GMO Myths and Truths

events to take place between an infecting virus
and GM viral genes in the crop, thereby increasing
the risk of new, mutated, and potentially more
virulent strains of virus being produced. 185
Such viral mutation with increased virulence
has been shown to occur under laboratory
conditions. 186,187
To date only two GM crops engineered with
genes from viruses have been commercialised: a
variety of squash grown in the USA and Mexico, 188
189 and papaya cultivated in Hawaii. 190 There are
no reports of any investigations to see if any new
viral strains have arisen by recombination in these
two crops. Interestingly, and quite unexpectedly,
although the GM squash was resistant to viral
infection, it was found to be prone to bacterial wilt
disease following attack by beetles. 191
Conclusion to Section 5
Most of the benefits for farmers and the
environment claimed for GM crops are either
exaggerated or false. For example, contrary to
frequent claims, GM crops have not increased
intrinsic yield. Crop yields have increased over
the past decades, but this is due to successes in
conventional breeding, not GM traits.
Neither have GM crops decreased pesticide
use. The adoption of GM Bt maize and cotton
has resulted in a slight decrease in the volume of
insecticide sprays, but this decrease is likely to
be unsustainable as pests gain resistance to the
Bt toxins and secondary pests take over. Also,
the reduction in insecticidal sprays is dwarfed by
the massive increase in herbicide use caused by
the adoption of GM herbicide-tolerant crops. The
adoption of these GM crops has caused farmers to
spray 383 million more pounds (174 million kg)
of herbicides than they would have done in the
absence of GM herbicide-tolerant seeds.
This increase is largely due to the spread of
weeds resistant to glyphosate, the herbicide most
commonly used on GM crops. As a “solution” to
the problem of glyphosate-resistant weeds, biotech
companies have developed crops engineered to
tolerate several different herbicides, including
5.12.5. Overall assessment of the risks
of HGT by the above methods
HGT events of all types are of very low probability of
occurrence. The method with the highest probability
of occurring is DNA uptake by bacteria in either
the environment or the digestive tract. There is
good evidence that this has already happened in the
intestinal bacteria of humans who consume GM soy.
The other scenarios are of significantly lower
probability. However, given the extremely wide
distribution of GM crops and their intended use
over decades, these low probabilities translate
into the likelihood that HGT events could actually
occur even via the mechanisms that are expected
to take place at lower probabilities.
Therefore, the negative impacts and risks
associated with HGT must be taken into account in
considering the overall biosafety of any GM crop.
potentially even more toxic herbicides such as
dicamba and 2,4-D (an extremely toxic ingredient
of Agent Orange). The resulting chemical treadmill
only benefits the GM seed companies, which profit
from each failure of their technologies because the
failure creates a new opportunity for them to sell
more chemicals in increasingly complex mixtures.
Claims for the environmental friendliness of
the no-till farming system as practised with GM
herbicide-tolerant crops are also unjustified.
Glyphosate over-use is also causing other
problems for farmers, such as reducing crop
vigour by making soil nutrients unavailable to
crops and causing or exacerbating plant diseases
that impact yield. Manufacturer claims that
glyphosate/Roundup is an environmentally
benign herbicide with low toxicity have proved
to be false, with a growing number of studies
showing that it persists in the environment and
has toxic effects, in addition to studies showing
that it is toxic to humans and causes birth defects
and cancer.
Claims of reductions in insecticide use through
Bt crops are suspect when it is considered that
the entire GM plant is an insecticide. Also, Bt
crop technology is being undermined by the
GMO Myths and Truths 94