CALIFORNIA, Aug 16: Glyphosate is the active ingredient in Roundup, a weedkiller manufactured by Monsanto. Roundup is the most popular weedkiller in the US, and last week a court in California ordered the company to pay $39 million in compensation and $250 million in punitive damages to a school groundskeeper who developed non-Hodgkin’s lymphoma after years of using Roundup at work.