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Here is an article on this subject
1.Genetically Engineered Crops in the Real World – Bt
Corn, Insecticide Use, and Honey Bees 2.Are Pesticides Behind Massive Bee
Die-Offs?
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1.Genetically Engineered Crops in the Real World – Bt
Corn, Insecticide Use, and Honey Bees Doug Gurian-Sherman 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
pests—AKA Bt corn—has 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.
Dead bees
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 seed—and
seed from more and more other crops like soybeans—is 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.
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2.Are Pesticides Behind Massive Bee Die-Offs?
Tom Philpott
Mother Jones, Jan 10 2012
For the German chemical giant Bayer, neonicotinoid
pesticides—synthetic derivatives of nicotine that attack insects' nervous
systems—are 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" segment—the one that includes neonics—is
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 honeybees—whose population has come under severe pressure
from a mysterious condition called colony collapse disorder—the 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
paper—published in the peer-reviewed journal Plos One—it'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 crop—corn—and 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 insists—and so far, the EPA concurs—that 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 seed—and also in adjacent fields that hadn't been recently planted. And
they found it in dandelion weeds growing near cornfields—suggesting 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 effect—what 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 things—though 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 bees—and 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.
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