Bt crops can be safer alternative to pesticides

Date:04-27-2010

A brinjal farmer can be hesitant to consume his own crop. The pest — brinjal fruit borer — can damage up to 70 per cent of his harvest and he resorts to multiple types of pesticide sprays during a single crop cycle in a desperate attempt to control it. Bt brinjal was expected to be a solution to this problem.

Scientists had engineered these plants to produce an insecticidal protein originally made by the soil bacteria Bacillus thuringeinsis (Bt). Bt has been used to control crop pests since 1920s. Bt microbial products have more than 40 years history of safe use especially in organic farming. In the case of Bt brinjal, instead of spraying the protein, the plant was genetically modified (GM) to make the protein. The Bt protein is only toxic to specific insects that include the brinjal fruit borer which is killed upon consuming the brinjal, thereby protecting the plant. Bt thus serves as an effective and environmentally friendly substitute to using deadly chemical pesticides.

Conflicting information
The scepticism over GMs appears to have stemmed from conflicting information from the media, scientific organisations and advocacy groups. Bt poses health risks is a false alarm. Safety studies conducted by independent regulatory committees from many countries including UK, EU, Russia, USA, Canada, Japan and South Africa, found no risk of Bt protein on human health. There is broad scientific consensus that Bt protein is not an allergen, is quickly broken down in the digestive system and shows no toxic effects on animal health. However, it must be noted that no food, whether conventional, organic or GM can be certified as 100 per cent safe.

On the other hand what has been proved clearly are the health hazards of insecticides. WHO records show that 18,000 farmers die from extreme pesticide poisoning every year.

It is argued that Bt crops do not raise productivity and so are giving false hope to farmers. Bt crops never claim to boost yield, but they kill insects that eat the plant thereby reducing crop losses. On an average at least 40 per cent of brinjal produce in India can be lost by insect infestation. Multi-state field trials in India have shown that yield of undamaged fruits from Bt brinjal was double that of non-Bt plants. From a practical perspective this does mean an increase in productivity.

A valid concern among environmentalists is that non-pest insects like the Monarch butterfly could become innocent victims when they feed on Bt crops. However an exhaustive analysis of 42 independent field studies showed that more non-target insects were killed by insecticides than by GM crops.

The effect of GM crops on reducing bio-diversity has been another concern. Ever since humans started practicing agriculture, more than 10,000 years ago, we have always been purposeful in propagating varieties of plants that were the most useful to us leading to a decline in local biodiversity. The green revolution introduced high yielding hybrid crops that unfortunately also led to the loss in diversity of many local cereals and legumes.

This is not a feature unique to GM crops and does happen with conventional plants. Being aware of this, it is important to do all that we can to preserve wild relatives of important plants. For instance national gene banks can serve as great repositories of native species.

By 2006, 250 million acres of land were being cultivated by 10 million farmers in 22 countries. Majority of these farmers are in the US, where up to 80 per cent of the processed food contains ingredients from a GM crop. Last year China approved the bio-safety of Bt rice commercialising the most important food crop in the world. Argentina, Brazil and Canada are the other main producers of GM crops.

The concern of the Indian farmer on the long-term impacts of GM crop technology still remains a valid point. Genetic engineering has opened up ways on altering organisms that was previously thought to be impossible. With great power comes great responsibility and it is wise to proceed with caution.

It is important to exercise caution when it comes to new technologies; however we should not hold GM crops and products to standards not required for food or feed produced by conventional technologies. The UN estimates that in developing countries, food production must be raised by almost 100 per cent between 2007 and 2050. This would put undeniable pressure to get maximum food output from the available arable land. Genetic engineering is not the magic bullet that can take on this challenging task but it is definitely one of the weapons in the arsenal.