New Study Shows
GE Crops Lead to "Superweeds"
(Beyond Pesticides, October 14, 2003) A new study finds evidence that fields of genetically engineered (GE) crops will cross-pollinate with weeds in the same family, creating super-weeds that are resistant to herbicides, according to the London Independent. The British study, which was published in the October 10 edition of the journal Science, addressed the issue because of the severe threat GE cross-pollination poses. Weeds containing an herbicide-resistant gene may result in ineffective increased herbicide use when farmers spray the superweeds repeatedly, unaware that the weeds are herbicide-resistant. Also, weeds that have cross-pollinated with GE crops bred to resist insects may become invasive, spreading beyond their natural habitat and out-competing native plants.
The researchers studied fields of non-GE oilseed rape, along with its wild relative called bargeman's cabbage to see how easily the two cross-bred. They scoured the countryside along 180 miles of riverbank and analyzed satellite images of British countryside, using DNA techniques to assess if any hybridization of the crop and the wildflower occurred. They concluded typically there would be 32,000 hybrids produced annually in wild riverside populations of bargeman's cabbage, and a further 17,000 hybrids growing among a weedier variety of the wildflower which tends to infest farmland. The hybrids made up a relatively small fraction of the total amount of bargeman's cabbage on the riverbanks. However, were an herbicide-resistant gene to be introduced, the extent could be far greater.
Although the oilseed rape studied was not genetically engineered, the results of how easily cross pollination occurs are applicable to GE and non-GE crops alike. Mike Wilkinson of Reading University, who led the study, stated, "Our findings are directly transferable to almost all sorts of genetically modified oilseed rape. The only exceptions will be ones where there is male sterility introduced into the crop." He stated that buffer zones, or areas designed to prevent the drift of GE pollen into the wild, only serve to reduce the amount of cross-pollination that occurs. "This [study] shows that isolation distances will reduce hybrid numbers but not prevent hybridization. It depends on what level of hybridization you deem acceptable but if you want to absolutely prevent hybrids then isolation distances will not do so," Dr Wilkinson said. "Hybridization is more or less inevitable in the UK context," he added.
Public opinion of GE in this part of the world is already quite negative. Localities across the United Kingdom have been acting to restrict fields of GE crops. Beyond Pesticides covered this story in the August 6, 2003 edition of Daily News.
For more information, see Beyond Pesticides' Genetic Engineering Program Page.