Treated plants put bees at risk, study says
But neonicotinoids were not detected in retail plant samples taken in Eugene
By Saul Hubbard, The Register-Guard – June 26, 2014
Home gardeners unwittingly may be exposing bees and other pollinators to a class of insecticides that has been increasingly linked to their deaths, according to a new study by environmental groups.
The study, released on Wednesday, tested 71 samples from plants purchased in the nurseries of large retailers — including Home Depot, Lowe’s and Wal-Mart — for neonicotinoid insecticides, or neonics. Thirty-six samples, just more than half, were found to contain varying amounts of neonics.
Of those, 40 percent contained two or more different types of neonicotinoids.
The study, titled “Gardeners Beware 2014,” was conducted by Friends of the Earth, a coalition of grass-roots environmental groups. Samples were taken from 18 cities in different regions of the United States and Canada, including in Eugene. The four samples from Eugene didn’t contain any neonics.
The study selected plants that are known to be particularly attractive to bees and, in some cases, are advertised as such. These included daisies, marigolds, lavender, yarrow, poppies and primroses.
The findings come as neonicotinoids — the most widely used insecticides in the world — are coming under increasing scrutiny in Oregon and worldwide for their impacts on bees.
After four large bee die-offs in Oregon last summer, the state banned the use of two types of neonicotinoids, dinotefuran and imidacloprid, on linden trees and others in the Tilia family.
A Eugene commercial pesticide operator had its applicator license suspended by the state last week after it was found to have broken the new rule. An estimated 1,000 bees died after the company sprayed 17 linden trees with a pesticide containing neonicotinoids. The company also could face a fine once an investigation by the state is completed.
Earlier this year, the Eugene City Council voted to ban the use of neonicotinoids on city property.
Bee die-offs are of concern to governments because of a well-documented decline in honeybee colonies. Such pollinators are crucial to the food chain, responsible for 1 out of every 3 bites of food that Americans eat, according to the U.S. Department of Agriculture.
In the new study of retailers’ nursery plants, the plants’ flowers and their leaves and stems were tested, and varying degrees of neonicotinoid concentration were found in different samples.
Eight of the samples contained concentrations deemed to be at “lethal” levels for bees, meaning that 50 percent of bees exposed to it would die within a 48-hour period, according to Susan Kegley, a study co-author.
The other positive samples contained concentrations that could impair bees’ sense of direction or immune system and potentially kill them if they were exposed to it over a prolonged period of time, the study’s authors said.
Once a plant absorbs a neonicotinoid, it cannot be extracted or washed off. Neonics can remain present in plants or soil for months or years.
Although there is scientific debate about long-term harm to bees from exposure to lower concentrations of neonics, scientists generally agree that neonics can be very harmful to pollinators at higher concentrations.
The study’s conclusions assume that concentrations found in different parts of the plant would be the same in its nectar, which bees consume. That’s the primary way bees are exposed to neonics directly.
Kegley, the CEO of Pesticide Research Institute, a Berkeley, Calif.-based environmental consulting firm, said the study didn’t key in on nectar testing because “it’s a much harder concentration to determine.” However, neonic concentration levels in different parts of a plant can vary wildly and tend to be lower in the nectar itself.
The study is a follow-up to a smaller study done last summer that yielded similar results. In that study, seven of 13 plant samples purchased from garden stores in the San Francisco Bay Area, the Washington, D.C., area, and Minnesota’s Twin Cities were found to contain neonics. In that small test, the entire plant was ground up and tested.
Kegley said the latest study “provides a pretty good picture” that the use of neonicotinoids to treat home gardening plants sold at big retailers “is common practice throughout the country,” although she acknowledged “that there’s still more (research) work to be done.”
In response to the findings, Lisa Archer of Friends of the Earth said in a prepared statement that “most gardeners have no idea that their gardens may be a source of harm to bees.”
“We’re calling on retailers to get neonicotinoid pesticides out of their plants and off their shelves as soon as possible,” she added. “Until then, gardeners should buy organic plants to ensure the safety of bees.”
Ron Jarvis, Home Depot’s vice president of merchandise and sustainability, said Wednesday that the company understands that bee numbers are falling and that “some information points to neonics at different (concentration) levels contributing to that.”
Last year, Atlanta-based Home Depot started seriously looking into the possibility of requiring its plant suppliers to phase out their use of neonics, Jarvis said. But doing so involves successful testing of alternatives first, he added.
“We can’t have a policy in place without truly understanding all the consequences of using alternatives,” he said.
In October, the company will begin labeling all the plants it sells that have been treated with neonics, Jarvis said.
Lowe’s issued a prepared statement Wednesday in response to questions about the study.
“Lowe’s is concerned about bee health, and for many months we have been closely monitoring the latest science from organizations, including the U.S. Environmental Protection Agency, the U.S. Department of Agriculture, environmental groups and respected universities,” the statement said. “All studies agree that the influences impacting the health of bees and other pollinators are very complex.
“Lowe’s supports ongoing efforts by the EPA and USDA to promote pollinator health, including the recently established (federal) Pollinator Health Task Force, which will work to foster a better understanding of pollinator losses, develop an education plan, and seek ways to increase and improve pollinator habitats.”
Another large retailer, BJ’s Wholesale Clubs, an East Coast company with 200 locations, has committed to require its plant suppliers to phase out or label any neonic-treated plants by the end of the year.
Lisa Arkin, executive director of Beyond Toxics in Eugene, said she believes that viable alternatives to neonics exist and are being used by organic farmers.
Retailers selling neonic-treated plants “is a restriction of people’s right to have a healthy garden,” she said. “That’s unconscionable on the part of the suppliers.”
Arkin said she’s pleased that the public is paying more attention to the potential harm caused by neonicotinoids.
“I think that folks really understand this issue, more than other environmental issues, because it’s connected to their food,” she said.