When applying dyes in water for pest control, which rule should be followed?

When applying dyes in water for pest control, it's crucial to ensure that the concentration of the dye remains effective for its purpose. Applying dyes where water will dilute their concentration could lead to ineffective pest control results, as the dye may not achieve the required visibility or toxicity levels needed to manage the pests effectively. Maintaining the proper concentration of the dye is essential for ensuring that it can adequately target and help control aquatic pests.

The other options, while they may suggest specific conditions under which dyes might be applied, do not effectively address the core principle of maintaining effective concentrations. For instance, limiting application to certain seasons, times of day, or specific water clarity does not guarantee the effectiveness that comes from ensuring concentrated application. Thus, the emphasis on avoiding dilution by ensuring the dye is used in appropriately controlled environments is the most critical rule to follow.