Are Systemic Pesticides To Blame for Honeybee Colony Collapse?

Measuring bee population in a beehive

Measuring bee population in a beehive

Last week I began a series of articles about bee colony collapse disorder pointing out that about six or seven years ago beekeepers started to notice a massive disappearance of bees. Initially, many causes were considered, from pollution to disease, but the role of pesticides, particularly systemic pesticides, was downplayed and it was not until recently that researchers started digging deeper to explore the pesticide connection. As it turns out, the Environmental Protection Agency (EPA) had its own concerns about systemic pesticides but permitted a product to be marketed nonetheless.

The Problem With Systemic Pesticides

James Frazier, Ph.D, a professor of entomology at Penn State’s College of Agricultural Sciences, and other researchers and beekeepers is concerned that the EPA is not adequately evaluating pesticide interaction, sub-lethal impacts, and interaction with other stressors on honeybee fitness.  Like Tom Theobald, a Colorado beekeeper and one of the founders of the Boulder County Beekeepers’ Association, Professor Frazier criticized the EPA for using the same approach to evaluating systemic pesticides that is used for older generation pesticides. He explained to me in a recent interview that the EPA had sixteen years to develop a different protocol for evaluating systemic pesticides but the agency still relies on a risk-benefits analysis model it has used all along. Under the risk-benefits analysis, scientific evidence is only one of the factors considered when evaluating a pesticide for approval. The other factors include economic, technological, political, and social. Another serious problem with the EPA approval process is that ultimately it is the EPA administrators, not the EPA scientists, who make approval decisions.

By comparison, the European Union adopted the precautionary principle which, in essence, directs that action be taken to reduce risk from chemicals in the face of uncertain but suggestive evidence of harm to human health and the environment. While the system is far from perfect (see, for example, RoundUp and Birth Defects, Is the Public Being Kept In The Dark?, a report by international scientists challenging the European pesticide approval process for failing to consider independent scientific research and the lack of regulatory enforcement), there is, nonetheless, a formal process which allows for the removal from the market of chemicals suspected of causing harm, even when scientific evidence is insufficient, inconclusive or uncertain but preliminary scientific evaluation indicates that there are reasonable grounds for concern.

Systemic pesticides call out for a different system of approval since they differ in many respects from older generation pesticides.

Being one of the most widely used pesticides in the United States, systemic pesticides became popular in U.S. in 2000s and have increased with the increased planting of transgenic seeds (a.k.a. GMOs). “Unlike older pesticides that evaporate or disperse shortly after application, neonicotinoids are systemic poisons. Applied to the soil or doused on seeds, neonicotinoid insecticides incorporate themselves into the plant’s tissues, turning the plant itself into a tiny poison factory emitting toxin from its roots, leaves, stems, pollen, and nectar.”  With systemic pesticides, “the chemical is in the bloom. So bees searching for nectar now can come into contact with pesticides too.”

And they persist in the soil for longer than the older generation pesticides. Professor Frazier explained that systemic pesticides could remain in the soil anywhere between two to three years, and in some cases up to six years, depending on the nature of the soil and the chemical formulation of the pesticide.

Systemic pesticides are of a particular concern to beekeepers because they kill sucking and chewing insects by disrupting their nervous systems. While the routes of exposure have previously focused on contaminated food that is taken up by bees, new evidence is emerging that suggests additional ways in which bees are exposed to neonicotinoids. Recent studies performed in Italy suggest that bees become contaminated by insecticide (neonicotinoid) dust emission during foraging activity when they fly near a drilling machine at levels “sufficient to kill the bees.” Specifically, the researchers concluded that their trials “indicate that when a bee travelling towards a food source flies over a seeder that is sowing insecticide-coated maize seed, the bee may be exposed to a lethal dose of active ingredient, probably even in a single flight.” (Marzaro, et al., 2011; APENET Project, 2011).

The Role of the EPA

The chemical companies say that neonicotinoids are safe when properly applied and the EPA has been reactionary in its approach to this class of bee-killers. Based on internal memos that have now surfaced, there are even suggestions that the EPA administrators ignored or discounted the advice of its own scientists.

For example, in 2003, before clothianidin was approved, an internal the EPA memo demonstrates that government scientists had serious concerns about the impact of clothianidin on bees:

The possibility of toxic exposure to nontarget pollinators through the translocation of clothianidin residues that result from seed treatment (corn and canola) has prompted EFED [Environmental Fate and Effects Division] to require field testing that can evaluate the possible chronic exposure to honey bee larvae and queen. In order to fully evaluate the possibility of this toxic effect, a complete worker bee life cycle study must be conducted, as well as an  evaluation of exposure and effects to the queen.”

