Wayland Town Crier 3/19/09: Herbicide proposal for Lake Cochituate draws ire, support. State officials proposing to use a herbicide to kill weeds in Lake Cochituate received a cool reception from most people at last night’s Conservation Commission meeting. Officials from the Department of Conservation and Resources, which oversees the lake, propose using the herbicide diquat to treat about five acres around the swimming beach and boat ramp near Rte. 30.