A honey bee collects pollen
A honey bee collects pollen | Emma Gallimore

Lower pesticide levels in plants still enough to harm bees, study finds

Plants marketed by major retailers as bee-friendly have been shown to contain fewer pesticides, but some still have high enough concentrations to hurt or kill bees, according to a report published on Tuesday.

Gardeners Beware 2016, published by Friends of the Earth and the Pesticide Research Institute, is a follow-up to testing for neonicotinoid pesticides conducted in 2013 and 2014.

“A neonictoinoid is an insecticide that has the same mechanism of action as nicotine,” said Susan Kegley, lead author on the study and CEO of the Pesticide Research Institute. “It’s very very toxic to bees and will kill them with very very small doses.”

The Gardeners Beware study found that 23 percent of flowers and trees tested contain neonicotinoid at levels that can harm or kill bees, down from 54 percent in 2013.

“For the average customer, the news is that it’s good news,” Kegley said. “Customers made their voices heard and said, 'we don’t want to be killing bees,' and Home Depot and Lowes responded with policies.”

Both Home Depot and Lowes have committed to reducing or eliminating neonicotinoid insecticides in the plants they sell. According to Gardeners Beware, more than 65 garden retailers, nurseries, and landscaping companies have done the same.

According to the Lowe’s 2015 Social Responsibility Report, the retail chain announced plans to phase out the sale of products that contain neonicotinoid pesticides within four years. The Healthy Gardening section of Home Depot’s website states that over 80 percent flowing plants sold by Home Depot are not treated with neonicotinoids and that they will completely phase out that insecticide on live plants by 2018. 

Other retailers have been less quick to respond. 

“Walmart recognizes the importance of pollinator health in the environment and wants to provide the best products for our customers’ needs,” said Ragan Dickens, director of sustainability communications at Walmart. “As we continue to rely upon the Environmental Protection Agency to review and authorize effective, safe chemistry, we also advocate for the continuous improvement of environmentally friendly products for our customers.”

The company is studying the issue, Dickens said, but Walmart does not yet have a plan in place to reduce neonicotinoids. A search of Walmart’s 2016 Global Responsibility Report showed no mention of neonicotinoids.

Ace Hardware and True Value did not respond to requests for comment.

According to a 2014 press release from the White House, pollinators contribute more than $24 billion to the U.S. economy, and honey bees alone contribute more than $15 billion.

Dr. Carol Armatis, who has been raising bees in  Maine for about 30 years, said she has seen firsthand  the effect pesticides can have on bees.

“I work in a greenhouse during the late winter and early spring. They use pesticides and fungicides and, unfortunately, I see a number of dead honeybees on the ground,” Armatis said. “They shouldn’t be dying in the spring.”

Not all bees exposed to neonicotinoids die. In small does, neonicotinoids impair the immune system and reproductive ability. They can also make it difficult for bees to navigate, which means bees who have flown out foraging can’t find their way back to the hive.

Neonicotinoids were introduced in the mid-nineties as a replacement for pesticides that were even more toxic to humans, Kegley said. Today, many pollinators are focusing on less toxic chemicals and alternative methods to control pest populations.

“They're using biological controls, so they use bugs that eat other bugs,” Dickens said. “Bugs build resistance to pesticides, but there's no resistance to being eaten.”