What is the main effect of humidity on herbicide application?

Low humidity can indeed impact herbicide application by causing premature drying of droplets. When the humidity levels are low, the moisture in the droplets can evaporate much faster than desired, which can lead to uneven application and reduced effectiveness of the herbicide. This is because the herbicide may not have enough time to properly adhere to the target plant or penetrate the plant material effectively before the droplets dry. Proper application often requires a careful balance of environmental factors, including humidity, to ensure optimal effectiveness of the herbicide. High humidity, on the other hand, generally slows down evaporation, allowing herbicides more time to act, but it is the low humidity scenario that can be particularly detrimental by leading to insufficient coverage and possibly reducing the overall efficacy of the herbicide.