Associate Certified Entomologist (ACE) Practice Exam

Which method involves pesticide entering through the integument of insects?

1. Ingestion

2. Respiration

3. Contact

4. Absorption

The correct answer is: Contact

The method by which a pesticide enters through the integument of insects is best described by contact. This approach relies on the active ingredient in the pesticide adhering to the outer covering of the insect, allowing it to penetrate the protective layers of the integument, or exoskeleton. When an insect comes into direct contact with the pesticide, the chemical can disrupt physiological processes, leading to the insect's death or incapacitation. This method is particularly effective for topical applications where the pesticide is applied directly onto surfaces that insects crawl over or come into contact with. Ingestion is a method where pesticides are consumed by insects, typically through contaminated food or other materials, leading to a different mode of action. Respiration involves the inhalation of vaporized pesticides or aerosols; this method affects the internal respiratory systems of insects, not directly through the integument. Absorption does refer to the process of substances moving into the insect's body but is more relevant in the context of chemicals entering through other pathways, not specifically through direct contact with the surface.