The researchers studied how the pH of water affects the response of underwater plants to a herbicide called flumioxazin. They tested four different plant species and found that flumioxazin was more effective at controlling plants in neutral pH water compared to high pH water. Coontail was the only plant species that could be controlled at the highest concentration in high pH water. Other plants needed much higher concentrations to be affected. In contrast, plants in neutral pH water were severely damaged by flumioxazin.