Scientists, with few exceptions, have agreed that pesticides can weaken bee populations.
And this time, the commercial sector seems to have joined the fold. According to a new report released Tuesday by the environmental activist group Friends of the Earth, retailers are phasing out certain bee-harming pesticides in their products – a rare case in which activists successfully used science to prompt changes in business practice.
"Our data indicates that compared to two years ago, fewer nurseries and garden stores are selling plants pre-treated with systemic neonicotinoid insecticides," Susan Kegley, a chemist at the Pesticide Research Institute and lead author of the report, told the Los Angeles Times.
Neonicotinoids are synthetic pesticides that are designed to imitate nicotine-based insecticides, which are found in leafy plants such as tobacco. In recent years, scientists have found correlations between neonicotinoid use and bee population decline. On Tuesday, conservation ecologists found that these chemicals may in fact cause a number of long-term issues for pollinators, The Christian Science Monitor reported.
"The evidence against neonicotinoids now exists in key bee brain cells involved in learning and memory, in whole bees, entire colonies and now at the level of whole populations of wild bees," Christopher Connolly, a neurobiologist and bee expert at the University of Dundee in Scotland, told Reuters.
But not everyone is on the same page about pesticides. Chris Harfield, a bee health specialist with the National Farmers Union, noted that while the new study was "another interesting piece to an unsolved puzzle," there was still no concrete proof of causation. Representatives from Bayer CropScience, the primary manufacturer of the neonicotinoid imidacloprid, have echoed that sentiment.
"Over its 20-year history, there has not been a single documented honey bee colony loss that can be attributed to a labeled use of imidacloprid," Bayer CropScience spokesman Jeff Donald told the L.A. Times.
But businesses are already swearing off the stuff, according to Friends of the Earth. More than 60 retailers – including The Home Depot, Whole Foods Market, BJ's Wholesale Club, and Lowe's – have promised to phase out nursery plants that have been treated with neonicotinoid.
"The market is shifting away from selling bee-killing pesticides, and retailers including Ace Hardware and True Value are lagging behind their competitors," Tiffany Finck-Haynes, a campaigner with Friends of the Earth, told the L.A. Times.
Other companies have approached the shift more tentatively. True Value will consider a three-year neonicotinoid phase out, but only when alternative pesticides become commercially available. Wal-Mart has stated that it will defer to future hazard assessments by the Environmental Protection Agency.
Nearly 144 tons of imidacloprid were used on California farms in 2013, predominantly by wine-grape growers, according to state Department of Pesticide Regulation, the L.A. Times reports. The chemical is also used frequently to control urban pests, such as termites.
Neonicotinoids have been linked to a number of bee health issues, including queen failure, decreased foraging, and communication breakdown in hives. Other factors, such as habitat loss and disease, may also factor into recent bee die-offs.