Some 23 per cent of plants (14 out of 60 tested) from stores and nurseries tested by environmental activists contained pesticides at levels that could be harmful to bees. Two previous reports, in 2013 and 2014, revealed that more than half of the samples contained neonicotinoid traces.
"Our data indicates that compared to two years ago, fewer nurseries and garden stores are selling plants pre-treated with systemic neonicotinoid insecticides," said Susan Kegley, a chemist at the Pesticide Research Institute and lead author of the report by the institute and Friends of the Earth.
The study was of plants bought at Home Depot, Lowe’s, Ace Hardware, True Value and Walmart.
The Gardeners Beware 2016 report suggest grower production methods have resulted in reduced use of neonicotinoids in common garden plants overall.
Large retailers, including Home Depot and Lowe's, have made commitments to phase out use of these pesticides. Ace Hardware, True Value and Walmart have not yet made similar commitments to eliminate neonics in their stores.