(Beyond Pesticides, June 24, 2013) Just as Pollinator Week began last week, an estimated 50,000 bumblebees, likely representing over 300 colonies, were found dead or dying in a shopping mall parking lot in Wilsonville, Oregon. Authorities confirmed
 Friday that the massive bee die-off was caused by the use of a neonicotinoid pesticide, dinotefuran, on nearby trees. Then on Saturday, it was reported by The Oregonian that what could be hundreds of bees were found dead after a similar pesticide use in the neighboring town of Hillsboro.
According to the Xerces Society, this is the largest known incident of bumblebee deaths ever recorded in the country. Bumblebees, which are crucial to pollination of multiple berry and seed crops grown in the Willamette valley, have recently experienced dramatic population declines, a fate that is similar to other pollinators. Dan Hilburn, Director of plant programs at the Oregon Department of Agriculture (ODA), told Oregon Live that he's "never encountered anything quite like it in 30 years in the business." The incident highlights the difficulty of permitting in commerce such a highly toxic material that indiscriminately kills beneficial insects.
A recent study, An overview of the environmental risks posed by neonicotinoid insecticides, published in the Journal of Applied Ecology, documents that neonicotinoid persistence in soil and water can cause broad and far-reaching impacts on ecosystem health, much of which have undergone little scientific scrutiny. The author asserts that world leaders have failed to meet their commitment made at the 2002 Convention on Biological Diversity – to achieve a significant reduction in the rate biodiversity loss. He points to neonicotinoids as a potential cause of this failure, due to their long-term persistence in soil and water. He specifically points to soil dwelling insects, benthic aquatic insects, grain-eating vertebrates, and pollinators as being in particular danger from the use of these chemicals.
The ODA and Xerces Society had been working together to investigate the pesticide poisoning. After interviewing the landscaping company that maintains dozens of ornamental trees around the parking lot, ODA investigators learned that Safari, a pesticide product with the active ingredient dinotefuran, had recently been applied on Saturday, June 15 to control aphids. Dinotefuran is a neonicotinoid pesticide that is highly toxic to bees; the product's label strictly forbids its use if bees are in the area.
Scott Black, executive director of the Xerces Society, noted that the pesticide was applied to the tree while it was flowering, an action that violates the product's instructions. "Beyond the fact that a pesticide was applied to plants while they were attracting large numbers of bees, in this case the pesticide was applied for purely cosmetic reasons. There was no threat to human health or the protection of farm crops that even factored into this decision."
Neonicotinoids, including dinotefuran, can be broadly applied as a spray, soil drench, or seed treatment, however, the ability of these chemicals to translocate through a plant as it grows has led to the creation of a large market within chemical-intensive landscaping and agriculture. Once these systemic pesticides are taken up by a plant's vascular system, they are expressed through pollen, nectar and guttation droplets from which pollinators such as bees then forage and drink. Neonicotinoids kill sucking and chewing insects by disrupting their nervous systems. Beginning in the late 1990s, these systemic insecticides also began to take over the seed treatment market. Clothianidin and imidacloprid are two of the most commonly used neonicotinoid pesticides. Both are known to be toxic to insect pollinators, and are lead suspects as causal factors in honey bee colony collapse disorder. An extensive overview of the major studies showing the effects of neonicotiniods on pollinator health can be found on Beyond Pesticides' What the Science Shows webpage.
Several different crops in the Willamette valley of Oregon rely heavily on the pollination services provided by bumblebees. Blueberries, raspberries, blackberries and crop seed production, which are grown in Oregon, all rely on bumblebees for pollination. Mace Vaughn, pollinator conservation program director with the Xerces Society, told Oregon Live, "Bumblebees are the single most important natural pollinator in Oregon."
source: via email
Insecticide temporarily banned by Oregon Department of Agriculture after 50,000 bumblebees die in Wilsonville
WILSONVILLE, OREGON -- June 18, 2013 -- A bumblebee dies after falling off a Landen tree at Town Loop Shopping Center parking lot. An estimated 25,000 bumblebees were found dead beginning Saturday, the largest known incident in the United States. (Motoya Nakamura)
An estimated 50,000 bees and other insects died in a Wilsonville shopping center parking lot last week. A landscaper sprayed 55 flowering European linden trees with Safari pesticide on June 15. State officials confirmed the dinotefuran insecticide was responsible for the deaths. Hundreds of dead bees in Hillsboro are also being investigated.
"We're not trying to get it off the shelves, or trying to tell people to dispose of it, we're just telling people not to use it," said Bruce Pokarney, a spokesperson for the department of agriculture.
While Pokarney acknowledged it would be difficult to cite individual homeowners, he said licensed pesticide applicators would be violating Oregon regulations if they use dinotefuran-based insecticides on plants in the next 180 days.
The temporary ban only affects pesticide use that might harm pollinators, like bumblebees. Safari is one of the insecticides restricted by the Agriculture Department. Most of the restricted insecticides are used primarily for ornamental, not agricultural, pest control.
Dinotefuran use in flea collars, and ant and roach control will still be allowed.
The Department of Agriculture will reassess the temporary restriction after officials finish their investigation into the pesticide applications in Wilsonville and Hillsboro. These inquiries could take up to four months.
The Valent U.S.A. Corporation, which distributes Safari, could not be reached for comment, but the company released a statement earlier this week about the bee deaths.
"We are actively conducting outreach with our customers and industry partners to reinforce the importance of responsible use according to label guidelines," the statement said.
Dinotefuran is a member of a type of insecticides called neonicotinoids. Neonicotinoids can be broken down into two groups: the nitro-group and the cyano-group. Dinotefuran is a member of the nitro-group, which has been shown to be more poisonous to pollinators. The European Union issued a temporarily ban earlier this year on three other nitro-group neonicotinoids, which goes into effect this December.
The Washington state Department of Agriculture decided against banning the ornamental use of neonicotinoids earlier this month. Instead, the Washington department will "urge the U.S. Environmental Protection Agency to consider whether additional use restrictions are needed when the products are applied to ornamental plants."
The Portland-based Xerces Society, who originally reported the Wilsonville bee deaths to the Department of Agriculture, is working with a congressional office on legislation about pollinators and pesticide use, said Scott Black, Xerces' executive director.
"We hope that this is just the start, that now we can take a look at this entire class of pesticides called neonicotiniods and really scrutinize them for their potential impact on these beneficial insects," Black said.
--Elizabeth Case
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