What type of insecticide requires the insect to make contact with a treated area to be effective?

The correct choice is the contact insecticide. This type of insecticide works by requiring the pest to come into direct contact with the treated surface for it to be effective. The active ingredients in contact insecticides damage the insect's exoskeleton or affect the nervous system upon contact, leading to the death of the insect.

In contrast, a stomach insecticide operates differently; it must be ingested by the insect to be effective, targeting the pest's digestive system rather than requiring contact with the treated surface. Systemic insecticides are absorbed by the plants and thus can kill pests that feed on them without direct contact. Micro-encapsulated insecticides are designed to release active ingredients over time but still primarily work by contact. However, their method of action is still based on making contact, differentiating them from the more frequently utilized ingestion-based modes of action in other types.