The study by ERS found a decrease of pesticide and herbicide use when farmers
adopted GM seeds. The decrease in pesticide use was significant.9
This decrease
in herbicide use was also significant (except for the herbicide glysophate, for
which the research revealed a significant increase).10
Other studies have not found a clear connection between the use of GM seeds and
decreased chemical use. For instance, the Iowa State University study discussed
above found that farmers' use of pesticides on GM crops remained "surprisingly
large." Farmers applied pesticides on 18% of non-GM crops and 12% of GM
crops.