How GMOs Cut The Use Of Pesticides — And Perhaps Boosted It Again

In the ferocious, sprawling brawl over genetically modified crops, one particular question seems like it should have a simple factual answer: Did those crops lead to more use of pesticides, or less?  Sadly, there's no simple answer.  Pesticides include both insecticides and herbicides. Backers of GMOs point to the example of crops containing new genes that fight off insect pests, so farmers don't have to spray insecticides. Biotech critics point to the example of crops that have been altered to tolerate specific weedkillers, like glyphosate, thus encouraging farmers to rely more heavily on those herbicides. This week, scientists at Iowa State made a fresh attempt to answer this question. It's based on the most detailed data ever assembled to examine the issue. Those data came from a private company, which gathered information about the farm practices of 5,000 randomly selected farmers who grew corn and soybeans, the two most widely planted crops in the country. That information allowed detailed comparisons of pesticide use on fields planted with GMO corn and soybeans, compared to non-GMO  fields. Unfortunately, this study probably won't settle the debate. It's that complicated. One of the study's conclusions is straightforward and difficult to dispute. Genetically modified, insect-protected corn has allowed farmers to reduce their use of insecticides to fight the corn rootworm and the European corn borer. There is, however, concern that this effect won't last. Corn rootworms have evolved resistance to one of the genes that has been deployed against them.