What characteristic describes contact herbicides?

Contact herbicides are designed to affect only the plant tissue that they physically come into contact with. This means that when such a herbicide is applied, it will cause damage or death to the portions of the plant it directly touches, but it does not move systemically throughout the plant to kill the entire root system or other uncontacted parts. This characteristic is important in understanding their usage, as contact herbicides are often employed for specific applications such as weed management in non-crop areas or for targeting specific parts of a weed without affecting the surrounding environment.

In contrast, while some herbicides are designed to kill entire plants by absorbing into the roots and moving throughout the plant system, contact herbicides are much more localized in their impact. Thus, knowing that they only affect the plant where they make contact is crucial for effective application and management strategies when using these products.