Iowa Pesticide Applicator Practice Exam

How do systemic pesticides function once applied?

1. They remain on the surface and do not penetrate

2. They are absorbed and transported within the plant

3. Their action is limited to contact with pests

4. They evaporate quickly and have no lasting effect

The correct answer is: They are absorbed and transported within the plant

Systemic pesticides are designed to be absorbed by plants and then transported throughout their tissues. This unique mode of action allows them to offer protection against pests that feed on various parts of the plant, including leaves, stems, and roots. Once the systemic pesticide enters the plant, it becomes part of the plant's sap, effectively making the entire plant toxic or unappealing to the pests, even if they are feeding on parts that are not directly treated. This contrasts with pesticides that only work on the surface or through direct contact, which may limit their effectiveness. The ability of systemic pesticides to circulate within the plant enhances their longevity and efficacy against pests that may not come into direct contact with the pesticide at the time of application.