1. Environmental impact of GM crops unveiled

Environmental impact of GM crops unveiled

Widespread adoption of genetically modified crops has reduced the use of insecticides, but increased the use of herbicides as weeds become more resistant, according to the largest study of GM crops and pesticide use to date.

By: | New York | Published: September 19, 2016 2:42 PM
Researchers studied annual data from more than 5,000 soybean and 5,000 maize farmers in the US from 1998 to 2011. (Source: Reuters) Researchers studied annual data from more than 5,000 soybean and 5,000 maize farmers in the US from 1998 to 2011. (Source: Reuters)

Widespread adoption of genetically modified crops has reduced the use of insecticides, but increased the use of herbicides as weeds become more resistant, according to the largest study of GM crops and pesticide use to date.

Researchers studied annual data from more than 5,000 soybean and 5,000 maize farmers in the US from 1998 to 2011, far exceeding previous studies that have been limited to one or two years of data.

“We have repeated observations of the same farmers and can see when they adopted genetically modified seeds and how that changed their use of chemicals,” said Federico Ciliberto from University of Virginia in the US.

Despite the decrease in insecticide use, continued growth in herbicide use poses a significant environmental problem as large doses of the chemicals can harm biodiversity and increase water and air pollution, researchers said.

Since 2008, genetically engineered crops have accounted for more than 80 per cent of maize and soybean crops planted in the US, they said.

Maize seeds are modified with two genes: one kills insects that eat the seed and other allows the seed to tolerate glyphosate, a herbicide commonly used in weed killers.

Soybeans are modified with just one glyphosate-resistant gene.

Unsurprisingly, maize farmers who used the insect-resistant seeds used significantly less insecticide – about 11.2 per cent less – than farmers who did not use genetically modified maize.

The maize farmers also used 1.3 per cent less herbicide over the 13-year period.

Soybean crops, on the other hand, saw a significant increase in herbicide use, with adopters of genetically modified crops using 28 per cent more herbicides than non-adopters, researchers said.

Ciliberto, who carried the study alongside Edward D Perry of Kansas State University, David A Hennessy of Michigan State University and GianCarlo Moschini of Iowa State University, attributes this increase to the proliferation of glyphosate-resistant weeds.

“In the beginning, there was a reduction in herbicide use, but over time the use of chemicals increased because farmers were having to add new chemicals as weeds developed a resistance to glyphosate,” Ciliberto said.

Maize farmers, he said, have not yet had to address the same level of resistance, in part because they did not adopt genetically modified crops as quickly as their counterparts in the soy industry.

However, the study did find evidence that both maize and soybean farmers increased herbicide use during the last five years of the study, indicating that weed resistance is a growing problem for both groups.

“Evidence suggests that weeds are becoming more resistant and farmers are having to use additional chemicals, and more of them,” Ciliberto said.

  1. B
    Border Glider
    Sep 19, 2016 at 9:51 am
    Unbelievable article, littered with lies and half truths from beginning to end. The explosive growth of GM maize, wheat, canola, soybeans, cotton etc. across the USA, Argentina and other US client-states, has NOT led to a decrease in use of insecticides. Every single seed of maize planted in the USA is coated with a deadly neonicotinoid insecticide, which is 11,000 times more toxic to bees than was DDT. In all, more than 200 million acres of GM crops are planted in the USA and every seed of wheat, corn, soya etc is coated with the same neurotoxins. These perfuse the entire growing plant from roots to leaves, from flowers to fruit, to pollen and nectar. There is enough poison on a single kernel of planted maize to kill 80,000 bees ( Krupke, Purdue University, 2013). The EPA, in collusion with Bayer, Syngenta and Monsanto, gets around this by declaring that insecticides which are applied as seed coatings, do not qualify as 'pesticide use'. So 95% of all pesticide use in the USA is not 'clified' as pesticide-use. Since 2003 when Clothianidin was introduced on maize and other crops in the USA, at least 20 million bee colonies have died - official USDA figures. Moreover, every single man, woman and child in America has been EATING glyphosate - as well as neonicotinoids - in their bread, cereals, fruit and vegetables for at least 20 years. Of course this has nothing to do with the mive explosion in human cancers, nor in the inexorable rise of autism, ADHD, Aspergers etc - in the children of women who have been eating BRAIN POISONS in their wheaties for the last 20 years.
    Reply

    Go to Top