[Stock & Land, 03 Dec, 2009, page: 38, by Gregor Heard] A report by a US academic has found that rather than reduce pesticide use levels, genetically modified crops actually used higher rates of chemical and have also led to severe problems with glyphosate resistance throughout North America. US scientist Charles Benbrook caused controversy when he visited Australian soils late in 2005 as a guest of anti-GM lobby group Gene Ethics. Some pro-GM lobby groups, such as the Producers Forum, suggested Dr Benbrook overstated his role with the US National Academy of Science (NAS) claims which Dr Benbrook stridently denied.
His latest report claims GM crops have increased overall pesticide use by 144.4 million kilos than would have been used if herbicide-tolerant or Bacillus thuringiensis (BT) GM crops had not been used. His report said herbicide use on GM crops has veered sharply upward in recent years.
Crop years 2007 and 2008 accounted for 46 per cent of the increase in herbicide use over 13 years across the three herbicide-tolerant crops, with the biggest rise 31.4pc from 2007 to 2008. Dr Benbrook acknowledged there was an initial drop in pesticide use when farmers converted to GM crops but said these gains were lost as resistance issues emerged.
However, Monsanto spokesman Honi McNaughton said the report used inaccurate methodology.
"It is inaccurate and misleading in its assessment of biotech herbicide tolerant traits as it fails to acknowledge several key benefits that US farmers and citizens have derived from using the technology," she said.
The Australian example painted a different story to the results claimed by Dr Benbrook, she said.
"Australian cotton growers have reduced the use of pesticide spraying by some 85 pc since the introduction of GM cotton in 1996." And she said there were further environmental benefits to consider from the adaptation of GM technology.
Biotechnology has allowed farmers to adopt no and reduced tillage systems which utilise herbicidal weed control rather than ploughing," Ms McNaughton said. "This means increased soil health and water retention, reduced runoff, fuel conservation and reduced greenhouse emissions leading to more efficient carbon storage in the soil."
Gene Ethics director Bob Phelps said the report was another case of promises by the big biotechnology companies not being right.
"We were told GM was going to solve all the world’s food security issues, and that isn’t right, and we were told that it would be good for the environment, now we can see this isn’t right either," Mr Phelps said.
He claimed GM crops, especially herbicide-resistant crops, were wreaking havoc through weed resistance problems.
"Weeds like pig weed are a problem right through North America, and you can see the chemical burden is greater than before as growers have to go to greater lengths to control these problem species." He said it was common However, his findings were that the advent of glyphosate resistance was a big problem.
"Excessive reliance on glyphosate has spawned a growing epidemic of glyphosate- resistant weeds, just as overuse of antibiotics can trigger the proliferation of antibioticresistant bacteria," he said.
"Glyphosate resistant weeds were practically unknown before the introduction of Roundup Ready crops in 1996." "Today, nine or more GR sense that products developed by chemical companies would not use less pesticide.
"Their business is selling chemicals and if these chemicals are so dire that we need to trumpet lower usage, then shouldn’t we just ban them altogether?"
Dr Benbrook’s report was not all negative. He found that Bt corn and cotton delivered consistent reductions in insecticide use, with total reductions of 29.1 million kilograms over the 13 years. weeds collectively infest millions of acres of US cropland,"Dr Benbrook claimed.
However, Ms McNaughton said weed resistance was not a monster created by the use of GM crops.
"The fact is, whenever farmers use the same control methods repeatedly, there is a chance that some pests will develop resistance to a specific crop protection product," she said.