Garden plants that homeowners buy to attract bees and butterflies may be poisoning them, according to reports from environmental groups.

“Gardeners Beware” by Friends of the Earth reports that bee-friendly plants sold at big-box stores often have been pre-treated with a neonicotinoid, a class of insecticide that kills or sickens bees.

According to the report released Wednesday, 51 percent of garden plant samples bought at top retailers in 18 cities — Walmart, Lowe’s and The Home Depot — contained neonicotinoids.

As of Thursday, The Home Depot and BJ’s Wholesale Club said they are taking steps to no longer sell plants with neonicotinoids or to label the plants that have been treated with them.

Locally, Gammon’s Garden Center in Auburn does not sell any plants with neonicotinoids, sales manager Tyler Gammon said Thursday. The company makes sure plants it buys from growers are neonicotinoid-free, he said.

The Friends of the Earth report is a follow-up to a similar study last year, which showed 40 percent of plants sampled contained a neonicotinoid, said Heather Spaulding of the Maine Organic Farmers and Growers Association, which worked with Friends of the Earth on the report.

“This year showed over half the samples studied had it. It’s very prevalent,” Spaulding said.

She said people have become more aware that bees are stressed and are trying to help by planting bee-friendly plants, “only to find out these plants are poisoning bees,” Spaulding said. “There’s no labeling,”

MOFGA did its own sampling on plants bought this spring at the Augusta Home Depot and Lowe’s. It sampled four bee-friendly plants: daisies, poppies, the pincushion flower and coreopsis. “All but the poppies tested positive for neonicotinoids,” Spaulding said.

She said neonicotinoids often are used in the soil in which plants are grown, and becomes “systemic” in the plant because it is taken in through the roots. “The chemical is in every part of the plant,” Spaulding said. “When the bees feed on the plant, it can kill them or make them sick.”

The report is not surprising, said Maine state apiarist Tony Jadczak, the bee expert with the Department of Agriculture, Conservation and Forestry.

“(Neonicotinoid) is an insecticide. Bees are insects,” Jadczak said. People forget that insecticides are meant to kill insects, including bees.

Sometimes neonicotinoids are injected into the trunks of trees and often is applied to soil. The chemical is considered less toxic than the old class of pest-fighting chemicals, such as DDT, Jadczak said. “We’re making progress at a snail’s pace.”

Neonic insecticides are absorbed by the plant and remain there for a long time, he said. How long depends on many factors, he said, such as the strength of the dose or whether it was mixed with a fungicide, which can make it more lethal.

“I have documented garden center plants shipped from the South where bumblebees visit and were dead on the concrete,” Jadczak said. He investigated and discovered a fungicide was mixed with neonicotinoid.

The outcome of this year’s “Gardeners Beware” report may lead to labeling, Jadczak said. “The study is pointing out that people don’t know what the plants are treated with.”

Consumers who don’t want plants treated with neonicotinoid should ask the salesperson whether the plant has neonicotinoid. If that person doesn’t know, he or she can check with a supervisor.

MOFGA’s Spaulding said use of the insecticide is unnecessary. “You don’t need to grow a plant with neonicotinoid. There are plenty of people in Maine growing certified organic plants.”

The U.S. Environmental Protection Agency is looking into plants pre-treated with neonicotinoids.

Multiple factors play a role in honeybee declines, including loss of habitat, parasites, disease, genetics, poor nutrition and pesticide exposure, said Linda Strauss, spokeswoman for EPA’s Office of Pesticide Programs.

“EPA is evaluating the neonicotinoid pesticides for home and garden plants, as well as other uses, as a high priority,” she said Thursday in a written statement.

bwashuk@sunjournal.com

Big-box stores making changes

Statement from The Home Depot’s manager of corporate communications, Catherine Woodling:

“The Home Depot is deeply engaged in understanding the relationship of the use of certain insecticides on our live goods and the decline in the honeybee population. We’ve been in communication with the EPA, insecticide industry and our suppliers for many months to understand the science and monitor the research. We are encouraged and support the White House’s Pollinator Health Task Force.

“We’re glad to provide customers with alternative products for their insecticide needs and are actively working with our live goods suppliers to find alternative insecticides for protecting live goods and bees. We will also require all of our live goods suppliers to label plants that they have treated with neonicotinoids by fourth quarter 2014.”

Statement from BJ’s Wholesale Club’s Scott Williams, assistant vice president for quality assurance and environmental stewardship:

“BJ’s Wholesale Club is proud to partner with Friends of the Earth in this important initiative to keep bees safe in the environment. Bees are an essential part of a healthy ecosystem and healthy world, which is why BJ’s has worked closely with our vendor partners to provide lawn care, dispensable pesticide, pet care and fresh-cut floral products that are neonicotinoid-free.

“We require all vendors to disclose the use of any neonicotinoids in nursery or plant-able products (blueberry bushes, tulip bulbs). We also require any vendors using neonicotinoids in nursery or bedding plants to submit their plan and/or process used to protect bees when using neonicotinoid (timing segregation, etc.). We are asking all vendors to be out of neonicotinoid plants by the end of 2014, and/or we will include a label that states ‘treated with neonicotinoid, use caution around pollinators.'”

Statement from Walmart Communications’ Susan Saronitman:

“Wal-Mart shares the concerns of others regarding pollinator health, including the health of bees. Like many other environmental and social issues in agriculture, the neonicotinoid issue is very complex. We are monitoring the science on this closely, and we look forward to the findings from the White House’s National Pollinator Health Task Force, announced in the last week.

“We are actively engaging with many stakeholders, including scientists, suppliers, farmers and customers, to explore additional steps we can take to enhance the health of bees and other pollinators in the food and garden supply chains.”