How GMOs Cut The Use Of Pesticides — And Perhaps Boosted It Again : The Salt : NPR: 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.Disclosure: I think organic farming is a crock. I also think that common sense always suggested that GMO for foodstuff resistance to herbicides was always doomed for failure, and was mainly about a company making lots of money in the process of eventually making a biological problem worse.
When it comes to weedkillers, though, the picture gets more murky. For one thing, the effect of GMOs has been different in corn than in soybeans. Farmers who switched to glyphosate-tolerant corn also switched herbicides, and used less total herbicide than farmers did on conventional corn — for a while. In the years since 2007, however, glyphosate-tolerant corn got sprayed with more weedkillers, as measured in kilograms per acre, than corn without that GMO trait.
Farmers who are growing genetically modified, glyphosate-tolerant soybeans, meanwhile, have been using more weedkillers than their non-GMO neighbors. In fact, that gap has been widening in recent years.
Edward Perry of Kansas State University, a co-author of the new study, which appears in the journal Science Advances, says farmers may be using more herbicides on glyphosate-tolerant crops in recent years because they have to fight off an increasing number of weeds that have evolved to become resistant to glyphosate.