QAL Laws & Regulation Practice Exam

The effectiveness of a pesticide can be influenced by which of the following factors?

1. Time of day

2. Temperature, humidity, and exposure to sunlight

3. Type of applicator

4. Color of the pesticide

The correct answer is: Temperature, humidity, and exposure to sunlight

The effectiveness of a pesticide is significantly influenced by environmental factors such as temperature, humidity, and exposure to sunlight. These conditions can affect how the pesticide behaves once applied to the target area. For instance, temperature plays a crucial role in the volatility of certain pesticides; higher temperatures may increase evaporation rates, diminishing the pesticide's effectiveness. Humidity impacts how well a pesticide adheres to surfaces and can affect the biological activity of the chemicals, as some formulations may require moisture to activate effectively. Additionally, exposure to sunlight can lead to the breakdown of sensitive compounds found in certain pesticides, reducing their efficacy due to photodegradation. The other factors mentioned, while they may have some influence, do not carry the same weight as the environmental conditions outlined in the chosen answer. Time of day can affect things like the activity levels of pests or the dew present on surfaces but isn’t as critical in biochemistry as temperature and humidity. The type of applicator may affect the uniformity of application but not the inherent effectiveness of the pesticide itself. The color of the pesticide generally has no bearing on its chemical action or uptake by pests. Thus, environmental factors are key to understanding and maximizing pesticide efficacy.