>In head-to-head comparisons, natural pesticides don't fare any better than synthetic ones. When I compared the organic chemicals copper sulfate and pyrethrum to the top synthetics, chlorpyrifos and chlorothalonil, I found that not only were the organic ones more acutely toxic, studies have found that they are more chronically toxic as well, and have higher negative impacts on non-target species. My results match with other scientific comparisons. In their recommendations to Parliament in 1999, the Committee on European Communities noted that copper sulfate, in particular, was far more dangerous than the synthetic alternative. A review of their findings can be seen in the table on the right (from a recent review paper). Similarly, head to head comparisons have found that organic pesticides aren't better for the environment, either.
https://blogs.scientificamerican.com/science-sushi/pesticide...
"In 2010, a study was published detailing the progression of Parkinson's-like symptoms in mice following chronic intragastric ingestion of low doses of rotenone. The concentrations in the central nervous system were below detectable limits, yet still induced PD pathology.[31]
In 2011, a US National Institutes of Health study showed a link between rotenone use and Parkinson's disease in farm workers."
[Even in America. It can only be used as a "fishkill"]
source: http://npic.orst.edu/NPRO/#
Source(failed petition to remove it): https://www.ams.usda.gov/sites/default/files/media/Rotenone%...