GM crops have failed (6/2/2008)

NOTE: Here's another article as part of our celebration of 10 year's of GM Watch.

As GM Watch editor, Jonathan Matthews, commented in the interview we recently circulated: 'Among the many issues we'd always focused on were the agronomic and economic problems with GM crops, which were a world away from all the hype about these wonder crops that were going to feed the world. Just how flawed this technology was, even at the most practical level, was much less widely appreciated in those early days than it is now, even by opponents of the technology. People had often accepted that there must be some truth in the claims of major benefits for farmers.'

This article (item 1), co-authored with Lim Li Ching, is from 2001. A year later many of the concerns that the article pointed to were borne out by a report from the US Dept of Agriculture - see item 2.


2.Letter Published in 'Farmers Weekly'



'GM crops have higher yields, improved performance, and greatly reduce the use of agrochemicals. Farmers like them because they increase income.'

Lim Li Ching and Jonathan Matthews debunk these myths, documenting the failures of GM crops around the world.


+ Lower yields

+ Bt resistance and more pesticides

+ Reduced profits

+ Lessons from the South

+ References

+ 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 1997, the University of Purdue found that transgenic soya varieties yielded on average 12-20% less than unmodified varieties grown at the same locations [3].

*Research published in 1998 by the University of Arkansas and Cyanamid revealed reduced profit levels and lower yields for GM soya and cotton compared with unmodified varieties [3].

*The University of Wisconsin found GM soya yields from the 1998 harvest lower than non-modified varieties in over 80% of cases in trials across nine US states [4].

*In Iowa, a 1999 survey of reported an average RR-soybean yield reduction of 4% in over 365 fields [5].

*A review of 40 trials of soya varieties in the north central region of the US in 1999 found a mean 4% yield drag in RR soya [6].

*In the UK, reports of crop trials from the National Institute of Agricultural Botany show yields from GM winter oilseed rape and sugar beet 5-8% less than high-yielding conventional varieties [7].

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 it up: 'Thus far, biotechnology has not raised the yield potential of crops' [10].

Yet, an indication of how distorted producer perceptions can be 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 insect

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