What distinguishes contact pesticides from systemic pesticides?

Contact pesticides are formulated to affect pests through direct contact rather than being absorbed and transported within the plant or organism. When these pesticides are applied, they work immediately upon contact with the targeted pests, such as insects or fungi. This results in a rapid response, as the pesticide disrupts the biological processes of the pest almost instantly.

In contrast, systemic pesticides are absorbed by the plant and move within its tissues, affecting pests that ingest parts of the plant, rather than requiring direct contact. This characteristic allows systemic pesticides to offer protection over time, and they are not limited to affecting only those pests that come into immediate contact with the pesticide application.

The other options do not accurately describe the distinctions between contact and systemic pesticides. For example, systemic pesticides can be synthetic as well as organic, they do not exclusively target weeds, and contact pesticides do not necessarily have longer residual effects than systemic ones.