A garden plant labeled "pollinator friendly" would no longer need to be free of insecticides, under a change in state law moving through the Legislature.

Last year, after pressure from gardeners and environmentalists, lawmakers passed a rule that nurseries could not market plants as bee- and butterfly-friendly if they were grown with the controversial class of pesticides called neonicotinoids, which have been implicated in the global decline of honeybees and other insects.

This year, the nursery industry has successfully pushed back. New language approved by the House Monday and before the Senate as early as today, says nurseries can advertise a flower as good for bees and butterflies as long as it's not toxic enough to kill them after one sip of nectar or single load of pollen.

"There is a level of pesticide that is safe for pollinators," said Tim Power, head of government affairs for the Minnesota Nursery and Landscape Association. "Last year's law was passed based on an emotional response rather than scientific facts."

Advocates who supported last year's rules change say the new language is misleading to gardeners, who assume that a label with a bee or butterfly on it means that it's safe for insects.

"It's not friendly," said Kristy Allen, a Minneapolis beekeeper who testified in favor of the original law last year. "It's like saying, well, it's OK to eat this food that has a little bit of poison because it won't affect you right away."

Moreover, it makes the law unwieldy, said Vera Krischik, an associate professor at the University of Minnesota who studies insecticides and insects. The new language says that a plant labeled pollinator friendly can be treated with a neonicotinoid as long as it doesn't contain enough to kill an adult honeybee outright — a ceiling determined by the EPA when it approved the insecticide in the first place. But Krischik said nurseries use more than a dozen different insecticides, creating many ways an insect can be exposed.

"I'm afraid the change makes the law unenforceable," she said.

The national debate over insecticides is building even as bees continue their precipitous decline. An annual survey of 5,000 beekeepers nationally, released Wednesday, found that they lost 42 percent of their hives in the past year — the second worst decline since the survey began in 2010. Scientists blame many factors, including a flowerless landscape increasingly devoted to row crops, pests and diseases that spread from hive to hive, and pesticides.

Neonicotinoids have become the public focus of the debate because they have rapidly become the most widely used pesticide in the world. The chemical can be used as a spray, but is usually coated on seeds or doused on soil so plants take it up as they grow. That makes them much safer for people and mammals, but it makes the entire plant a neurotoxin for insects that feed on it.

In recent years, a growing body of research has found that, even at sublethal doses, the chemicals can interfere with an insect's ability to navigate and reproduce, and may make them more susceptible to disease and parasites.

The U.S. Environmental Protection Agency recently announced it would restrict new approvals of neonicotinoid insecticides until it completes a long-awaited scientific review of their effect on bees. The White House is soon expected to release a new national pollinator protection plan.

Minnesota is the only state to pass a labeling law designed to help consumers avoid insecticide treated plants that are also attractive to pollinators.

Now, the tug-of-war is just as much about what "pollinator friendly" means as it is about the use of insecticides.

Power said that the nursery industry has long used the term to describe a flower's characteristics.

"It's … talking about a plant that's attractive to pollinators in the first place," he said. "It has nothing to do with pesticides."

But gardeners, beekeepers and environmental groups say that was false advertising, and consumers had a right to know whether they were buying a plant that is attractive — but potentially toxic — to insects.

"Yes, you can attract them — and kill them or make them sick," said Rep. Rick Hansen, DFL South St. Paul, who sponsored the original law last year.

But nursery owners did not like the choices they were forced into, Power said. They had to make sure every plant was free of insecticide, or they had to remove any reference to pollinators on the tags and labeling.

They were also forced to use spray insecticides that killed many bees and butterflies when applied, and were much riskier for people.

"There's been a trade-off," said Marla Spivak, a professor and bee expert at the University of Minnesota. "They want to do the right thing."

It would help the nursery owners if their plants could contain a low level of insecticide, Spivak added.

"But I don't know that it would help bees," she said.

Josephine Marcotty • 612-673-7394