Target shoppers in Wilsonville, Oregon found a tragedy in the parking lot as tens of thousands of of bumble bees were found dead and dying on the pavement, along with honey bees and ladybugs. Shoppers notified Rich Hatfield, a conservation biologist with the Portland-based Xerces Society of Invertebrate Conservation, who went to the scene to investigate.

Because the bees were mostly clustered under dozens of European linden trees, the organization believes the cause of the deaths likely involves acute pesticide poisoning or a poisonous species of European linden tree.

© Rich Hatfield of The Xerces Society 2013 “They were literally falling out of the trees. To our knowledge this is one of the largest documented bumble bee deaths in the Western U.S. It was heartbreaking to watch," says Hatfield in a press release from the Xerces Society.

The Oregon Department of Agriculture arrived to take samples from the trees to determine if a pesticide was used. The Xerces Society recommends that if it is due to poisonous linden trees, the trees should be removed immediately and replaced with a nontoxic species. “On the other hand," said Scott Hoffman Black, Executive Director at the Xerces Society, "if pesticides are the cause, we need to spotlight this as a real-world lesson in the harm these toxic chemicals are causing to beneficial insects. It would be especially alarming to find out whether pesticides are the cause in this case because the linden trees are not even an agricultural crop. Any spraying that happened would have been done for purely cosmetic reasons.”

© Rich Hatfield of The Xerces Society 2013

Update: According to the International Business Times:

Oregon officials say preliminary results point to an insecticide that was used on the nearby European Linden trees. The trees were sprayed with a pesticide called Safari to kill aphids, an insect that destroys plants and vegetation. Safari is part of a group of pesticides called neonicotinoids that are known to kill pollinators such as bumblebees, Associated Press reports. The investigation is still under way. If the pesticide is the confirmed cause and it wasn’t used according to the label instructions, civil penalties could be handed down ranging from $1,000 to $10,000 per violation for gross negligence or willful misconduct, Dale Mitchell, program manager in the Agriculture Department's pesticide compliance and enforcement section, told AP.

And Mother Nature Network writes:

"[The landscapers] made a huge mistake, but unfortunately this is not that uncommon," said Scott Hoffman Black, executive director of the Xerces Society. "Evidently they didn't follow the label instructions. This should not have been applied to the trees while they're in bloom."

Yet ODA was not ready to pin the blame so quickly.

"I don’t think we’re there yet," said ODA Communications Director Bruce Pokarney. "We’re looking at any other pesticide applications that might have taken place in the area that might have come into play. Until we get all that figured out, we stop short of saying this is the culprit or the likely culprit. It’s one of the possibilities we’re looking at. A very strong possibility."

It couldn’t have come at a more poignant, or ironic, time. The United States Department of Interior designated this year’s National Pollinator Week as June 17-23, 2013. Every year, the week serves to highlight the invaluable services provided by our pollinators, including bees, birds, butterflies, bats and beetles. One out of every three bites of food we take comes from foods that are dependent on pollinators, so we really can’t afford to lose more.



UPDATE: Cause of deaths confirmed, count rises to 50,000 dead bees

From The Oregonian: