The Purple Loosestrife Biocontrol Beetle

Biocontrol is the use of a natural predator or pathogen to limit or eliminate a certain pest species.  The Galerucella beetle was approved by the USDA for use in 1992 as a biocontrol agent for purple loosestrife.  Since then, the beetles have been released in Massachusetts at both the Great Meadows National Wildlife Refuge and the Parker River National Wildlife Refuge.   Through the Office of Coastal Zone Management Massachusetts Wetlands Restoration Program Purple Loosestrife Biocontrol Project, beetles had been released at 10 different sites in Massachusetts, all of which are being monitored for purple loosestrife damage.  While the Cambridge Water Department and Friends of Fresh Pond Reservation will oversee the biocontrol project at Fresh Pond Reservation, the Office of Coastal Zone Management has extended their technical expertise as we have developed the project.       

The Galerucella beetle has been known to travel up to 10 miles to find new purple loosestrife on which to feed and lay eggs.  In fact, a small amount of beetle damage was observed on purple loosestrife at the Reservation during the summer of 2006.  These beetles could have traveled from project sites in Concord and Lincoln.  The Galerucella beetle goes great distances to find purple loosestrife because it will not mate or lay its eggs on any other species of plant.  The beetle will occasionally nibble on other vegetation once purple loosestrife has been depleted, but will ultimately move on, leaving the native vegetation intact. 

Galerucella beetles are native predators of purple loosestrife in Europe.  Of the 100 insects initially investigated for use as a biocontrol agent, Galerucella calmariensis and G. pusilla are two of the 4 insect species currently used in the US to control purple loosestrife.  The beetles live and breed exclusively on purple loosestrife, and during host specificity testing, starved rather than eat associated wetland vegetation.  This, along with its reproductive abilities makes this beetle an excellent biological control species.

Lifecycle of the Galerucella Beetle

 Taken from: Alyson Loos and David Ragsdale, “Biological Control of Purple Loosestrife: A Guide for Rearing Leaf-feeding Beetles”