Indiana Pesticide Applicator Core Practice Exam

What process occurs when microorganisms degrade pesticides in the soil?

1. Chemical degradation

2. Photodegradation

3. Microbial degradation

4. Thermal degradation

The correct answer is: Microbial degradation

Microbial degradation is a process in which microorganisms, such as bacteria and fungi, break down organic substances, including pesticides, in the soil. These microorganisms utilize pesticides as a food source or energy, leading to the transformation of these chemicals into less harmful or non-toxic compounds. This process is essential in the environmental management of pesticides, as it helps reduce their persistence in the soil and minimizes potential harmful effects on ecosystems. Microbial degradation can vary in effectiveness depending on factors like temperature, moisture, carbon availability, and the specific characteristics of the pesticide involved. In contrast, other processes such as chemical degradation primarily involve chemical reactions without microbial intervention, photodegradation involves the breakdown of chemicals through light exposure, and thermal degradation refers to the breakdown of materials due to high temperatures. Each of these processes differs fundamentally from microbial degradation, highlighting the unique role that microorganisms play in the soil's ecosystem and pesticide management.