What is a characteristic of contact herbicides?

Contact herbicides are designed to act quickly on the parts of the plant they come into contact with, and they generally do not penetrate deeply into the plant tissue. Instead, their effectiveness relies on direct exposure to the foliage or stems of the target weeds. Therefore, for contact herbicides to provide effective control, it is crucial that they achieve uniform coverage across the plant's surface. This ensures a sufficient amount of the herbicide interacts with the plant tissues, leading to damage and ultimately killing the weed.

This characteristic distinguishes contact herbicides from systemic herbicides, which are designed to move throughout the plant and often require a different mode of application and target.