In what scenarios is the use of systemic insecticides particularly effective?

Systemic insecticides are particularly effective when used against root-eating pests. These types of insecticides are absorbed by the plant and transported throughout its system, including its roots, stems, and leaves. Consequently, they become part of the plant's tissue, making it toxic to insects that consume different parts of the plant, including those that feed on the roots.

Root-eating pests, such as certain types of grubs or larval forms of beetles, can be effectively targeted because they will ingest the treated plant materials, leading to their control. This method is advantageous because it allows for effective treatment even when the pests are not in direct contact with the insecticide or when other application methods, such as surface sprays, may be ineffective.

The use of systemic insecticides is not as effective for surface pests since those insects feed on the outer parts of the plant and may not encounter the insecticide effectively. Scenarios involving high pest resistance would require different management strategies, as systemic insecticides may not overcome resistance in certain pest populations. Additionally, pests that are exposed directly to an insecticide usually involve contact insecticides, which would not utilize the systemic properties effectively.