Tag Archives: Pesticides

Powerful Poisons Interact to Attack the Industrious Honey Bee

In and of themselves pesticides may not be the sole culprits of Colony Collapse Disorder (CCD).  Could understanding the synergisms between these chemicals help solve the mystery of CCD?

Beeswax Candles--Courtesy of Roberrific/Flickr Creative Commons

The snowstorm is looming. Tom Theobald, Boulder Colorado bee keeper, will retire to his honey house to watch the early winter flakes dance in the cold air.  There, he will be “doing a run of hand-dipped beeswax candles.”  After all, when the power goes out he always reverts to the work of small and industrious insects, the honey bees, whose burning wax will shed light in his cabin.  Theobald can enjoy the process of making beeswax candles and can survive the exit of the bees from his life were his colonies to continue to wane because of CCD. Commercial bee keepers, as he says, cannot–as they are the most affected economically by the decline of the bees.   While one may be able to pinpoint the role of one specific pesticide in CCD,  the mystery of CCD is intensified as the interactions between the many chemical ingredients used in 21st century American agriculture become apparent.

Theobald takes my call on November 1, 2011, just before the storm.   This time we don’t focus merely on the systemic pesticide chlothianidin, but rather discuss the complexity of synergisms, the interactions of various pesticides on the health of the hive and the bee.  Theobald confides that fungicides “only entered his consciousness just recently,”  as part of a larger investigation into neonicotinoids, nicotine-derived pesticides.

As I mentioned in an earlier blog, fungi are crucial to the health of the hive.  They break down the pollen inside the hive.  As Theobald points out, fungicides disrupt the bee’s intestinal flora.  Bee bread is only a partly digested product that needs intestinal flora to be metabolized.  Fungicides, instead, “decrease the microbial diversity of the bee’s food source” according to David Doll, Farm Advisor for the University of California Cooperative Extension.  However, since fungicides, like pesticides, are required for a profitable crop, they become an integral element of the pollination process and therefore pose health risks to honey bees.

According to David Doll, fungicides are generally applied around or at bloom when they will adhere to the pollen. Their application during bloom should, therefore, be regulated.    Unlike Europe that errs on the side of caution, banning pesticides until they are proven not to be harmful, in the US there is, as reporter for the GMO journal Deniza Gertzberg points out, “no accurate and complete picture of what pesticides are used, where and in what amounts, or the accurate measures of just what the maximum exposure is in agricultural or urban settings on blooming plants.”

Jan Knodel, Extension Entomologist for North Dakota State University presents guidelines for reducing pesticide poisoning to bees:

As bees work the hardest during bloom, they will thus inevitably bring back the fungicide-laced pollen to the hive where they will store it to be eaten later or where it is eaten immediately, its nutritional value having been altered by the fungicides.

Theobald focuses on the fungicide boscalid in particular.  Introduced in the USA in 2003, boscalid, the active ingredient in the fungicide emerald, is a respiration inhibitor within the fungal cell.  It is highly successful in fighting fungal diseases in fruits, vegetables and grapes that are used for wine.

In the non-committal language of the EPA boscalid is “practically nontoxic to terrestrial animals and is moderately toxic to aquatic animals on an acute exposure basis.”  However, according to the PAN pesticides database,  “population-level effects on honeybees may occur even if a pesticide has low acute toxicity. […] certain pesticides interfere with honeybee reproduction, ability to navigate, or temperature regulation, any of which can have an effect on long-term survival of honey bee colonies.”

A recent study by James Frazier, professor of entomology at Penn State’s College of Agricultural Sciences highlights the magnitude of the problem of pesticides like boscalid making their way into the bee’s hives and lacing their food with poison: “on average six different pesticides, and in some cases, as many as 39 pesticides were found in hives across the United States.”   This  study focuses not on one specific pesticide but rather on the presence of multiple pesticides, in fact “98 pesticides and metabolites detected in […] bee pollen alone,” suggesting  the need for research on the synergisms between pesticides that might underlie the demise of the bees.

Theobald echoes the need for research on the potentially lethal synergisms of various pesticides on bees, as he refers to a 2010 report by the Cornell University Cooperative Extension stating the need for such studies, as “some fungicides may affect a bee’s ability to tolerate other pesticides.”

It is not only about chlothianidin.  It is not merely about boscalid.  According to Gertzberg, over 1,200 active ingredients are distributed among 18,000 products nationwide and are now integral to the honey bees’ landscape.  The complexity of the demise of the bees lies in the synergisms between these chemicals.

