WBZTV 6/4/09: Some Concerned About Herbicide In Lake Cochituate. On Lake Cochituate, one Metrowest town is at odds with two others. It’s all over an invasive foreign weed called Milfoil, which has taken over some 50 acres of the lake. The North Pond section of the lake runs through three towns, and while Wayland and Framingham have given the state approval to use chemicals to treat the water, Natick has not.