Which statement about pesticide toxicity is true?

The statement regarding a pesticide with an oral LD50 of 5 mg/kg being more toxic than one with an LD50 of 250 mg/kg is true because the LD50 value represents the dose of a substance that is lethal to 50% of a test population, typically expressed in milligrams of substance per kilogram of body weight. In this context, a lower LD50 indicates that a smaller amount of the pesticide is required to achieve lethal effects, signifying higher toxicity. Therefore, a pesticide with an LD50 of 5 mg/kg is indeed considered more toxic than one requiring 250 mg/kg to reach the same level of lethality.

This understanding highlights the importance of evaluating LD50 values when assessing the risk associated with different pesticides. In comparison, other statements lack accuracy; for example, the toxicity of pesticides can vary greatly based on formulation, and a higher LD50 does not automatically guarantee safety as it is context-dependent. Additionally, the application method can significantly influence toxicity due to factors like exposure pathways, which further complicates the relationship between toxicity levels and pesticide use.