My wife is a former employee of the Illinois Natural History Survey (DNR)
and is currently an employee of the Illinois EPA. Under the Illinois and
Indiana Seagrant she conducted local outreach programs on Purple Loosestrife
and its biological control. She informed me of the following URL. It is a
good resource on the origins of this exotic species and various biological
control methods.

http://www.inhs.uiuc.edu/cbd/loosestrife/bcpl.html

Ken Haller
Arlington Heights, IL