Myles and James watch a sequel in the for of Why are they spraying us! The sequel to the critically panned What in The World are they Spraying on us, or WI-TWATS for short. Making a sequel is hard regardless of genre, even crazy conspiracy films. Why are they spraying us, gives us the cold opening, chemtrails exist and here is what they are doing. In a classic return to the tried and tested methods of conspiracy film making, everything is thrown at the audience in the hope that it stick and overwhelms critical thinking.
The League of Nerds 
The chemical that causes Parkinsons disease and is used in organic farming is rotenone.
http://www.nih.gov/news-events/news-releases/nih-study-finds-two-pesticides-associated-parkinsons-disease
However, it is not a herbicide. It is an insecticide and piscicide. Apparently it is still on the list of allowable substances in USDA organic regulations but is banned by the EPA. http://www.motherearthnews.com/organic-gardening/rotenone-organic-zb0z1405zsto.aspx
Funny thing is that organic farms have no organic herbicides. They have to use cultivation which wastes fossil fuel and damages the soil by compacting it. Or they can use slave labour to hand weed.