Which characteristic of triclopyr is correct?

The characteristic of triclopyr as a contact herbicide is accurate because contact herbicides act by physically damaging the plant tissue upon direct application. Triclopyr, which is primarily used to control woody plants and some herbaceous weeds, operates by affecting the foliage it directly touches, leading to reduced growth and eventual plant death.

In contrast, some herbicides work systemically, entering the plant through the roots or leaves and moving throughout the plant's system. Triclopyr is specifically designed to be effective where it is directly applied, which aligns it with the definition of a contact herbicide. The other characteristics listed, such as being non-selective or an enzyme inhibitor, do not accurately apply to triclopyr; it is selective for certain plant types rather than affecting all plants indiscriminately. Additionally, it does not function primarily as a pre-emergence herbicide, which targets seeds before they germinate.