This kind of evidence can't be ignored. Scientists report that the risk of Parkinson’s Disease is significantly greater for individuals with a history of exposure to pesticides. They reached this conclusion after reviewing data from six decades of research.
The results were strongest for exposure to weedkillers and insecticides; not so strong for those pesticides designed to kill disease-causing fungi. And the risk was greatest when exposure was associated with work activities, such as applying pesticides in the field.