This post was updated in May 2011.

Niwot, Colorado, beekeeper Tom Theobald has been concerned about the effects of pesticides on honeybee populations for some time, and that concern motivated him to release a November 2010 EPA memo relating to Bayer’s application to expand registration of clothianidin, a pesticide in the neonicotinoid class, to mustard and cotton crops.

In an article in Bee Culture, Theobald explains how he first began to investigate neonicotinoids, which are sprayed on seeds and persist in every part of the plant throughout its life cycle. In other words, the seed sprayed with one of these highly sophisticated pesticides will grow into a plant that has neurotoxins in its leaves and pollen, where bees (and the targeted insect pests) can be poisoned by them.

Along with other beekeepers, I have been concerned about clothianidin for some time, in part because it is not the first neonicotinoid to cause problems. Imidacloprid, the first, was registered in the U.S. in 1994 and was soon implicated in widespread bee kills. Several commercial beekeepers in North Dakota filed suit because of damage from imidacloprid used on sunflowers and similar damage in France from use on sunflowers led to a ban there in 1999. However it is still used without change in the U.S. France declined to even register clothianidin.

I became concerned about clothianidin in 2007 as the possible cause of a break in the Fall brood cycle I was seeing in my bees and in early 2008 I began digging into the facts surrounding its approval. (Source: “Do We Have a Pesticide Blowout?” Tom Theobald, Bee Culture, 7/12/2010, PDF available on the website of the Boulder County Beekeepers Association—scroll down to Articles)

In fact, clothianidin has never been properly approved. It was given conditional registration in 2003, but Bayer was required to conduct a study of the effect of the chemicals on bees throughout a full life cycle (about 2 months). The study was not even completed until 2006, and then it was conducted using canola plants in Canada, instead of corn plants, the crop most heavily sprayed with clothianidin in the United States. EPA considered the study to be sound, but the November 2010 memo released by Theobald shows that not everyone at EPA agrees with that assessment.

Since EPA seems to have repudiated the study on which the conditional registration was based, beekeepers and environmentalists thought the time was perfect to ask EPA to withdraw its registration of clothianidin. That letter, dated December 8, 2010, is also available on the Boulder County Beekeepers Association website, as is the 99-page memo.

What is conditional registration?

According to Theobald, conditional registration of a pesticide is granted for a variety of reasons, some of which are as minor as labeling issues, and some of which are serious, as in the possibility that neonicotinoids might cause massive bee die-offs. In summer 2010, Theobald asked EPA for a list of pesticides granted conditional registration and learned that 94 pesticides  have come onto the market since 1997, with more than two-thirds of them granted conditional registration.

I’d love to blame George W. Bush’s anti-science administration for all that, but I’d bet the EPA under Clinton was also guilty.

How is this restoration?

If this class of pesticides was banned, then perhaps bee populations would recover somewhat. It’s a big if, since viruses and mites have also been blamed for colony collapse disorder (CCD). Here’s Theobald’s take on it:

I think pesticides are the portion of the problem that can be most immediately addressed, without any new money, any new people, any new laws, and we may find that these viruses do play a role, but it’s like the polio vaccine, you know, we may find the vaccine and administer it to everyone and then tell the children to go out and play in heavy traffic. If we don’t solve these pesticide problems, these other things aren’t gonna matter. (Source: Radio interview with Tom Theobald, KGNU, 10/8/10; available on Boulder County Beekeepers Association website)

One undoubted bonus, in any case, would be that pollinators and people would no longer be serving as test subjects for pesticide makers. I find it infuriating that the EPA grants conditional registration at all.


The subject of pollinator die-offs is complex. For more information, try this article: “Leaked Document Shows EPA Allowed Bee-Toxic Pesticides Despite Own Scientists’ Red Flags,” Tom Philpott, Grist, December 10, 2010.

Thanks to Laura Tyler of Boulder Media Women for alerting me to this story.


Update from May 22, 2011: I received another email from Laura Tyler with a link to the following paper: “Widespread Immune Deficiency Disease in Wildlife: A Hypothesis.” It was written in April 2011 by retired Welsh scientist Rosemary Mason, MB, ChB, FRCA, and Palle Uhd Jepsen, former senior adviser in nature conservation and wildlife to the Danish Forest and Nature Agency. The link is on the website of the Boulder County Beekeepers Association.

Here’s a quote from the end of the paper:

There is evidence that immune compromise in wildlife is now widespread. A series of unrecognised pathogens are driving worldwide extinctions in a variety of species, including amphibians, bats, birds, invertebrates (and in particular, pollinators).

In other words, all those species are experiencing something like acquired immune deficiency syndrome (AIDS), which makes them vulnerable to a variety of diseases and conditions that kill them. The real cause of the problem, according to Mason and Jepsen, is the neonicotinoid pesticides that have been used with increasing frequency since the mid-1990s. These pesticides are sprayed on seeds and thus become an integral part of the plant.

Leave A Comment

  1. Laura Tyler December 15, 2010 at 11:37 am - Reply

    I agree, conditional registrations are infuriating.

    Regardless of what happened at the EPA under Bush, it appears that that a pro chemical industry bias holds sway at the agency today. Tom Philpott at asked an anonymous source at the EPA if the leaked memo would inspire the agency to take clothianidin off the market. The spokesperson “replied that clothianidin would retain its registration and be available for use in the spring.”

    This is just the beginning…

    Great reporting. Thank you.

  2. Beth Partin December 17, 2010 at 11:48 am - Reply

    It seems that bias has been growing since the 1990s.

  3. […] This is a story worth following. Tom Philpott at Grist has done some excellent reporting. Other fine reporting available at Wired, Fast Company and Restoration Nation. […]

  4. Laura Tyler April 14, 2011 at 10:33 am - Reply

    Thought you might be interested in this new paper that links what’s happening with amphibians to the neonicotinoid insecticides that are impacting honeybees.

    BTW, I was at the National Pesticide Forum on Friday and the mood there was positive. A bias-shift may be underway…

  5. […] wrote a related article in December 2010, which provides some background information on the neonicotinoids, the class of pesticides held responsible by the paper’s […]