Following my post on organophosphates and ADHD, one of my blog readers asked for more information about derris dust (rotenone) that has been popular with organic gardeners for pest control as rotenone is an organic pesticide made from the roots of a tropical plant. It also has a long history as a piscicide (fish killer).
Rotenone works by shutting down energy production in cells, which makes it a neurotoxin. Research linked it with Parkinson’s Disease, but this was largely discounted as the rats in the research had rotenone injected directly into their brains, which is not a very fair trial.
In 2007, the USEPA published a Re-registration Eligibility Decision (RED) assessing only the risks of contact from its use as a piscicide (i.e. swimming in or drinking treated water). The RED stated that small children and foetuses were more susceptible to the effects of rotenone.
www.environmentalhealthnews.org/ehs/blog/health-ecosystem-effects-of-rotenone-ignored
According to Environmental Health News, researchers have found that rotenone selectively destroys dopamine-producing cells in petri dishes. (The full document on this research must be purchased).
In 2010, another study was published about research in mice that showed a progression of Parkinson’s-like symptoms after mice were fed low doses of rotenone over a period of time. The research found that concentrations in the central nervous system were below detectable limits, yet still induced Parkinson’s Disease pathology.
www.mitochondrial.net/showabstract.php?pmid=19409896
precedings.nature.com/documents/3352/version/3

Australia’s APVMA has reviewed rotenone and decided that it can still be used as a pesticide. However, both Canada and the United States are phasing out the use of rotenone for everything except its use as a fish poison. In Canada, for example, rotenone could not be sold for livestock, gardening, or domestic pet use after the end of 2008, and existing stocks can’t be used after the end of 2012.
www.hc-sc.gc.ca/cps-spc/pubs/pest/_decisions/rev2008-01/index-eng.php

I certainly don’t recommend the use of Derris dust, but gardeners must make their own evaluations of this pesticide.