Despite these concerns, however, two months later and “after further consideration,” the EPA granted Bayer Cropscience, the maker of clothianidin, conditional registration “contingent on [Bayer] conducting the chronic honey bee study that evaluates the sublethal effects of clothianidin over time.” Many suspect that the EPA scientists granted conditional registration in response to internal pressure from the agency’s administrators. The EPA also deferred a strong label warning requirement “until after the chronic study has been reviewed.”

It should not go unnoticed that it is the chemical company that design the tests and performs its own research, not the EPA.

The chronic bee study became available only in 2007, even though the EPA initially asked for it to be completed eight months after clothianidin was conditionally approved. In the meantime, clothianidin was marketed and sold to farmers nationwide for use on corn, canola, soy, sugar beets, sunflowers, and wheat.

This has become a common tactic in the corporate playbook, get these products out there by whatever means possible, get agriculture hooked, and then convince farmers they can’t live without them. (Theobald, Do We Have A Pesticide Blowout).

When Bayer’s study became available many critics were dismayed that it was accepted by the EPA as “scientifically sound.” For starters, the study, consisting of only four bee colonies evaluated on a two-and-a-half acre plot. But, as Professor Frazier explained, bees can travel anywhere from 6 to 9 kilometers, i.e., up to 28,000 acres, from the apiary.

Tom Theobald called Bayer’s study a “mockery of science” and “bogus”- especially given the prior experience in France with imidacloprid, the predecessor to clothianidin, and the 2008 German bee die off, in which 99% the dead bees showed high levels of clothianidin. Likewise, Professor Fraizer noted that Bayer’s field study “was not a good test design.” Furthermore, Bayer’s study, much like other industry tests, was not subject to review by the independent scientific community so there is no independent verification of the company’s data.

Another deficiency of the study noted by Tom Theobald and others was the location of the study. Initially, the company was required to perform the field study in U.S., but the study was actually performed in Canada. Furthermore, Bayer was allowed to test on canola only, dismissing the EPA’s initial requirement that the study also include corn. This is significant since not only is canola less common than corn in U.S., canola is also predominantly grown in one state, North Dakota, while corn planting is more ubiquitous, with major production happening in the Corn Belt and less intensive operations happening in other states around the country.

David Hackenberg, another beekeeper, was also concerned about the connection of bee die-offs to corn. Hackenberg told FastCompany that bee die-off seemed to follow corn crop plantings so much that “you can follow the trail of this stuff to where bees are collapsing.”

In 2010, when Bayer sought to expand the use of clothianidin on cotton and mustard seed, the EPA revoked Bayer’s prior study–the one the agency considered “scientifically sound” in 2007 — and required “another field study … to evaluate the effects of clothianidin on bees through contaminated pollen and nectar.” It was noted by a consumer and environment watchdog Beyond Pesticide that “while the [2007] study may contain ‘some’ useful information, as stated by the EPA, it does not contain ‘required’ information necessary to registration and the protection of bees from a systemic pesticide that moves through the treated plant.”

The EPA’s 2010 decision noted that:

Acute toxicity studies to honey bees show that clothianidin is highly toxic on both a contact and an oral basis. … information from standard tests and field studies, as well as incident reports involving other neonicotinoids insecticides (e.g., imidacloprid) suggest the potential for long term toxic risk  to honey bees and other beneficial insects. An incident in Germany already illustrated the toxicity of clothianidin to honeybees when allowed to drift off-site from treated seed during planting.

And the EPA suggested the following strongly worded label be used:


The full suggested text of the EPA Clothianidin label from internal memorandum.

This compound is toxic to honey bees.  The persistence of residues and potential residual toxicity of Clothianidin in nectar and pollen suggests the possibility of chronic toxic risk to honey bee larvae and the eventual instability of the hive.

Despite the EPA’s belated acknowledgment that Bayer’s study was inadequate, the pesticide remains on the market. A review of the company’s labels and the manufacturer’s safety data sheets for clothianidin suggests that there is no labeling that would warn U.S. growers regarding the pesticides’ impact on bees despite suggestions from the EPA to the contrary.

  • Shubbee

    The greed for the almighty dollar will destroy us in the end…. amazing isn’t it?  How many harmful products the EPA has ok’d over scientific negatives…..  Have ABSOLUTELY NO RESPECT/TRUST for EPA!!!!

  • GMO Journal

    Indeed. We like what Tom Theobald told us during an interview. This Colorado beekeeper said that “corporatism,” which he defined as the “takeover of gov by industry” –has recently entered his vocabulary.
    When you have industry folks working at gov agencies and occupying decision making posts (and who often go back and forth b/w gov & idus positions), and when the lobbyists are exerting so much pressure to the point that people’s voices and concerns get drowned out, it is easy to see how Mr. Theobald’s words ring true. 

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