Indiana Pesticide Applicator Core Practice Exam

What does photodegradation refer to?

1. The breakdown of pesticides by sunlight

2. The process of leaching through soil

3. Microbial activity in water

4. The absorption of pesticides into plant roots

The correct answer is: The breakdown of pesticides by sunlight

Photodegradation refers to the breakdown of chemicals, including pesticides, through the action of sunlight. This process involves the absorption of light energy, which can result in chemical reactions that lead to the decomposition of the pesticide molecules. Understanding photodegradation is important for pest management practices, as it can influence the effectiveness and longevity of pesticide applications. For instance, pesticides that undergo rapid photodegradation may have reduced residual activity, affecting their pest control efficacy and environmental impact. The other options describe different phenomena related to pesticides, but they do not accurately define photodegradation. For example, leaching involves the movement of pesticides through soil into groundwater, microbial activity refers to the breakdown of substances by organisms in water bodies, and absorption pertains to how plants take in chemicals through their roots. Each of these processes plays a role in the overall behavior and fate of pesticides in the environment, but they differ from the specific process of photodegradation influenced by sunlight.