What characteristic does a high LD50 indicate about a pesticide?

A high LD50 value indicates that a pesticide is less toxic to humans. LD50, or "lethal dose for 50% of the population," measures the amount of a substance required to cause death in 50% of a test group, usually in animals. A higher LD50 means that a larger dose is required to be lethal, suggesting that the pesticide poses a lower risk to human health when compared to substances with a lower LD50 value. Consequently, when evaluating pesticides, a higher LD50 provides reassurance regarding its relative safety for human exposure.

In contrast, a lower LD50 indicates that smaller amounts can be lethal, indicating higher toxicity. While the effectiveness against pests is a relevant characteristic of a pesticide, it does not correlate with human toxicity as directly as the LD50 value does. Similarly, stating that a pesticide has no effect on humans does not align with the LD50 measure, which specifically addresses lethal effects rather than total effects.