Largest Mass Bumble Bee Death on Record

On the eve of National Pollinator Week the largest mass bumble bee death on record occurred in a Wilsonville, Oregon parking lot. The estimated 50,000 bumble bees found dead in the Target lot had foraged on some fifty-five ornamental linden trees, confirmed by the Oregon Department of Agriculture to have been sprayed with the insecticide dinotefuran, trade name Safari. According to an article from Oregon Public Broadcasting, “The chemical application was intended to kill aphids because they produce a honeydew substance that drops from the trees onto parked cars.” This incident is an example of insecticide misapplication with devastating consequences.

A broad-spectrum insecticide, dinotefuran is in the neonicotinoid chemical class. The supplemental label for Safari in particular lists the many different types of application, from foliar and broadcast sprays to soil application and trunk sprays in trees and large shrubs. Regarding application to ornamental plants and forestry, the supplemental label states that “for trees in forests that are pollinated by bees or other invertebrates, make applications post-bloom.” The Material Safety Data Sheet for Safari states that “Dinotefuran Technical is highly toxic to bees.” In the wake of this bumble bee kill, I feel compelled to revisit Rachel Carson’s influential book Silent Spring. First published in 1962, this book raised public awareness of the widespread usage of pesticides with prolonged breakdown times, DDT(dichlorodiphenyltrichloroethane) in particular, and the resultant harmful effects on the natural world. In the second chapter, entitled “The Obligation to Endure,” Carson writes:


Only within the moment of time represented by the present century has one species – man – acquired significant power to alter the nature of his world. During the past quarter century this power has not only increased to one of disturbing magnitude but it has changed in character. The most alarming of all man’s assaults upon the environment is the contamination of air, earth, rivers, and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable; the chain of evil it initiates not only in the world that must support life but in living tissues is for the most part irreversible. In this now universal contamination of the environment, chemicals are the sinister and little-recognized partners of radiation in changing the very nature of the world – the very nature of its life.

Carson’s thorough research of and passion for her subjects as well as a succinct and accessible writing style resulted in a New York Times best-seller that acted as a catalyst for the federal ban of DDT in 1972. I focus on this excerpt to provide a reminder that chemical applications can have irreversible consequences, not to equate dinotefuran with DDT. Dinotefuran is by no means as persistent in the environment as DDT which has a half-life of up to 15 years or more according to the Environmental Protection Agency (EPA). According to the EPA dinotefuran has a half-life at minimum of 1.8 days and at maximum 50-100 days. The lethality of dinotefuran is clear, however, from its misapplication on ornamental lindens in Wilsonville, Oregon that resulted in the loss of 50,000 bumble bees and in turn an estimated 300 or more wild bumble bee colonies.

Now is the time to reevaluate our need for insect control on ornamentals. The devastation to the wild bumble bee populations around Wilsonville, Oregon is not soon to be recovered and will result in an untold decrease in wildflower seed-set which in turn feeds birds and small mammals. I would bet, however that the 2014 aphid population on those lindens will be robust, considering their capacity to reproduce asexually. To learn more about the incident and what you can do to help, please visit the Xerces Society for Invertebrate Conservation. The linked article, “Scientists Call for an End to Cosmetic Insecticide Use After the Largest Bumble Bee Poisoning on Record,”, provides the latest facts on the bumble bee kill as well as recommendations from the Xerces Society for municipalities, homeowners, nursery and hardware stores, and the federal government that, if followed, could aid in the prevention of further bee deaths as a result of foraging visits to insecticide-treated ornamentals. Here’s a quick look at the Xerces Society recommendations for homeowners:

For homeowners

  • Do not buy products that contain neonicotinoids. A list of products can be found at
  • Check to see if you have these products in your garage or garden shed. If so, do not use them. Make sure you dispose of them properly or take them back to the store where you bought them.
  • When buying plants for your yard, ask if neonicotinoids have been used on them. If staff cannot tell you, shop somewhere else.

Blog Citations:

  • Carson, R. (2002). Silent Spring. Houghton Mifflin Harcourt, 2002. Google Books. Web. 30 June 2013.
  • Staff, FOX 12. “Pesticide banned following 50,000 bee deaths.” 27 June 2013. Web. 30 June 2013.
  • The Xerces Society. “Pesticide Causes Largest Mass Bumble Bee Death on Record.” 21 June, 2013. Web. 30 June 2013.



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