QAL Laws & Regulation Practice Exam

What is a common effect of applying incompatible pesticides together?

1. Improved efficacy

2. Increase in toxicity

3. Reduced effectiveness

4. Faster decomposition

The correct answer is: Reduced effectiveness

Applying incompatible pesticides together often leads to reduced effectiveness. When two or more pesticides do not blend well chemically or physically, their active ingredients can interfere with each other’s mode of action. This can happen through several mechanisms, such as chemical reactions that neutralize the active components, physical changes that prevent proper application or absorption, or the formation of compounds that may not be effective against the target pest. As a result, the intended pest management goals may not be achieved, leading to poor control of pest populations. Moreover, if the pesticides were expected to work synergistically but do not, the user may not see the expected results, making it appear as if the pesticides are failing in their purpose. This highlights the importance of understanding the compatibility of pesticides before application.