In the context of pesticide toxicity, what does a lower LD50 value signify?

A lower LD50 value signifies higher toxicity because the LD50 (lethal dose for 50% of the population) reflects the dose of a pesticide required to kill half of a test population, typically adjusted for body weight. When the LD50 value is low, it indicates that only a small amount of the substance is necessary to achieve lethal effects, meaning that the pesticide is more toxic.

In practical terms, this means that substances with low LD50 values pose a greater risk to organisms, including humans, due to their potency at lower exposure levels. Understanding LD50 is crucial for pesticide regulation, safety measures, and risk assessment, as it provides a clear metric for comparing the toxicity of various chemicals and determining safe application practices.