Volunteers with the Nashua River Watershed Association purple loosestrife biocontrol project recently monitored 17 sites in Ashburnham, Ayer, Clinton Groton, Harvard, Leominster, Lunenburg, Pepperell and Shirley to record invasive loosestrife coverage and the presence or absence of Galerucella beetle populations at the sites.
This type of beetle, obtained from the New Jersey Department of Agriculture, eats only invasive purple loosestrife without harming native vegetation. Monitoring has shown that beetles released in previous years of the NRWA's project have overwintered and that they continue to damage loosestrife plants. It has also been found that the beetles move away from where they were released to new loosestrife infestations.
In 2008, the NRWA initiated a pilot biocontrol project to help eradicate invasive purple loosestrife in the Nashua River watershed and provide data to interested agencies on the success rate of this particular biocontrol method. In the first year, 25 individuals and families grew 150 pots of loosestrife as host plants for rearing beetles, and subsequently released 150,000 beetles that devoured loosestrife at seven infestation sites. By 2010, over 50 "citizen scientist" individuals and families were involved. They grew 272 pots of loosestrife and released 272,000 beetles at 16 sites in 10 towns. Loosestrife has declined by an average of 30 percent at those sites monitored by the project.
NRWA has continued the project this
NRWA project manager Kathryn Nelson is encouraged that the beetles have colonized and migrated into new areas. "We hope to be able to continue monitoring. Without the monitoring data, it will be difficult to understand what practices work to control loosestrife and stop its spread," observed Kath. "We have been so fortunate to have a great group of volunteers help with this project; they are so important to ongoing stewardship of healthy wetlands."
This year's project work has been made possible in part by a grant from the Community Foundation of North Central Massachusetts and a contribution from the Groton Garden Club. To learn about the project, or to volunteer to monitor a site, contact Kathryn Nelson at 978-448-0299, or email KathrynN@NashuaRiverWatershed.org. The NRWA is an environmental nonprofit organization that depends on memberships and donations for support.