How do contact herbicides differ from translocated/systemic herbicides in terms of response time?

Contact herbicides and translocated (or systemic) herbicides indeed exhibit different response times due to their modes of action. Contact herbicides are designed to kill the plant parts they come into direct contact with, resulting in a relatively quick response. This fast action is due to the fact that these herbicides are effective immediately upon application, often within hours, as they damage or destroy the tissues where they are applied.

On the other hand, systemic herbicides are taken up by the plant and then translocated throughout its system. This process is more gradual, as the herbicide needs time to move through the plant's vascular system to reach all of its parts, including roots and leaves. The effects of systemic herbicides can take days or even weeks to manifest, as they work to disrupt growth and functions over time rather than achieving an immediate effect.

This fundamental difference in their mechanisms of action accounts for the different response times observed between these two types of herbicides.