August 21, 2013
Purple Loosestrife in the Little Fresh Pond Wetland
A large stand of the invasive wetland perennial, Purple Loosestrife (Lythrum salicaria) has dominated this wetland on the golf course north of Little Fresh Pond for many years, crowding out the cattails and other desirable native species that provide habitat and food for birds.
In 2006 the Friends of Fresh Pond Reservation and the Cambridge Water Department collaborated to carry out a control program that utilizes Galerucella beetles, native to Asia where L. salicaria evolved, which live and feed only on the loosestrife.
Beetles were purchased and released in 2006 and the following 6 years before any signs of reduction in size and numbers of the loosestrife were observed. In 2012 an improvement was noticeable but small. This year the difference is obvious. The loosestrife are no longer taller than a person - or the cattails - and many of the other native plants such as Blue Vervain (Verbena hastata) are as tall or taller.
In theory the beetles are now established and will continue to consume the Loosestrife. The plants will not disappear entirely, but they will be reduced in numbers and vigor so that biodiversity can be reestablished.