Accounting for his Losses in Colorado: A Honey Farmer Looks to Neonicotinoids

According to Tom Theobald, a Boulder Colorado bee keeper, chlothianidin is causing the decline of bee colonies. How and when did the bees get poisoned?

“These neonicotinoids are huge.  This is the insecticidal equivalent of plutonium,” said Tom Theobald, in a phone interview on October 26, 2011.  In my last blog post, I asked whether chlothianidin was responsible for CCD.  To some, to Tom Theobald, there is no doubt.

Long before CCD became a national story in 2006, Tom Theobald had been experiencing unusual losses among his honey bee colonies.  As early as the winter of 1995, with the appearance of the varroa mites, the Colorado bee keeper’s colonies had suffered serious declines, their hives being abandoned, teeming with honey that other bees failed to forage.  The varroa mite was considered the culprit at the time.  As its impact diminished, the winter losses, however, continued to escalate.  This escalation coincided, in Theobald’s view, with the introduction of the pesticide Imidachloprid.

Imidacloprid, first registered for use in the US by the EPA in 1994 and banned in France  since 2004, in Germany and Italy since 2008 , is a neonicotinoid that systematically penetrates the plant and is used to control sucking and chewing insects.  It penetrates the insect’s nervous system, blocking its neural pathway that, in insects, is more abundant than in warm-blooded animals.  The insect that sucks on the treated crop will become paralysed and die.  Imidacloprid is in fact known to be highly toxic to bees.   In 2003, when its patent ran out, it was replaced by another neonicotinoid, chlothianidin.

On his Colorado honey farm, Tom Theobald set out like Sherlock Holmes to try to explore the mystery of his disappearing bees.   His colonies had ended the summer strong: “the brood nest was the size of a basketball.”  Yet somehow, by October, the brood nest had suffered a precipitous decline in size – “it had become the size of a softball.”  The colony of 30,000 bees had declined to 3,000.  Puzzled by this decline and given the absence of varroa mites, he figured that the queen must have either stopped laying, stopped laying viable brood, or that the larvae were dying.  This period in the fall, when the colony is producing the winter brood, is a crucial one: there must be a critical mass of bees to protect the colony, to serve as the outer layer, the “sacrificial blanket” as it were of the hive that keeps the dormant bees warm throughout the cold winter months.  With the break in the brood cycle, there was no winter layer and the colonies simply collapsed.

Bee colonies--Courtesy of Avalanche Looms/Flickr Creative Commons

Why this sudden arrest in procreative activity?  Theobald looked over to the surrounding corn fields.  The corn pollen contained the neonicotinoid chlothianidin known to compromise the fertility of the queen and the viability of the brood, as explained in the PAN pesticides Database: “Population-level effects on honeybees may occur even if a pesticide has low acute toxicity. For example, certain pesticides interfere with honeybee reproduction, ability to navigate, or temperature regulation, any of which can have an effect on long-term survival of honeybee colonies. The neonicotinoids, pyrethroids and keto-enol pesticides are some types of pesticides causing one or more of these effects.”

The bees, Theobald explained in his interview, will store pollen and not use it as long as there is fresh pollen available.  Thus the pesticide-laden corn pollen culled in the summer got “stored in the pantry” until the supply of fresh pollen ran out.  At that point, around October, the neonicotinoid of the stored pollen attacked the queen’s reproductive system. 

When the summer bees die, having worked themselves to death, winter bees normally replace them.  Now Theobald’s summer bees had died and there were no winter bees to take over and repopulate the colony.

Chlothianidin will enter its tenth year on the market and it has yet to meet the requirements of registration.  When chlothianidin was approved in 2003, there was no pressing insect scourge, Theobald points out, that required immediate approval of the pesticide.  What was running out was Bayer‘s, the manufacturing company’s, patent for Imidacloprid.  So today, as he says, “we are subjected to all this damage not to protect the world against an insect but to protect Bayer’s market share.”

"We want bees, not toxic chemicals"--Courtesy of Avaazorg/Flickr Creative Commons

Given the risks and the damages, is there then any advantage to the use of these neonicotinoids? No.   Not only is it killing the bees, according to Theobald, but it is poisoning the soil: “If you are a farmer and you get on this boat, what does your soil look like in five years?  You don’t have soil.  You have real estate.”  As chlothianidin has a half life of nineteen years, it takes over 100 years for the soil to purge itself of the chemical.  While the effect on the bees’ neural receptors is cumulative and irreversible, Theobald admonishes “it goes way beyond the bees.”

