Which of the following is a common sign that a herbicide is effectively controlling target vegetation?

Visible wilting or discoloration of treated plants is a clear indication that a herbicide is effectively controlling target vegetation. This response from the plants shows that the herbicide is impacting their physiological processes, leading to stress or death in the vegetation it was intended to control.

When herbicides are applied, they often work by targeting specific biochemical pathways in plants, which ultimately manifests as visible symptoms such as browning, wilting, or yellowing of leaves. These physical changes serve as tangible evidence that the herbicide is functioning as intended and disrupting the growth habits of the targeted plants.

While increased aquatic life, rising water levels, and clear water clarity might be desired outcomes of effective aquatic management and herbicide application, they do not provide direct evidence that the herbicide is actively working on the targeted vegetation in the short term. Therefore, they are not reliable indicators of herbicide efficacy.