, swallow-worts release lightweight seeds with featherlike tails that are dispersed by wind and passing deer. Between two to eight plants can germinate from each seed.

Copyright 2006 by United Press International