The photo below was taken along Greenbelt trail 10 near Shirley’s Bay in 2004, just west of Ottawa, where the beetle had caused substantial damage to the plants. Plants at that site produced only a few stunted flowering shoots.
The best evidence for the impact of a biological control agent involves taking measurements of the target before and after the agent has been released. Unfortunately, funding for well designed before-and-after studies is often unavailable. An alternative approach involves comparing the target at sites with and without the agent, as long as those sites are matched for as many other factors as possible. To learn more about one such study, and to help track the distribution of the loosestrife beetle, visit