The Disappearance of the Buzz: is Chlothianidin the Culprit?

Chlothianidin, a neonicotinoid, may be one of the causes of Colony Collapse Disorder.     Why is it still on the market?

“Can anyone believe it is possible to lay down such a barrage of poisons on the surface of the earth without making it unfit for all life?”  Rachel Carson’s call to arms is as current today as it was in 1962.  The use of pesticides in America’s farmlands today continues to create concern regarding the ease of legalization and laxness of regulation.

Clothianidin and CCD (Photo courtesy of Timw_brap)

The disappearance of bees across the globe remains an open question, although clear attention is being paid to pesticides as potentially contributing factors.   The connection of pesticides to Colony Collapse Disorder (CCD) is an example of both the lack of regulation and of supervision at the federal level when it comes to marketing and distributing highly noxious chemicals.  The story of one pesticide in particular, however, highlights the recognition that, as Paul Brooks, Carlson’s editor, says: in our “overorganized and overmechanized age, individual initiative and courage still count.”

While scientists agree that CCD is “a syndrome caused by many different factors, working in combination or synergistically,” research continues to focus on pesticides.  One pesticide in particular is raising a buzz in the bee community as well as on the federal level.  The case of chlothianidin, a neonicotinoid (considered a “green” pesticide because it is derived from nicotine), underscores the difficulties encountered in challenging large manufacturing companies and the EPA.

This nicotine-derived pesticide, that the EPA registered conditionally in 2003, is a systemic pesticide.  It is, as Tom Theobald, a Colorado beekeeper, points out, “incorporated into the system of the plant when the seed germinates.”  It is thus more appealing to the farmer.  Spraying cycles are less frequent and the pesticide kills all unwanted pests: “any insect which chews or sucks on the plant ingests the pesticide and dies.”  The problem here of course lies in selectivity: how does one save the good bugs from the bad bugs?  How does a bee keeper keep his bees from pollinating pesticide-treated corn in the hundreds of acres surrounding their beehive?

The answer is quite simple.  He cannot.  We cannot.  As Dave Hackenberg,  Pennsylvania’s largest bee keeper explains in a phone interview on October 17, 2011:  “you can’t build a fence around [the bees]  like you would with a cow […] The honeybees are going to fly for miles in each direction.  The colonies are going to bring [neonicotinoids] home.”  The problem with neonicotinoids is a complex one, as Hackenberg suggests in his interview with me:

In researching the effects of one of the neonicotionoids, chlothianidin, Theobald points out that two thirds of the bee colonies of Baden-Wurttemberg, Germany, died in May 2008, 99% of them showing high levels of chlothianidin.  It took Germany only two weeks to ban the chemical.  Soon Italy and Slovenia followed suit.

So why is the United States lagging in its response to banning it?  In researching the history of chlothianidin Theobald revealed the EPA scientists’ comments of February 2003: “This compound is toxic to honey bees.  The persistence of residues and the expression of chlothianidin in nectar and pollen suggest the possibility of chronic toxic risk to honey bee larvae and the eventual stability of the hive.”

And yet the pesticide was approved by the EPA for use.  In April 2003, the EPA gave a registration to Bayer, the manufacturing company, that was conditional on its completion of a chronic honey bee study recommended by EPA scientists that would evaluate and confirm the possibility of toxicity.

In 2008, the results of the Bayer study, held under wraps since 2006, were made public.  They showed bees had been unaffected by the use of chlothianidin.  As Tom Theobald points out in “Pesticide Blowout,” “four colonies of bees were set in the middle of one hectare [..] of canola planted from treated seed, with the bees free to forage over thousands of surrounding acres in bloom with untreated canola, which they surely did.  What do you think the results were? They were exactly what Bayer wanted, of course.”

On December 8, 2010, representatives from several beekeeping associations wrote a letter to the EPA highlighting the “imminent hazard” posed by chlothianidin and requesting that the EPA issue a “stop use order.”   The EPA responded in February 2011 that the “imminent hazard” was not supported by data, evidence, or explanation: there was no case for issuing a “stop use order.”

The outcome: the pesticide is still on the market, waiting until 2012 for the EPA to assess the hazard it poses to honey bees. In Europe, the ban seems to have been rapid and efficient.  In the United States, the battle to ban chlothianidin remains an uphill one.