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

The factor that does not contribute to the rate of herbicide application is the color of foliage. While the concentration of the active ingredient in the herbicide, environmental conditions such as temperature and humidity, and the size and health of the target plants all play crucial roles in determining how much herbicide is needed and how effectively it will be absorbed, the color of the foliage itself does not have a significant impact on the application rate.

Foliage color might affect visual assessments of plant health or stress but does not directly correlate with the physiological processes that influence herbicide uptake and absorption. Understanding the key elements that affect herbicide application is vital for effective pest management, ensuring both efficacy and safety in aquatic environments.