Volunteers with the Nashua River Watershed Association (NRWA) purple loosestrife bio-control 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 NJ 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 bio-control 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 bio-control 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 ten towns. Loosestrife has declined by an average of 30% at those sites monitored by the project.
NRWA has continued the project this year, training 10 new volunteers to identify loosestrife and to recognize Galerucella beetles at different life stages. Newly trained volunteers joined experienced team members and NRWA summer college interns to conduct the first monitoring of the season. Volunteers and NRWA staff are also rearing a new batch of beetles at the NRWA River Resource Center for release later this summer.
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 more about the project, or to volunteer to monitor a site, please contact Kathryn Nelson at (978) 448-0299, or email [email protected]. The NRWA is an environmental non-profit organization that depends on memberships and donations for support.