London (12th June 2006) – There has been ongoing concern that the continued use of Bt-resistant cotton and maize would produce resistant strains of insects meaning that control would be lost (although those same insects would continue to be susceptible to other insecticides).

To minimise that possibility, management procedures were devised:interspersed among areas of Bt crops, local plantations would be sown with non-resistant varieties, patches of specified size called “refugia” . The idea was that even if resistant insects should occasionally arise from the Bt crops, they would be most likely to interbreed with the overwhelming numbers of their sensitive brothers and sisters from the refugia so the resistance trait would not spread at all, or do so only very slowly.

Sceptics and anti-GM agitators maintained that such measures would not be effective: resistant insects would rapidly develop immunity to the Bt sprays already in use by some farmers.

The fact of the matter is that, even ten years on, those resistant insects have been very slow in coming and now we can see the reason why. In the US, more than 90% of growers are aware of and effectively comply with the Insect Resistance Management (IRM) requirements as mandated by the US Environmental Protection Agency.

In 2005, a telephone poll showed that 92% of U.S. Bt corn growers met or exceeded the minimum recommended refuge size, up from 91% in 2004 and 86% in 2003. On-farm visits found more than 94% of producers met refuge requirements. Those with small and large acreage are meeting the requirements at similar levels.

Once again – as so often – the gloomy prognostication of those people and groups implacably opposed to agricultural biotechnology have been proved wrong.

Source:

More than 90% of corn growers adhering to IRM requirements. Agriculture Online (April 28th, 2006) (http://www.agriculture.com/ag/story.jhtml?storyid=/templatedata/ag/story/data/1146229657332.xml

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