Gardens may give flowers and plants life, but they can also be a death sentence for its most frequent visitors: bees.
Plants sold at major retail nurseries are often treated with pesticides harmful to bees, according to a report released Wednesday by the Pesticide Research Institute and Friends of the Earth, an international network of environmental organizations.
The groups purchased plants from retail nurseries, including Home Depot, Lowe's, Walmart and Orchard Supply Hardware in 18 cities across the U.S., as well as three provinces in Canada. They then sent the plants off to a laboratory to measure the presence and concentration of pesticides in the greenery. Testing showed that 51% of store-bought plants had levels of a group of harmful pesticides known as neonicotinoids that were high enough to kill honey bees, bumble bees and other pollinators "outright."
Neonicotinoids are commonly used pesticides in agriculture. More than 140 crops in the country, including corn, soy, wheat and canola seeds, are treated with neonicotinoids. They're also some of the most damaging pesticides to bees. Taken up through roots and leaves, the pesticides weave their way throughout an entire plant, eventually reaching the nectar on which bees feed. At high levels of exposure, neonicotinoids kill bees by attacking their nervous systems. Lower levels of the pesticide can impair bees' foraging and navigating abilities, disrupt their memory, and suppress their immune systems.
Neonicotinoids have previously been linked to the country's shrinking bee population. Last June, more than 50,000 bumble bees, or about 300 colonies, were found dead or dying in a Target parking lot in Oregon. The culprit was a neonicotinoid pesticide called dinotefuran, which had been sprayed on nearby trees to keep honeydew from dripping onto parked cars.