What is the difference between systemic and contact pesticides?

Systemic and contact pesticides serve distinct roles in pest management, primarily based on their method of action. Systemic pesticides are absorbed by plants and translocated throughout their tissues. This allows the pesticide to provide protection from pests that feed on the plant by delivering the active ingredient directly to the site of action, even if the pest does not come into direct contact with the pesticide application.

In contrast, contact pesticides are applied directly to pests or the surfaces they inhabit. They work by creating a toxic effect when pests come into contact with the pesticide. This type of pesticide does not require absorption into the plant and can act quickly on insects or other pests that land on or ingest treated surfaces.

The correct choice identifies this fundamental distinction: systemic pesticides operate internally within the plant, while contact pesticides apply externally to target pests directly. Understanding these differences is crucial for effective pest management strategies, enabling the selection of the appropriate pesticide based on the specific pest problem and the lifecycle of the targeted pest.