Bees are vulnerable to acute pesticide poisonings from direct sprays, spray drift, contact with treated surfaces, and ingestion of contaminated pollen, nectar, or water. Insecticides are usually the cause.
Preventing pesticide-related bee kills
The best way for pesticide users to prevent bee kills and protect native pollinators is to avoid using pesticides toxic to bees on blooming crops or near hive locations. However, acute bee kills can be minimized even where pesticides are applied by using less-toxic products, accounting for bee habits and hive locations, and timing applications appropriately. In particular, applicators can reduce risks if they do the following:
- Avoid insecticide applications to blooming crops that are attractive to bees.
- Avoid all use of systemic insecticides that are toxic to bees. These pesticides persist in the plant for a long time after application (months to years), so avoiding application only during bloom will not protect bees.
- Select lower toxicity chemicals or chemicals having a short residual time.
- Know the locations of nearby hives and avoid applications during windy conditions or when winds are blowing from the treated area towards beehives
- For short residual time pesticides, time applications to occur in the evening or at night to avoid killing or contaminating foraging bees.
Oregon State University has an excellent publication entitled How to Reduce Bee Poisoning from Pesticides that PRI recommends for more information.
The Pesticide Environmental Stewardship Program as part of the Center for Integrated Pest Management has guidelines on Protecting Pollinators.
How to Report a Bee Kill
If you notice symptoms of pesticide poisoning, it is important that you collect as much information as possible about the kill. The Pollinator Stewardship Council (PSC, an organization of beekeepers) is helping beekeepers report poisoning incidents and can guide you through the process and help you get a report in to the EPA so the incident is tracked. For optimum regulatory response, it is important to do the following:
- Observation: Take photos or videos of your hives and any dead bees, and gather any notes you have made about the prior health and history of the affected hives. Determine the prevailing wind direction at the time of the kill and make a note of any pesticide applications you are aware of that may be related to the bee kill. Find out as you can about location, applicator, and pesticide(s) used. Remember that planting treated seeds can release dust that is highly toxic to bees.
- Investigation: Request a bee kill investigation from the State Lead Agency for pesticide enforcement in your state. In most states, this is usually the Department of Agriculture or Department of Environmental Protection. While US EPA does not investigate pesticide misuse incidents, you may contact the Regional US EPA office in your area to inform them of the incident, and that you have requested an investigation from your State Lead Agency. An investigation should include an inspection of the site and interviews with people familiar with the bees and the site, sampling of bees and/or potentially contaminated vegetation to test for pesticide residues, and inquiries into where the pesticide contamination may have originated. Some beekeeper organizations have regionally specific instructions for requesting an investigation and local knowledge about agency response. See our list of Beekeeping Organizations for those in your state.
- Documentation: PSC can help you with this, but if you choose to submit an incident report yourself, be sure to report the bee kill incident with the National Pesticide Information Center (NPIC) to ensure that there is accurate information on the number of bee kills nationwide. Commercial beekeepers should use the Ecological Pesticide Incident Portal available on the NPIC web site. For the general public, NPIC prefers calls to 1-800-858-7378. NPIC is open from 7:30am – 3:30pm PST. You should also send an email with a brief summary of the incident to US EPA Headquarters in Washington, DC.
- Notification: If you know the pesticide associated with your bee kill incident, report the incident to the pesticide manufacturer as well. Manufacturers are required by law to submit reports of adverse effects to the US EPA. If you know the pesticide that was applied, you can find contact information for the manufacturer by searching for the specific product at the Pesticide Action Network PesticideInfo web site.
The process of reporting a bee kill resulting from pesticide poisoning is not straightforward. PSC can help with the logistics of reporting. PRI is part of US EPA’s Pollinator Protection Workgroup that is providing advice to US EPA to improve the system. If you have comments or suggestions, let us know by putting a comment in the box below and we’ll make sure your concerns are highlighted in the discussions with US EPA. Unfortunately, EPA seems particularly unresponsive to feedback on this issue, but if they don’t hear anything from beekeepers when poisoning incidents occur, they think everything is fine, so it is important to report all pesticide-related bee kills.