Georgia Pesticide Applicators Practice Exam

What is the mode of action for contact pesticides?

1. When ingested by pests

2. When a pest touches the pesticide

3. When a pest is enclosed in a trap

4. When airborne particles settle on pests

The correct answer is: When a pest touches the pesticide

Contact pesticides function through direct interaction with a pest when they touch the pesticide. This immediate contact leads to the pesticide being absorbed through the pest's outer covering, resulting in toxic effects that can ultimately kill the pest or inhibit its ability to feed or reproduce. This mode of action is particularly effective for certain types of pests like insects, which may come into contact with the pesticide through spraying or application on surfaces like plants or soil. The effectiveness of contact pesticides is often reliant on proper application techniques to ensure that the pesticide forms a sufficient barrier or coating for pests to encounter. In contrast, other modes such as ingestion involve pests consuming the pesticide, and being enclosed in a trap does not involve direct contact with the pesticide itself but rather physical containment. Similarly, airborne particles settling on pests may not ensure a lethal dose or effective action compared to direct contact. Thus, the unique mechanism of action for contact pesticides emphasizes the importance of touch in their effectiveness.