FIELDS of herbicide-resistant sugar beet in eastern England are challenging the idea that genetically modified crops are bad for wildlife.
The experimental fields were alive with weeds and beetles, showing for the first time how GM beet might benefit the environment by supporting more insects than conventional crops without sacrificing yields.
But sceptics say the GM technology simply tempts farmers to 鈥渟terilise鈥� their fields with herbicides, and that European consumers would reject sugar made from such beet.
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A team led by Alan Dewar, Mike May and John Pidgeon at the Broom鈥檚 Barn Research Station in Suffolk grew GM beet varieties that are resistant to either glyphosate or gluphosinate, broad-spectrum herbicides that kill most plants.
The team applied the herbicides four to six weeks after sowing the beet. Crucially, at this stage they only sprayed weeds growing near the emerging seedlings, leaving the 50-centimetre gaps or 鈥済ullies鈥� between the rows of plants unaffected.
Four to six weeks later they applied a second dose of herbicide to weeds in the gullies. Even then, the weeds survived for up to three weeks after being sprayed, providing continued food and refuge for wildlife.
鈥淵ou have 6 to 15 weeks after sowing when you still have the weeds there,鈥� says Pidgeon. The key is to time the spraying to kill the weeds just before they start to compete with the crop, he says.
In fields of conventional beet, farmers use a combination of herbicides, which must be sprayed throughout the growing season, and hoeing to remove weeds. Hoeing damages soil structure, kills earthworms and destroys the nests of birds such as skylarks and lapwings. As a result, fields are usually bereft of wildlife, says Pidgeon. Numbers of skylarks and lapwings have dwindled in Europe as farms have become more mechanised.
Insect traps set by the researchers revealed the GM beet fields to be teeming with thousands of species, including twice as many large carabid beetles as usual and five times as many smaller, staphylinid beetles, which are a favourite daytime food of birds (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2002.2248).
鈥淲e believe [the technique] is relevant worldwide to anything grown in a row, which includes sugar beet, maize, soya and some vegetables,鈥� says Pidgeon.
But sceptics remain unconvinced. Brian Johnson, the biotechnology adviser at the government agency English Nature, says that larger trials would be needed to demonstrate that the measures actually attracted birds back to farms. He also fears that farmers will use the technology to obliterate all the weeds to maximise their yields.
In England, 15 per cent of arable land is used to grow sugar beet. Advocates of the technique say the new GM regime could be the way to bring back wildlife without compromising crop production. Farmers could even be given financial incentives to reintroduce wildlife, Pidgeon suggests.