What is the difference between systemic and contact pesticides?

What is the difference between systemic and contact pesticides?

• A. Pesticide action is not related to uptake in plant or pest; both work the same
• B. Systemic pesticides are absorbed and translocated within the plant or pest; contact pesticides kill pests on contact and do not require uptake.
• C. Systemic pesticides kill pests on contact and do not require uptake; contact pesticides are absorbed and translocated.
• D. Systemic pesticides are always safer than contact pesticides.

Answer: (B)

Think of how the chemical moves and acts in the system. A systemic pesticide is designed to be taken up by the plant and then move through its tissues. This translocation means the pesticide can reach pests that feed on different parts of the plant, even if those parts weren’t directly treated, and it can protect new growth as the plant grows. A contact pesticide, on the other hand, stays where it’s applied and kills pests only when they touch or feed on treated surfaces. It doesn’t rely on uptake into the plant’s tissues and doesn’t automatically reach distant parts of the plant. So, systemic pesticides provide internal distribution within the plant to reach feeding pests, while contact pesticides require direct contact and do not move through the plant. The idea that systemic pesticides are always safer isn’t generally true, since safety depends on many factors like crop, pest, and application practices.

Think of how the chemical moves and acts in the system. A systemic pesticide is designed to be taken up by the plant and then move through its tissues. This translocation means the pesticide can reach pests that feed on different parts of the plant, even if those parts weren’t directly treated, and it can protect new growth as the plant grows.

A contact pesticide, on the other hand, stays where it’s applied and kills pests only when they touch or feed on treated surfaces. It doesn’t rely on uptake into the plant’s tissues and doesn’t automatically reach distant parts of the plant.

So, systemic pesticides provide internal distribution within the plant to reach feeding pests, while contact pesticides require direct contact and do not move through the plant. The idea that systemic pesticides are always safer isn’t generally true, since safety depends on many factors like crop, pest, and application practices.