Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
Rachel Carson National Wildlife Refuge Uses Galerucella Beetles to Control Purple Loosestrife in Maine
Northeast Region, August 29, 2008
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Since 1996, the Rachel Carson National Wildlife Refuge has been using Galerucella beetles for purple loosestrife control.  Purple loosestrife is an invasive plant from Europe with bright purple flowers that spreads aggressively through wetlands, outcompeting native flora.  The beetles are found in purple loosestrife's native range in Europe.  Galerucella are host specific to purple loosestrife, meaning that they only feed and lay their eggs on this species (Lythrum salicaria).  In years of testing and observations since their release, Galerucella beetles have been found to ignore even other plants of the same genus (some of which are native to Maine) and feed only on the invasive loosestrife.  Observations done by staff at the refuge have continued to support this conclusion.

            In early May, refuge workers dug up over 300 loosestrife plants and potted them.  A few weeks later, when the propagated plants were robust and the beetles on the refuge had emerged from their winter dormancy, refuge staff collected Galerucella from the wild.  Collection from sites on the refuge ensures that the beetles are acclimated to their environment, and spares the cost of buying the beetles elsewhere.  The beetles are transferred to the propagated plants, which have nets placed on them to contain and protect the beetles.  Rearing the beetles in a controlled environment allows us to maximize their productivity by protecting them from predators.  After completing a full life cycle, the beetle infected loosestrife pots are placed out in purple loosestrife infested areas.  Set loose from their pots, these beetles move to other loosestrife plants at the site, where they will hopefully breed and lay eggs the following spring.  Release sites are documented and monitored for the effectiveness of the beetles.  It usually takes three or more years of releases for a beetle population at a site to become self-sustaining.

            This year, 330 loosestrife plants were distributed for beetle release.  Working with fourteen different conservation partners, such as Land Trusts, Conservation Commissions, and Watershed Associations, beetles were released as far south as Kittery and as far north as Jefferson, Maine.  This is the largest release and widest distribution yet!  Thanks to all of our partners this year's release was a great success.

Contact Info: Karrie Schwaab, 207-646-9226 ext 23, Karrie_Schwaab@fws.gov
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