"GM crops have higher yields,
improved performances, and greatly reduce the use of agrochemicals. Farmers
like them because they increase income." Lim Li Ching and Jonathan
Matthews debunk these myths, documenting failures of GM crops around the world.
Lower Yields
Thousands of controlled trials have shown
significantly decreased yields with GM crops.
A study based on 8,200 trials of soya
varieties in US universities in 1998 [1] reports yield drags between top RR
varieties and top conventional varieties averaging 6.7%. In some areas, best
conventional varieties produced yields on average 10% higher than RR varieties
sold by the same seed companies.
In May 2000, results of a two-year study by
Nebraska University’s Institute of Agriculture and Natural Resources showed RR
soya yielded 6% less than their closest non-GM relatives and 11% less than
high-yielding non-GM varieties [2]. The yield penalty was attributed to the
gene insertion process.
Similar yield drags have been reported since
1997
In summary, yield losses, not yield gains, are
more commonly associated with transgenic crops compared to best available
conventionally-bred cultivars and hybrids [8].
Yield drag in soya is associated with
problems in root development, nodulation and nitrogen fixation, particularly in
drought or infertile conditions, as the bacterial symbiont responsible for
nitrogen fixation is sensitive to both Roundup and drought [9]. Furthermore,
there is a metabolic cost to expressing herbicide-resistance or the
Bt-endotoxin. For example, levels of proteins responsible for plant defence
responses are depressed following Roundup application. Although these are
eventually restored to normal, pathogens quickly infect the plants in
sub-optimal growing conditions. This forces a diversion of energy to repair
damage, resulting in an essentially irreversible tax on yields.
University of Minnesota economist Vernon W.
Ruttan sums up: "Thus far, biotechnology has not raised the yield
potential of crops" [10].
Yet, an indication of distorted perceptions
was shown through an opinion poll of 800 farmers, most of whom (53%) chose RR
varieties because of perceived higher yields than non-GM varieties. When actual
data from their farms were analysed, exactly the opposite was found [5].
"It is interesting to note... that increasing crop yields was cited by
over half the farmers as the reason for planting GM soya, yet yields were
actually lower".
Bt Resistance and More Pesticides
The other big claim for GM crops is
reductions in pesticide use. In reality, herbicide tolerant and Bt-transgenic
varieties of GM crops are trapping farmers into more reliance on pesticides.
Recently, hundreds of hectares of GM cotton
fields in Bulukumba, South Sulawesi, were destroyed by pests [11].
Officials said that there was "nothing to worry about", and a
spokesperson from Monsanto (the GM Bollgard cotton seed supplier) asserted that
"they are just larva which eat the leaves, but will not disrupt cotton
production". But local farmers complained, pointing out that the supplier
had claimed the cotton variety was resistant to all kinds of pests.
What happens when GM crops fail to deliver
on their promise of pest resistance? Farmers in Australia are now being advised
to spray additional insecticide on Monsanto’s GM Bt cotton, INGARD, "under
conditions of reduced INGARD plant efficacy" [12]. The latest official
guidance [13] makes it clear that Bt cotton is in some circumstances failing to
control the principal target pest it was introduced for, Helicoverpa
armigera.
Even when GM crops express pest resistance,
there is little evidence of reduced pesticide use. This is borne out by data on
transgenic cotton - although to date one fourth of American cotton is produced
with genetically engineered Bt varieties, no significant reductions in the
overall use of insecticides were achieved [14]. In fact, those insecticides
that could be replaced by Bt cotton make up a minor proportion of the
insecticides used.
Similarly, with Bt corn, there is no
independent evidence of a reduction in overall pesticide applications despite
industry claims. Nor is there economic advantage in using Bt corn except in
areas with very high pest infestation. Insecticide use on US Bt corn has in
fact slightly increased, with insecticide targeting European corn borer rising
from about 4% of acres treated in 1995 to about 5% in 2000 [15].
Herbicide use shows a similar picture.
Although the cultivation areas of herbicide-tolerant cotton in the US have
doubled annually over the past few years, herbicide use has shown little
reduction. More revealingly, the sales of total herbicides that can be used
with GM cotton have risen drastically since the introduction of
herbicide-tolerant cotton [14].
While the Roundup Ready soybean system
simplifies weed management, it entails 2-5 times more herbicide use than other
weed management systems [1]. Tolerance to Roundup is emerging in several key
weed species, contributing to increased chemical use. Unbiased field-level
comparisons, drawing on official USDA data, show that RR soybeans require more
herbicides than conventional soybeans, despite claims to the contrary [9, 15].
