What characterizes a systemic pesticide?

A systemic pesticide is characterized by its ability to be absorbed by plants and then translocated throughout their tissues. This means that when a plant takes up the pesticide through its roots or leaves, the chemical spreads within the plant's vascular system, making it effective against pests that feed on various parts of the plant, including leaves, stems, and flowers.

This mode of action allows systemic pesticides to provide longer-lasting protection compared to surface treatments, which only affect pests that come into direct contact with the pesticide on the surface of the plant. Consequently, pests feeding on any part of the plant can be affected, even if they are not present when the pesticide is initially applied.

The other options do not accurately define systemic pesticides. Surface pesticides typically reside in the outer layers of plants, and are not absorbed, while systemic pesticides function through absorption and distribution. Additionally, while some pesticides might be effective specifically in water or target soil pests, systemic pesticides are not limited to these modes of action or targets.