Texas Pesticide Applicator Practice Exam

Why must spray applications dry onto a surface before rain arrives?

1. To prevent the pesticide from becoming ineffective

2. So the rain won't cause runoff of the pesticide

3. To allow better absorption into the soil

4. To avoid attracting pests

The correct answer is: So the rain won't cause runoff of the pesticide

The primary reason spray applications must dry onto a surface before rain arrives is to prevent the pesticide from washing away due to runoff. When a pesticide is applied, it needs time to adhere to the target surface, whether it's foliage, soil, or other intended areas. If rain occurs before the pesticide has had a chance to dry and bond effectively, it can lead to substantial loss of the pesticide through runoff. This not only diminishes the effectiveness of the application but could also lead to environmental contamination. The other options focus on different aspects that are less relevant in the context of the application timing relative to rain. For instance, while it is true that a dry application may enhance efficacy, the immediate concern is preventing run-off caused by rain. Better absorption into the soil is also a relevant factor, but primarily with soil applications rather than foliar applications that are expected to dry. Finally, attracting pests is not directly impacted by whether the pesticide has dried before rain; it's more about the effectiveness of the application itself.