Rapid Evolution

A major study into crops genetically modified to repel pests has found that insects are rapidly developing resistance.

They found that bugs had developed resistance that substantially reduced the efficacy of the GM crops in 16 cases as of 2016 – compared to just 3 cases in 2005.

It took just five years for the bugs to be able to shrug off the poisons produced by the GM crops in the 16 areas where bugs developed resistance.

WHAT DID THEY DO?

Researchers looked at 36 cases looking at how insects respond to the GM crops, modified to produce an insect-killing protein called Bt.

Bt is so called because it is derived from a bacterium called bacillus thuringiensis, which is also used as a spray-on insecticide.

In its spray form less likely to spread resistance as it rapidly breaks down in the environment.

They found that bugs had developed ‘resistance that substantially reduced the efficacy of the GM crops in 16 cases as of 2016 – compared to just 3 cases in 2005.

It took just five years for the bugs to be able to shrug off the poisons produced by the GM crops in the 16 areas where bugs developed resistance.

GM crops are illegal to grow in the UK – with exceptions granted for scientific research, but widely grown around the world.

Researchers looked at 36 cases looking at how insects respond to the GM crops, modified to produce an insect-killing protein called Bt.

Bt is so called because it is derived from a bacterium called bacillus thuringiensis, which is also used as a spray-on insecticide.

In its spray form less likely to spread resistance as it rapidly breaks down in the environment.

Bruce Tabashnik and Yves Carriere in the College of Agriculture and Life Sciences analysed the global data on Bt crop use and how insect pests adapt, publishing the results in the journal Nature Biotechnology.

The countries where the GM crops were grown include the US, Brazil, China, Philippines, Spain, Australia and Mexico.

Professor Tabashnik said: ‘When Bt crops were first introduced in 1996, no one knew how quickly the pests would adapt.

‘Now we have a cumulative total of over two billion acres of these crops planted during the past two decades and extensive monitoring data, so we can build a scientific understanding of how fast the pests evolve resistance and why.’

While 16 out of the 36 cases showed resistance, 17 did not. A further three showed ‘early warnings of resistance’.

The researchers said that a way of slowing the development of resistance was by planting ‘refuges’ of non-GM crops close to the GM crops.

This increases the chance that a bug that has genes that resist the killer protein will mate with one that has not – making it less likely the resistant genes will be passed on.

Professor Tabashnik said: ‘Perhaps the most compelling evidence that refuges work comes from the pink bollworm, which evolved resistance rapidly to Bt cotton in India, but not in the U.S.’

He added: ‘These plants have been remarkably useful, and resistance has generally evolved slower than most people expected,’ he said. ‘I see these crops as an increasingly important part of the future of agriculture. The progress made provides motivation to collect more data and to incorporate it in planning future crop deployments.’

Anti-GM crop campaigners said the findings show GM crops are acting as predicted – and spreading resistance to insects.

‘We always expect the pests to adapt. However, if we can delay resistance from a few years to a few decades, that’s a big win’, said Professor Tabashnik.

Liz O’Neill of GM Freeze said: ‘This study confirms a very simple truth: if you try to outwit nature, it’s evolution that wins.

‘The author of the study described measures that have in some cases delayed the development of resistant insects by a few years as “a big win”.

‘That tells us all we need to know about the GM industry’s vision for the future of farming, biodiversity and our natural environment.’

Pat Thomas of Beyond GM said: ‘There have been increasing reports that super bugs are developing resistance to the Bt toxin but this report very starkly shows that technofarming with GMOs just does not work and in fact makes life harder for farmers in the long by run ruining crops and livelihoods.’

Source…


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