Which of the following is NOT a typical characteristic of systemic herbicides?

Systemic herbicides are designed to be absorbed by the plant and then transported throughout its tissues, which allows them to target and kill the entire plant, including the root system. A defining characteristic of systemic herbicides is their ability to move through the plant, which is facilitated by their translocation through the phloem. This movement makes them particularly effective against perennial weeds, which can regenerate from roots or other plant parts.

Killing on contact is a characteristic more aligned with contact herbicides rather than systemic ones. Contact herbicides act primarily where they are applied, killing only the parts of the plant that come into direct contact with the herbicide. Systemic herbicides, conversely, require absorption and translocation to effectively eliminate the entire plant.

Thus, the option that states "kills on contact" does not align with the behavior of systemic herbicides and is not a typical characteristic associated with them. Instead, their efficacy comes from being absorbed into the plant and circulating to affect various growth processes throughout the plant's system.