What does a lower LD50 value indicate about a pesticide?

A lower LD50 value indicates that a pesticide is more toxic. The term LD50, or lethal dose for 50% of the population, is a standard measure used to assess the toxicity of a substance. It represents the dose required to kill half of a test population, typically measured in milligrams of substance per kilogram of body weight (mg/kg).

When the LD50 value is low, it means that a smaller dose of the pesticide is required to achieve lethal effects on 50% of the test subjects, illustrating a higher level of toxicity. Therefore, a lower LD50 signifies that the pesticide poses a greater risk to health, requiring careful handling, application, and adherence to safety guidelines.

In contrast, higher LD50 values indicate that larger amounts of the substance are needed to produce a lethal effect, suggesting it is less toxic. The other options pertain to toxicity levels or safety assessments that do not accurately reflect the significance of the LD50 value.