A new analysis calls for clear policy guidelines to be adopted in developing countries to direct the development of genetically modified crops which could help contribute to greater food security in developing countries.
Synthetic insecticides introduced after the Second World War have substantially improved crop yields by killing pests, such as insects, mites and rodents, that damage crops. Modern synthetic insecticides that are designed to be more target-specific have reduced the environmental impact caused by the older chemicals. However, some developing countries still use older chemicals which need higher application rates. In addition, poor management practices and inadequate health and safety regulations can lead to inappropriate preparation, application, storage and disposal of insecticides.
There is continued debate, particularly in Europe, about the safety of growing genetically engineered or modified (GM) crops. However, this analysis reviews evidence and concludes that the development of GM crops reduces the impact of some of the problems associated with synthetic insecticides, as the crops are modified to produce their own insecticides within the plants.
All commercial insect-resistant GM crops contain various genes from the soil bacterium Bacillus thuringiensis (Bt), which produces toxins that are highly effective at killing a narrow range of target pests. This means that GM insect-resistant crops require fewer insecticide applications compared with similar conventional crops, have fewer impacts on non-target organisms and, in general, produce higher yields.
By 2009, Bt crops were commercially cultivated in 23 countries around the world: 7 developed nations (4 in Europe) and 16 developing countries. Most of the benefit from growing Bt crops has been from increased yields and profitability for farmers compared with non-Bt crops grown in similar circumstances, mainly due to reduced pest damage. As an example, in developing countries the average increase in yield from Bt maize compared with conventional maize was 16 per cent. Local conditions can influence the success of Bt crop yield, and in some cases, such as in India, yields are lower than for conventional crops.
Higher yields do not automatically translate into greater profitability in developing countries. For example, although there may be lower labour costs associated with applying insecticides, this might be offset by greater labour costs in harvesting the crops. However, benefits in terms of increased yields and profitability from Bt crops are generally evident.
Environmental and human health benefits from growing Bt crops are primarily gained from a reduction in the use of insecticides. As an example, the global decrease (21.9 per cent) in the use of insecticides as a result of growing Bt cotton between 1996 and 2008 has been estimated to be over 140 million kg of the active ingredient.
In order to ensure the benefits of Bt crops are sustainable, especially in developing countries, careful risk management strategies are required. These include measures to reduce the risk of target organisms developing tolerance and to avoid an increase in non-target pests due to an overall reduction in the use of insecticides.
Regulatory systems that trial and approve the introduction of Bt crops need to be improved in developing countries. It is important that the necessary local scientific expertise is cultivated, the cost of meeting regulatory compliance is not prohibitively high and that sound policies are in place to guide the evaluation of the potential harm and benefits of growing Bt crops. This includes making the best use of existing risk assessment studies.
Source: Raybould, A & Quemada, H. (2010) Bt crops and food security in developing countries: realised benefits, sustainable use and lowering barriers to adoption. Food Security. 2:247-259.
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