Texas Pesticide Applicator Practice Exam

How does a systemic insecticide function in relation to pests?

1. It only acts on the surface of the plant

2. It kills the pest when it comes into contact

3. It flows inside a treated plant and kills the pest when the pest eats the plant

4. It attracts pests away from crops

The correct answer is: It flows inside a treated plant and kills the pest when the pest eats the plant

A systemic insecticide is specifically designed to be absorbed by the plant and then distributed throughout its tissues, including leaves, stems, and roots. When a pest feeds on any part of the treated plant, it ingests the insecticide, which is lethal to the pest. This method of action is particularly effective against pests that may be difficult to control through surface treatments because they may hide or feed on internal plant tissues. The function of a systemic insecticide contrasts sharply with the other options. A surface-only action implies limited efficacy, as it does not address pests feeding internally. The contact-based action is more reflective of contact insecticides, which require direct contact to be effective. Lastly, attracting pests away from crops does not align with the intended use of systemic insecticides, which focus on pest management through ingestion rather than attraction or repulsion.