Texas Pesticide Applicator Practice Exam

Acute oral toxicity and acute dermal toxicity are measured as LD50. The higher the LD50, the:

1. More toxic the pesticide

2. Less toxic the pesticide

3. More hazardous the application

4. Less hazardous the application

The correct answer is: Less toxic the pesticide

The concept of LD50, or lethal dose for 50% of the test population, is a critical measure in assessing the toxicity of substances, including pesticides. A higher LD50 value indicates that a larger dose of the pesticide is required to cause lethality in 50% of the population tested, which translates to a lower level of toxicity. Therefore, pesticides with higher LD50 values pose less toxicity to organisms. In practical terms, this means that if a pesticide has a high LD50, it is considered to be less hazardous since it is less likely to cause harm at typical exposure levels. This understanding is pivotal for applicators and users in making informed decisions about the use of various pesticides and understanding their safety profiles in relation to human health and environmental impacts.