Bt corn, insecticide use, and honey bees
2.Are Pesticides Behind Massive Bee Die-Offs?
1.Genetically Engineered Crops in the Real World Bt Corn, Insecticide Use, and Honey Bees
Union of Concerned Scientists, January 10 2012
One of the most frequently mentioned benefits of genetically engineered crops is a reduction in chemical pesticide use on corn and cotton. These chemicals typically kill not only pest insects but also beneficial insects that help control pests or pollinate crops. They may also harm other friendly organisms like birds.
But in reality, corn engineered to kill certain insect pestsAKA Bt cornhas mainly resulted in the replacement of one group of chemical insecticides with another. Previously, corn may have been sprayed, or soil treated with chemical insecticides to control several insect pests, especially corn rootworm. Bt has largely eliminated (at least for the time being) the demand for insecticides to control rootworm or European corn borer.
But those who tout the benefits of GE fail to mention that today virtually all corn seed is treated instead with chemical insecticides called neonicotinoids to ward off several corn insects not well controlled by Bt toxins. And while almost all corn is now treated with insecticide via the seed, substantial amounts of corn went untreated by insecticides prior to Bt. For example, corn alternated (rotated) with soybeans from year to year usually needed little or no insecticide treatment, and only five to 10 percent of corn was sprayed for corn borers.
A new publication by several academic entomologists on the impact of neonicotinoid insecticides on honey bees shows that such seed treatment may be having serious repercussions. Previous research has linked neonicotinoids to bee deaths as a possible contributor to colony collapse disorder, which is wreaking havoc on bees across the United States.
The new research is important in showing that when neonicotinoid insecticides are used as seed treatments, they can migrate through the soil or through the air in dust to other plants near (or in) corn fields, like dandelions, which honey bees prefer as a pollen source. It was already known that this type of insecticide can travel through the plant as it grows, and this study also shows corn pollen contaminated with this insecticide and substantial corn pollen use by honey bees.
Importantly, the amount of the insecticide found in and around corn fields is near the range known to kill honey bees, and dead bees collected near treated fields contained insecticide residues. It is also known that sub-lethal doses of these insecticides can disorient bees, and may make them more susceptible to pathogens and parasites.
There are a few pieces of the puzzle that still remain to be put into place, but it is looking likely that neonicotinoid seed treatments are harming U.S. honey bees.
Let's get real
Other research indicates that corn seed treatment is harming other types of beneficial insects. An extensive study in the U.S. Northeast on many types of beneficial beetles that are found in corn fields showed that neonicotinoid seed treatments likely harmed several of these species, although other species may fill in. This study was limited to beetles, did not include other beneficial insects, spiders and mites, and did not examine the implications for crop damage. Other research has shown that reductions in beneficial organisms can result in decreased crop yields.
In general, current data suggests that the new, ubiquitous seed treatments that have accompanied Bt corn are just as harmful as the insecticides they are replacing.
And it illustrates that the impacts of GE technology must be considered more broadly than just direct harm from an engineered gene or protein. As the authors of one of the studies wrote: "Field experimentation must consider the effects of these broader systems for realistic evaluation of currently deployed transgenic crops."
University of Illinois entomologist Mike Gray, an expert on corn rootworm, summarized the state of U.S. corn production in a recent research article: "The current lack of integration of management tactics for insect pests of maize in the U.S. Corn Belt, due primarily to the escalating use of transgenic Bt hybrids, may eventually result in resistance evolution and/or other unforeseen consequences."
It is not incidental or coincidental that corn seedand seed from more and more other crops like soybeansis being treated with insecticides. It is a consequence of the susceptibility of our overly-simplified, biologically-pauperized agricultural system, which relies on piecemeal pest control approaches like Bt and chemical insecticides rather than ecologically based systems that greatly reduce the opportunities for pests to get a foothold.
So, why not GE AND agroecology ?
Some vocal advocates of GE have acknowledged that we need to use better, ecologically based agriculture practices, but maintain that we should integrate GE into those systems. Such an approach would likely improve the sustainability of GE pest control. But how would it advance truly sustainable agriculture?
In healthy agro-ecosystems, there is usually limited need for these types of pest control, and in most cases, that need can be met through breeding at much less expense than GE. The fact is that GE seed is expensive (because GE research and development is very expensive). And the large seed companies have a near monopoly on this technology, so they can jack up seed prices even further. Why should farmers be saddled with these unnecessary costs when cheaper technologies will work in the large majority of cases?
As I have written before, GE may occasionally have a useful role, and may sometimes provide real benefits. But in a sensible agriculture system it is not clear that it is really needed, or worth the cost.
