U.S. Fish and Wildlife Service Removes Controversial Chemicals from Mosquito Management Plan


May 5, 2014

Scott Hoffman Black, Executive Director; Xerces Society for Invertebrate Conservation, (503) 449-3793, [email protected]
George Kimbrell, Senior Attorney, Center for Food Safety; (971) 271-7372, [email protected]

U.S. Fish and Wildlife Service Removes Controversial Chemicals from Mosquito Management Plan

Mosquitoes to be treated with a least-toxic biological pesticide

PORTLAND, Ore.—The U.S. Fish and Wildlife Service (FWS) announced that it will manage mosquitoes on the approximately 300 acres of the Ni-les’tun Unit of the Bandon Marsh National Wildlife Refuge using only the biological pesticide Bacillus thuringiensis israelensis (Bti) to kill mosquito larvae, until the breeding habitat created inadvertently during a restoration project in 2011 has been remediated.

The Xerces Society for Invertebrate Conservation and Center for Food Safety (CFS) applaud FWS for the decision, which rescinds their earlier proposal to use two other insecticides, CocoBear (a petroleum oil) and methoprene (an insect growth regulator), which are more toxic to a range of invertebrates and other wildlife. Even more toxic pesticides sprayed to kill adult mosquitoes will not be used.

The Xerces Society’s Executive Director, Scott Hoffman Black, commented, “I am pleased that USFWS has chosen a mosquito management plan that will not cause undue harm to the Marsh’s unique habitat and wildlife.”

The biological insecticide Bti is the least toxic and most effective option to control the summer salt marsh mosquito Aedes dorsalis, a native species whose populations increased dramatically in the past year after a restoration project inadvertently created new breeding habitat. Aedes dorsalis is not an important vector of disease, but its aggressive daytime biting activity and unusual abundance prompted calls for control.

The Xerces Society, along with the majority of residents and farmers in Bandon, halted an initial proposal by the county and the FWS to spray toxic pesticides over 10,000 acres in the Bandon area in September 2013, with the result that only 300 acres in the marsh were treated with a less-toxic larvicide, but one that still posed substantial risks to nontarget organisms. Xerces and CFS are pleased that this outdated response has been replaced by a plan that uses monitoring to detect when larvae have risen above threshold abundances to trigger targeted treatment of breeding areas with a least-toxic larvicide.

“We are pleased that the Service has reversed course, after we explained to them that their actions violated U.S. environmental laws,” stated George Kimbrell, Senior Attorney for the Center for Food Safety. “We will remain vigilant in watchdogging the agency’s practices and protecting our nation’s wildlife refuges from unnecessary and harmful pesticides.”

The Bandon Marsh National Wildlife Refuge is the last substantial tract of salt marsh remaining on the southern Oregon coast and is home to diverse wildlife including clams, shrimp, salmon and bald eagles. It is used by thousands of migrating birds as well as by threatened species such as Coho salmon and snowy plover. These and other unique and threatened habitats should no longer be threatened by outdated methods of mosquito control.

Xerces’ Aquatic Program Director, Celeste Mazzacano, notes that this decision is only the first step. “There are still a lot of unanswered questions. We look forward to an open and collaborative process to ensure an effective and safe management plan.”

Monitoring populations of mosquito larvae and targeting specific problem sites for treatment with a least-toxic larvicide such as Bti effectively reduces the numbers of biting mosquitoes while protecting nontarget animals from the effects of toxic substances and sustaining the insects and crustaceans that lie at the heart of every food web.


For more information:

Fish and Wildlife Service Plan for Mosquito Control at Bandon Marsh: http://www.fws.gov/oregoncoast/PDF/FONSI_Bandon_Marsh_NWR_Mosquito_Control_PlanEA.pdf

Read Xerces Society and Center for Food Safety’s comments to U.S. Fish and Wildlife Service: https://xerces.org/wp-content/uploads/2014/05/CFS_XercesComments_BandonMarshEA_April14_Final.pdf

Fish and Wildlife Service’s Responses to Comments: http://www.fws.gov/oregoncoast/PDF/Bandon_Marsh_NWR_Mosquito_Control_PlanEA_comment_responses.pdf

Ecologically Sound Mosquito Management in Wetlands report, https://xerces.org/mosquito-management-wetlands/

Read previous media releases from the Xerces Society about Bandon Marsh NWR spraying proposals: https://xerces.org/2013/09/03/xerces-opposes-bandon-marsh-spraying/

Protecting the Life that Sustains Us

The Xerces Society is a nonprofit organization that protects wildlife through the conservation of invertebrates and their habitat. Since 1971, the Society has been at the forefront of invertebrate protection, harnessing the knowledge of scientists and the enthusiasm of citizens to implement conservation programs worldwide. To learn more about our work, please visit www.xerces.org.