Recent studies point to troubling effects of genetically engineered insect-resistant crops on beneficial insects, the director general of the International Centre of Insect Physiology and Ecology, Dr Hans Herren, has said. These studies highlight the need for testing of impact on non- target species before genetically- engineered crops are approved for wide-scale use. He was addressing journalists during a seminar on environmental policy at the African Centre for Technology Studies at Gigiri, Nairobi.

Scientists from the Swiss Federal Research Station for Agroecology and Agriculture in Zurich, Switzerland, conducted two studies that looked at the effects of Bt (Bacillus thuringiensis) toxin on green insects. In nature, these insects feed on the (major) pest targeted by Bt corn, the European corn borer. Lacewings, which are known for their appetite for aphids and other insects, play an important role in maintaining the equilibrium of insect populations. They are also important for pest control strategies. In one study recently published in the Journal of Environmental Entomology, researchers found that the mortality rate of lacewing larvae increased significantly after eating Bt toxin similar to that found in genetically-engineered corn. On the indirect impact of GM crops on beneficial insects, researchers compared the mortality and developmental rate of two groups of lacewings - one that had been fed European corn borers reared on engineered Bt corn, and another reared on corn borers fed on non-Bt corn (the control group). The experiments revealed that green lacewings fed on corn borers that had eaten Bt corn had a higher death rate and delayed development compared to the control group. More than 60 per cent of the lacewings fed on Bt corn-reared corn borers died compared with fewer than 40 per cent of the control group. The researchers suggest that the higher mortality is directly associated with Bt-related factors. Among surviving lacewings, those feeding on Bt-corn-reared borers required an average of three more days to reach adulthood than the control group.

In the third study, Scottish Crop Research Institute scientists found that ladybird beetles fed on aphids reared on transgenic potatoes experienced reproductive problems and failed to live as long as lady birds fed on aphids from ordinary potatoes. The researchers found that egg production of female ladybirds fed on transgenic potato-reared aphids was reduced by more than one third, compared with the control group. Nearly three times as many fertilised eggs from engineered-potato-reared aphids died before hatching, compared with fertilised eggs from the control group. In addition, female ladybirds fed on aphids from transgenic plants lived only half as long as females from the control group.

Dr Herren broadly talked on whether we need genetically- engineered crops to feed Africa. This question is at the centre of several major controversies, ranging from intellectual property rights to biodiversity conservation via social and economic considerations. The major question really is what choices science, industry and governments are proposing to the farmers and the consumers.

In a paper entitled Potentials and threats of Genetic Engineering Technology: Quest for an African Strategy at the Dawn of a New Millennium, Dr Herren said despite chronic food problems in Africa, genetic engineering will not offer any solutions to the complex situation in Africa. He said the spectre of a new fiasco lies very near, as African farmers are likely to be misled to move towards biotech which seeks endorsement of solutions to the developing world's food security problem from genetically engineered food crops. Too many hopes and expectations are being entrusted in these technologies to the detriment of more conventional and proven technologies and approaches that have been very successful. While acknowledging that in some instances these technologies may be useful in increasing the quality of food crops, this aspect only has relevance once abundance has been achieved.

Africa needs a home-grown food security research, capacity and institution-building and implementation strategy that is tuned to its economic and social constraints and is in harmony with its diverse environment," said Dr Herren. Despite the enormous investments to date, the progress in developing new crop varieties and livestock breeds and clones, although quite dramatic in scientific terms, has so far lagged behind expectations and promises, particularly in the genetic engineering sector. When considering the many different products arising from biotechnology and genetic engineering, of particular concern are the newly-developed transgenic varieties of common crops.

The agro-industry obviously has in mind its shareholders, who are more interested in the short-term profitability than in the long- term sustainability of any given production system, even for their own food. Thus, if industry can sell a package that has to be bought over and over again, perhaps at an increasing number and cost per application, the better. This trend can be illustrated by the packaging of herbicide-resistant seeds and complementary herbicide. The latest development in this profit to-use treadmill direction is the 'terminator' gene, which will ensure that a given transgenic crop variety will not germinate in the second season, forcing the farmer to buy new seeds every season. On the one hand, this may assure better-quality seeds, but on the other, what does it do for the sustainability of the African farming system, and for the economics of the small farm and the ever poorer rural and urban populations?

Given the wide variety of agro-ecologies found in the tropics, Africa in particular, there is therefore a need for a broad range of ecologically suited varieties. Sufficient evidence already exists of past crop failures due to genetic uniformity to be worried: five in the last 25 years. It seems that here also, there is a problem in learning from past experience," said Dr Herren. The use of new, high yielding and possibly pest-and disease-resistant modified crops will bring with it the need to invest in extra inputs, as shown during the Green Revolution in Asia. With or without the transgenic crops, there will be a need for extra inputs, but the seed costs alone for high-yielding varieties - and more so for the transformed ones - is likely to be above the means of most African farmers.

As it is, most Third World farmers can scarcely afford the regular hybrid or improved open- pollinated seeds. It is well documented that yield can be increased two- or three-fold in most of sub-Saharan Africa and other tropical areas through increased use of fertilisers both organic and inorganic), weed control and utilisation of already developed and available varieties. One may say that we need to prime the pump, and get the farmers out of the vicious circle. Yes, that could have been done 25 years ago, if it were feasible. The problem is the lack of policies and will, at government level, to put agriculture at the top of the agenda."

According to him, what Africa needs now is not transgenic crops. It is a progressive policy environment, in which farmers are given the necessary credit facilities, a tool box with manageable solutions to their agronomic problems and access to markets. They must be given the chance to buy, through micro-credit schemes, the right inputs at reasonable prices, and on time. Without micro-credit, no technology, either traditional or biotech- based, can be introduced," Dr Herren adds. Dr Herren said Africa is the origin of several major food crops. The wild relatives of these crops are now in danger of becoming bio-contaminated with stray genes from their genetically- modified relatives. This scenario is real, and represents the most serious issue facing the deployment of transgenic crops. In order to assess the potential threat, there is a need to urgently undertake research on gene flow of sorghum, cowpeas, coffee, etc. This research could yield data to make informed decisions on the way to proceed, and provide the training ground for specialists to control transgenic crop experiments. The testing of these crops, without proper information on potential unwanted gene flow, is the biggest threat to bio-diversity.

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