Minnesota’s new law that allows beekeepers to file for compensation when bees are killed by pesticides has prompted 10 investigations since its enactment in 2014 by the Minnesota Department of Agriculture’s Pesticide and Fertilizer Management Division.

Out of those 10, two investigations conducted in 2015 found clothianidin residue on dandelion flowers and live and dead bees on a hobby bee farm near Scandia in Washington County.

Clothianidin is an insecticide--a neonicotinoid-- which reacts on the central nervous system of insects. It is approved for use as a seed coating treatment to protect the seed from various pests and diseases. Depending on the manufacturer and formulation, clothianidin is available for use on corn (seed, sweet and popcorn), soybeans, sorghum, sugar beets, canola and rapeseed.

Two beekeepers had separate apiaries, consisting of overwintered or new colonies, on one farm. They reported to MDA that a neighbor had been planting a day prior to their bees’ deaths. MDA’s investigation confirmed that a nearby field had been planted with treated corn seed prior to the beekeepers’ reporting bee losses.

MDA investigators follow a detailed protocol after receiving a bee kill complaint. They open and examine bee colonies, take hive samples, evaluate the queen bee, count live and dead bees. All samples, including samples taken of nearby vegetation, head to MDA and USDA labs for pesticide residue analysis.

For a beekeeper to receive compensation under the law, MDA needed to define “acute pesticide poisoning.” A panel of MDA scientists agreed to base acute poisoning on a dead-to-live bee ratio depending on the time of year, colony size and if a pesticide is found.

In these two cases, MDA investigators found the number of bee deaths to meet the threshold for acute pesticide poisoning. However, clothianidin residues were found at relatively low levels on dead bees while residue levels were high on dandelions. Investigators hypothesize that considerable degradation took place due to rain and light exposure before samples could be collected. Compensation for the beekeepers was a minimum of $230 per hive. The law caps compensation at $20,000.

Research ongoing

Bayer, a global manufacturer of neonicotinoid pesticides, continues to research and evaluate the bee issue and maintains that there is no scientific evidence linking neonicotinoids to a decline in honey bees or other insect pollinators.

Jeffery Donald, Bayer spokesman, noted that honey bee colony numbers in North America has increased since neonicotinoids were introduced.

“In [the Minnesota investigations], the forensic evidence does not confirm clothianidin exposure was the cause of bee death,” Donald said. “The MDA analytical lab found residues below the acute level of concern, and the USDA analytical lab found no detectable residues.”

Reported incidents involving honey bees associated with corn planting are rare, especially considering the many millions of acres of treated seeds planted each year, he added.

Still, Bayer developed and introduced a seed lubricant in 2014 that is calls Fluency Agent. The lubricant replaces talc and graphite in seed coatings to reduce potential dust exposure during planting.

Safe handling always important

So how does this law affect you? If you were responsible for applying the seed treatment in the course of a bee kill investigation, MDA could issue an enforcement action against you that would include a financial penalty payable to the affected beekeeper.

Keep in mind your overall stewardship practices. As suggested by the American Seed Trade Association:

-Keep your planter in optimal working condition. Calibrate and clean it. Seed at recommended rates. When planting, direct planter exhaust downward to the soil surface where possible.

- Reduce dust. Follow planter manufacturer recommendations for use of seed flow lubricants. Avoid shaking the bottom of the treated seed bag when filling the planter. Dust could have settled during transport. Be mindful of wind speed and direction when opening seed containers and during filling or emptying the planter.