Distinguish systemic from contact pesticides with a practical example.

• A. Systemic pesticides remain on surfaces and kill on contact; contact pesticides are absorbed and translocated within the plant.
• B. Contact pesticides are absorbed and translocated within the plant; systemic pesticides remain on surfaces and kill on contact.
• C. Systemic pesticides are absorbed and translocated within the plant; contact pesticides remain on surfaces and kill on contact.
• D. Both types are absorbed and translocated identically.

Answer: (C)

Systemic pesticides are absorbed by the plant and moved through its vascular system, so pests that feed on the plant’s tissues ingest the toxin even if the spray or bait wasn’t directly on the pest. A practical example is a soil-applied systemic insecticide taken up by the roots and transported to new leaves; aphids feeding on those sap-filled tissues encounter the toxin and are killed. This internal movement means protection can reach parts of the plant not directly sprayed.

In contrast, contact pesticides stay on the plant’s surface (or on the pest) and must touch or be eaten by the pest at the time of application. They don’t move inside the plant to protect new growth unless re-applied. An example is an insecticidal soap or contact spray that kills pests only through direct contact.

So, the best answer reflects that systemic pesticides are absorbed and translocated within the plant, while contact pesticides remain on surfaces and kill on contact.