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Image of apiary training sponsored by DPR, Parlier, CA. June 2014

 Apiary training sponsored by DPR,
Parlier, CA June 2014

Neonicotinoid Reevaluation Progress and Protecting Bee Health

The California Department of Pesticide Regulation (DPR) is at the national forefront of the effort to protect bee health, taking proactive steps and a scientific approach to address concerns about the impact of pesticides on bees and pollinators health.


On February 27, 2009, DPR placed certain pesticide products containing neonicotinoids with the active ingredient: imidacloprid, thiamethoxam, clothianidin, and dinotefuran into reevaluation. The purpose of the reevaluation process is to provide DPR with a better understanding of the effects of neonicotinoids use on pollinators and provide a credible scientific basis for potential regulatory action to eliminate any significant impact resulting from their use on bee health.

DPR partnered with scientists at the U.S. EPA's Office of Pesticide Programs and Health Canada Pest Management Regulatory Agency (PMRA) to ensure that the required studies, and methods and procedures used to conduct studies on the effects of neonicotinoids provide useful and reliable information across the board to all three agencies for use in guiding their regulatory actions. A unified approach across jurisdictions is critical as bees and beekeepers are not limited by state borders, nor are their importance to agriculture and society. To protect bees and other pollinators DPR collaborated on making product labels (instructions) much easier to understand. The labels clearly explain that the uses of some neonicotinoids pesticide products are prohibited where bees are present. The updated labels have a bee advisory box and icon with information on routes of exposure and spray drift precautions. DPR made it a priority to review the amended labels in order to get them out into the California marketplace. All affected California products contain the pollinator protection label language.

Each of the four neonicotinoid pesticides have different application rates for specific crops, requiring a substantial number of studies to understand the impact of the different pesticides using the application methods used for each crop group. Studies are required for each of the four neonicotinoids as used in the most relevant representative situations to determine the level of residue that remains in the pollen, nectar, and leaves of plants after multiple applications – residue if found in high enough levels, could result in lethal exposure to adult pollinators. Tests were then required to determine what levels of neonicotinoid pesticide would have lethal effects on pollinator larvae. Finally, U.S. EPA required higher tiered honey bees studies with input from both DPR and PMRA Health Canada. Tier II studies (i.e. honey bee feeding studies) examine the effects on colonies following exposures to known concentrations of a pesticide in a food source fed to a bee colony. Tier III studies (i.e. full field studies) is a field-level test that looks at long-term effects under environmentally realistic exposure conditions. Each set of requirements has pushed the research one step further after inconclusive or preliminary results and analysis showed no likely significant hazards from neonicotinoid use under existing labels.

Other Information and Proactive Actions to Protect Bee Health

For content questions, contact:
Denise Alder
1001 I Street, P. O. Box 4015
Sacramento, CA 95812-4015
Phone: (916) 324-3522