Which of the following represents a systemic method of pest control?

The method that represents systemic pest control is applying a pesticide to the soil for root absorption. In this approach, the pesticide is introduced into the soil where it is absorbed by plant roots. Once absorbed, the active ingredients circulate throughout the plant's system, including leaves, stems, and flowers. This means that any pests that feed on the plant will ingest the pesticide, leading to effective control of pest populations.

This method is particularly advantageous because it targets pests that are difficult to reach with topical applications, ensuring more thorough and long-lasting control. Additionally, systemic pesticides can provide protection against a range of pests over time, as they remain active within the plant.

In contrast, the other methods listed, such as spraying a pesticide on leaves, using traps, and manually removing pests, focus on direct physical control rather than the systemic approach that involves absorption and internal distribution throughout the plant.