(Thanks to Chuck Benbrook at the Organic Center for alerting me to the new article on bees and neonicotinoid insecticides)
About the author: Doug Gurian-Sherman is a widely-cited expert on biotechnology and sustainable agriculture. He holds a Ph.D. in plant pathology.
2.Are Pesticides Behind Massive Bee Die-Offs?
Mother Jones, Jan 10 2012
For the German chemical giant Bayer, neonicotinoid pesticidessynthetic derivatives of nicotine that attack insects' nervous systemsare big business. In 2010, the company reeled in 789 million euros (more than $1 billion) in revenue from its flagship neonic products imidacloprid and clothianidin. The company's latest quarterly report shows that its "seed treatment" segmentthe one that includes neonicsis booming. In the quarter that ended on September 30, sales for the company's seed treatments jumped 28 percent compared to the same period the previous year.
Such results no doubt bring cheer to Bayer's shareholders. But for honeybeeswhose population has come under severe pressure from a mysterious condition called colony collapse disorderthe news is decidedly less welcome. A year ago on Grist, I told the story of how this class of pesticides had gained approval from the EPA in a twisted process based on deeply flawed (by the EPA's own account) Bayer-funded science. A little later, I reported that research by the USDA's top bee scientist, Jeff Pettis, suggests that even tiny exposure to neonics can seriously harm honeybees.
Now a study from Purdue University researchers casts further suspicion on Bayer's money-minting concoctions. To understand the new paperpublished in the peer-reviewed journal Plos Oneit's important to know how seed treatments work, which is like this: The pesticides are applied directly to seeds before planting, and then get absorbed by the plant's vascular system. They are "expressed" in the pollen and nectar, where they attack the nervous systems of insects. Bayer targeted its treatments at the most prolific US cropcornand since 2003, corn farmers have been blanketing millions of acres of farmland with neonic-treated seeds.
No one disputes that neonics are highly toxic to bees. But Bayer insistsand so far, the EPA concursthat little if any neonic-laced pollen actually makes it into beehives, and that exposure to tiny amounts has no discernible effect on hive health. Bayer also claims that bees don't forage much on corn pollen.
The Purdue study calls all of this into question. The researchers looked at beehives near corn fields and found that bees are "exposed to these compounds [neonics] and several other agricultural pesticides in several ways throughout the foraging period." Contradicting Bayer's claim that bees don't forage much in cornfields, they found that "maize pollen was frequently collected by foraging honey bees while it was available: maize pollen comprised over 50% of the pollen collected by bees, by volume, in 10 of 20 samples." They detected "extremely high" levels of Bayer's clothianidin in the fumes that rise up when farmers plant corn seed in the spring. They found it in the soil of fields planted with treated seedand also in adjacent fields that hadn't been recently planted. And they found it in dandelion weeds growing near cornfieldssuggesting that the weeds might be taking it up from the soil.
Most alarmingly of all, they found it in dead bees "collected near hive entrances during the spring sampling period," as well as in "pollen collected by bees and stored in the hive."
Now, neonic pesticides likely have two separate effects on bees: an acute one during spring corn planting, when huge clouds of neonic-infested dust rises up, at doses that kill bees that come into contact with it. Those population losses weaken hives but don't typically destroy them. And then there's a gradual effectwhat scientists call "chronic"when bees bring in pollen contaminated at low levels by neonicotinoids. Research by the USDA's Pettis suggests that even microscopic levels of exposure to neonics compromises bees' immune systems, leaving hives vulnerable to other pathogens and prone to collapse.
The EPA has thus far relied on Bayer-funded research to maintain its registration of clothianidin even after a leaked document in late 2010 showed that its own staff scientists found Bayer's research to be shoddy. The agency ignored the ensuing controversy and once again let farmers plant seed treated with Bayer's concoction. The Purdue researchers report that "virtually all" of the vast US corn crop is now planted with seed treated with Bayer's dodgy pesticide, and the technology is rapidly spreading to the other most prodigious US crops: soybeans, cotton, and wheat. Now, ahead of the 2012 growing season, we have peer-reviewed, USDA-funded research that bluntly challenges Bayer's claims and implicates it in colony collapse disorder. Will the EPA look the other way while tens of millions of acres are poisoned for the nation's besieged honey bees?
Frankly, quite probably so. Bees can't organize political campaigns, of course, and the beekeeper lobby doesn't wield much influence in the grand scheme of thingsthough Pesticide Action Network is working hard to amplify their voice. Bayer, meanwhile, is a paid-up member of Croplife America, a powerful agribusiness interest group that the Obama administration won't likely want to tangle with heading into an election. Bad news for beesand bad news for the ecosystem of which they're such a vital part: ours.
Tom Philpott is the food and ag blogger for Mother Jones.