MDARD Michigan Core Pesticide Applicator Practice Exam

What does a lower LD50 value indicate about a pesticide's toxicity?

1. It is less toxic

2. It is more toxic

3. It is non-toxic

4. It is obsolete

The correct answer is: It is more toxic

The LD50 value, which stands for lethal dose for 50% of the test population, is a critical measure of a pesticide's toxicity. A lower LD50 value indicates that a smaller amount of the pesticide is needed to produce a lethal effect in half of a tested population, meaning the pesticide has a higher level of toxicity. This measurement is commonly used to assess the safety of various substances, including pesticides, where the goal is to understand the potential risks associated with their use. Therefore, when evaluating pesticides, those with lower LD50 values are considered more toxic compared to those with higher LD50 values, as they pose a greater risk to non-target organisms, including humans and beneficial species. High toxicity can have significant implications for handling, application, and environmental impact, necessitating cautious use and adherence to safety guidelines to minimize harmful effects.