Do GM crop plants contribute to reduce pesticide use?

Yes. Herbicide-tolerant and insect-resistant plants account for more than 95% of the cultivated areas of GM crops and both contribute to pesticide reduction, but also to changes in global crop management that help to reduce potential negative impacts to health and the environment. The effect is most remarkable with plants expressing the natural insecticide protein Bt, conferring resistance to a range of insect pests, specially in maize and cotton. Scientific survey has concluded that Bt expression has contributed to significant reduction in the number of insecticide applications, especially in cotton in every country where it is grown (Phipps RH, and Park, 2002, Fitt et al 2004). This has resulted in direct health benefits for farm workers, as documented in China (Pray et al 2002). Second-generations of GM crops combine variants of the Bt toxins, conferring broader-range insect resistance, while decreasing the risks of selecting resistant insects in the fields. As far as herbicide tolerance is concerned, GM plants promote post-emergence applications, which can be adapted to the actual weed populations during crop growth, hence reduced to a minimum. Moreover the broad-range herbicides used, glyphosate and glufosinate, are relatively environmentally friendly (low toxicity and short persistence) and contribute to decrease the amounts of more toxic chemicals accumulating in the environment. Further environmental benefit results from the reduction of tillage (‘conservation tillage’) permitted by the efficient post-emergence weed control, preserving soil erosion and reducing the run off of applied chemicals to water reservoirs.

We recommend the reading of the recent (2006) report of the Swiss Expert Committee for Biosafety for an extensive review of the relevant scientific literature (http://www.art.admin.ch/dms_files/03017_de.pdf),  and the socio-economic and environmental study of the ten-year cultivation of GM crops  (G. Brookes and P. Barfoot, 2006, GM crops: the first ten years – global socio-economic and environmental impacts PG Economics Ltd, UK, Dorchester,  available as ISAAA Brief 36 here).

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