From the Ichthypundit

State officials won't spray herbicide on Lake Murray hydrilla

Hydrilla is also called "aquatic kudzu", which gives you some idea. At any rate, the state of Wisconsin isn't going to spray the lake that "supplies water to 40 percent of the Midlands' 537,000 residents". Not because the residents wouldn't like herbicide in their drinking water, but because it would be bad for boats.