Which factor does NOT contribute to the rate of herbicide application?

The rate of herbicide application is influenced by several important factors, and understanding these factors helps in determining how effectively a herbicide can control aquatic pests.

The concentration of active ingredient is critical because it directly affects the efficacy of the herbicide; higher concentrations may result in more effective pest control but could also lead to increased risks of non-target damage and regulatory issues. Environmental conditions, such as temperature, humidity, and wind, play a vital role as they can impact the herbicide's absorption and degradation, affecting both efficacy and safety. Additionally, the size and health of the target plant are crucial since larger or healthier plants may require different application rates to achieve effective control.

In contrast, the color of foliage does not have a significant impact on the rate of herbicide application. While color may influence how plants absorb light and potentially their overall health, it does not directly correlate to the effectiveness of the herbicide application in terms of dosage or rate required. Thus, it is not a contributing factor in determining how much herbicide to apply.