As the US agriculture sector awaits a final opinion from the Environmental Protection Agency (EPA) on the threat to bee populations from neonicotinoid-based pesticides (neonics), at least two states – Minnesota and Maryland – are taking matters into their own hands.

Honeybee populations have been declining dramatically in the US for three decades, threatening billions of dollars in crops. A survey of more than 20,000 beekeepers conducted by the Department of Agriculture and released in May of this year showed that for beekeeping operations with five or more colonies there were 8 % fewer honeybee colonies on Jan. 1, 2016 than a year earlier.  According to one estimate, Maryland lost more than 60% of its hives last year, higher than the national average of 42.1%.

Per executive order from Governor Mark Dayton, Minnesota – the third-largest soybean producing state in the US – plans a strict ban on the use of neonics, unless farmers can verify that they face “an imminent threat of significant crop loss.” Where and on whom the burden of proof will lie has not yet been determined.

The proposed restrictions stemming from a special review of neonics carried out by the state government have won praise from environmental activists. "Minnesota just became the national leader in protecting pollinators," said Lex Horan, an organizer for Pesticide Action Network.

In Maryland, the new rules, which will take effect from 2018, have been sent to Governor Larry Hogan to be signed into law. They are less restrictive than Michigan’s, barring only consumers from using the products in their home gardens and placing no restrictions on professional gardeners and farmers.

As amateur gardeners in Maryland will still be able to buy the pesticides from other states or on the internet, making the ban difficult to enforce, the state government expects to have to spend some $1 billion to enforce the legislation. In recent years, however, major retailers including Lowe’s, Home Depot, and Whole Foods have made efforts to eliminate any bee-killing pesticides from their stores. In April, US garden care products manufacturer Ortho announced plans to phase out neonicotinoids in eight products used to control garden pests and diseases by 2021.

Since the EU’s 2013 moratorium on neonicotinoids, beekeepers and environmentalists across the US have been calling for nationwide restrictions. So far, Minnesota and Maryland have been the only states to act, although cities such as Portland and Eugene, Oregon, and Seattle and Spokane, Washington, have limited the use of the pesticides. State authorities in Minnesota said they want lawmakers to give them the authority to regulate the sale and use of treated seeds, a power now in the hands of the US Environmental Protection Agency (EPA).

After the Agriculture Department failed to establish a link between neonics and the bee deaths, the task has fallen to the EPA to examine the role the pesticides may play in bee colony deaths. In a report published early this year, the agency said preliminary studies had shown that neonics pose a “significant risk” to honeybees when used on cotton and citrus, but not when used on other big crops such as corn, berries and tobacco. At the same time it noted that the practice of treating seeds with the chemical “seemed not to harm bees.” The four-stage review of the hazards is due to be completed in 2018.

Worldwide, neonics are mostly sprayed on crops to fight insects, but the trend in the US is increasingly toward pre-treating the seeds. Monsanto is by far the largest player in this field – one reason why it is being hotly pursued by Germany’s Bayer, which has a much smaller position in this end of the market.

Along with farmers, who said they hoped other states would not follow Minnesota's lead, some agronomists said they were unhappy with the planned ban on neonics. Removing the widely used pesticides would leave farmers more dependent on a smaller number of chemicals to control bugs, said one, making it more likely that pests would develop resistance to those chemicals.