In 1998, total herbicide use on RR soybeans was 30% greater on average than on
conventional varieties in six US states [9].
Analysis thus shows that RR soybean systems
are ‘…not likely to reduce herbicide use or reliance. Claims otherwise are
based on incomplete information or analytically flawed comparisons that do not
tell the whole story’ [1]. And as for RR corn, USDA data suggest that in 2000,
the average RR corn acre was treated with about 30% more herbicide than the
average non-GM corn acre [15].
Worryingly, research from the University of
Alberta has revealed the rapid creation of multiple herbicide resistant canola
plants in Canada as a result of pollen flow over significant distances [16].
Cross-hybridizations occurred between a glyphosate-resistant variety and either
glufosinate- or imidazolinone-resistant varieties. The evidence pointed to
resistant gene movement via pollen flow from one field to another. Unusually,
this occurred rapidly and multiple times, such that, through random crossing,
certain plants showed triple resistance [17]. One of the triple-resistant
plants was found over 550 m from the pollen sources, greatly exceeding the
100-m buffer mandated for seed producers.
Reduced Profits
The greater expense of GM seeds and
increased herbicide costs can already hit farmers’ pockets. Add to these the
costs of yield drag and technology fees, and it is bad news for profitability.
For example, the added costs for soya producers can be more than 12% of gross
income per acre [1].
The Leopold Center for Sustainable
Agriculture, Iowa State University, interviewed 800 Iowa farmers in 1998 to
determine if growing GM crops was more profitable [5]. Random surveys of 62
continuous cornfields, 315 rotated cornfields, and 365 soya fields concluded
that the difference in profitability was non-significant for both crops. Thus,
the farmers who raised GM crops did not gain any competitive edge.
The first farm-level economic analysis of Bt
corn, in demonstrating less net profit, lower corn prices, and lost corn
exports, questions whether planting GM corn is worth the cost [18]. From
1996-2001, American farmers paid at least $659 million in price premiums to
plant Bt corn, while boosting their harvest by only 276 million bushels - worth
$567 million in economic gain. The bottom line for farmers is a net loss of $92
million - about $1.31 per acre. Furthermore, the US has foregone about 350
million bushels of corn export sales to the European Union since 1996/97
because the EU doesn't want GMOs. This is thus part of a triple negative for
farmers - lost corn exports, lower corn prices and less net profit from Bt
corn.
Furthermore, while transgenic cotton
varieties may make pest control easier, they are not always worth the added
expense when it comes to yield and fibre quality. Research by the University of
Arkansas shows that many conventionals are the highest yielding varieties [19].
Comparing the economics of a Bollgard/Roundup Ready variety with a conventional
variety, "in a year when insect pressure was low… the farmer spent about
$10 an acre less for insect control with the conventional variety than he did
with the more expensive stacked gene variety".
And can we put a price tag on the
environment? Research points to the popularity of GM crops with many North
American farmers because of their "convenience". A University of
Nebraska report shows that farmers are using the technology to needlessly
destroy weeds to get a "weed-free" field [2]. The study demonstrates
not only reduced profits, but also destruction of biodiversity.
Lessons From the South
We would do well to draw on the experiences
of farmers in the South. The viability of non-GM alternatives has been
demonstrated in a review of 208 projects/initiatives from 52 countries, adopted
by 8.98 million farmers on 29 million hectares of land in Asia, Africa, and
Latin America [20]. Using a range of sustainable agriculture technologies -
none of which involved GM – farmers have achieved yield increases of 50-100%
for rainfed agriculture, and 5-10% for irrigated crops.
Low-tech innovations by Southern farmers
have boosted production [21]. For example, in East Africa, corn faces two major
pests – stem borer and Striga, a parasitic plant. By planting a local
weed (napier grass) that the stem borer prefers, pests are lured away from the
corn into a honey trap – the grass produces a sticky substance that kills stem
borer larvae. By planting another weed, Desmodium, between rows of corn,
Striga won’t grow, as it is adverse to Desmodium. Pesticides are
replaced by natural predators, and fertilisers by natural dung, crop wastes and
plants that fix nitrogen from the air.
Further, going organic, entailing a
restriction in the use of synthetic fertilisers and pesticides while excluding
GM technology, could be more beneficial for the economies of developing
countries. The FAO has recently urged poor nations to boost exports of organic
produce to take advantage of booming markets in developed countries [22].
Sustainable agriculture and organic farming
are not a panacea. They however offer alternative approaches to GM technology
that have been demonstrated to provide increased yields and more income, while
remaining environmentally friendly. No myths about this.