Internal EPA memos warn of insecticide impacts on honey bees

By Jon H. Harsch

© Copyright Agri-Pulse Communications, Inc.

WASHINGTON, Jan. 16 - EPA reports dating back to 2003 suggest EPA and USDA may have downplayed warnings from EPA scientists about the impact of certain pesticides on bee colonies. Current concerns focus on EPA's approval of neonicotinoids, including clothianidin and imidacloprid. The insecticides are used in seed treatments for corn, wheat, sugar beets, canola, soybeans, sunflowers, and other crops, but have undergone an uptick in media scrutiny as the result of internal EPA memos raising questions about the impact of clothianidin on honey bees.

As a result of the disclosure of an internal EPA memo linking health impacts on bees from the application of clothianidin and the widespread honeybee disappearance, the National Honey Bee Advisory Board and other organizations have requested the agency to remove clothianidin from the market. EPA officials have declined, contending that the organizations' complaint and the subsequent press coverage of the flap make erroneous assertions. However, the agency does call for more study.

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The 2010 EPA memorandum states that “clothianidin's major risk concern is to nontarget insects (that is, honey bees). Clothianidin is a neonicotinoid insecticide that is both persistent and systemic. Acute toxicity studies to honey bees show that clothianidin is highly toxic on both a contact and an oral basis.” The memo goes on to say that “information from standard tests and field studies, as well as incident reports involving other neonicotinoid insecticides (e.g., imidacloprid) suggest the potential for long term toxic risk to honey bees and other beneficial insects.”

France, Germany and Italy have banned neonicotinoids based on indications that the insecticides could be linked to honey bee Colony Collapse Disorder (CCD). The official EPA response is that EPA supports “research investigating pesticide effects on pollinators” and that “to date, we're aware of no data demonstrating that an EPA-registered pesticide used according to the label instructions has caused CCD.”

Meanwhile, in an annual report on CCD issued by USDA, Agriculture Department officials contend that “during the past 3 years, numerous causes for CCD have been proposed and investigated. Although the cause of CCD is still unknown, research has provided support to the hypothesis that CCD may be a syndrome caused by many different factors that work individually or in combination. Looking ahead, studies will focus increasingly on the interaction of multiple factors in causing CCD.”

Responding to current concerns about neonicotinoids and CCD, EPA officials tell Agri-Pulse that “the agency has accelerated a comprehensive reevaluation of these pesticides.” With both imidacloprid and nithiazine being reevaluated already, the agency says it will initiate the reevaluation of the remaining neonicotinoids - acetamiprid, clothianidin, dinotefuran, thiacloprid and thiamethoxam - beginning in 2012, moving those reviews up from original starting dates in 2013 through 2015. The officials say they are continuing to “work closely with USDA and other agencies to determine potential causes of CCD. If a link between pesticides and CCD is established, EPA stands ready to take the necessary regulatory action to ensure pollinators are protected.”

Internal EPA reports dating back to 2003, however, show that EPA scientists have raised serious concerns about clothianidin and imidacloprid. While these warnings are very specific in the EPA's internal documents, both USDA and EPA have avoided targeting neonicotinoids in their published documents, instead calling for “further study” rather than any restrictions on use.

Meanwhile, a December 2008 review of imidacloprid registration data says that the pesticide “is highly toxic to honeybees on an acute exposure basis; however, there is uncertainty regarding the potential chronic effects of imidacloprid on the honeybee colony.” As part of the registration review process, the agency said it is requiring field-based data on imidacloprid to better understand its potential impact on pollinators.

In addition, EPA says it will be working with federal and state officials, including representatives from USDA and the California Department of Pesticide Regulation, as well as the international community and other stake holders, to develop data and to better understand the potential impact of neonicotinoid insecticides such as imidacloprid on pollinators, using honeybees as a surrogate. “EPA is committed to a comprehensive review of the all available data and information and to proceeding in a deliberate manner so that actions to protect pollinators are based on sound science,” the agency says.

To read comments by CropLife America President Jay Vroom on the need for continued research on crop protection products, click HERE.

To read the full EPA memorandum from last November that prompted the National Honey Bee Advisory Board request, entitled “Clothianidin Registration of Prosper T400 Seed Treatment on Mustard Seed (Oilseed and Condiment) and Poncho/Votivo Seed Treatment on Cotton,” click HERE.

To read earlier EPA warnings in 2003, 2006 and 2007 about clothianidin's potential impacts on honey bees, click HERE.

To read a Dec. 2008 review of imidacloprid registration data, click HERE.

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