Associate Certified Entomologist (ACE) Practice Exam

Which formulation type is most likely to be difficult to apply without proper mixing due to its nature?

1. Soluble powders

2. Wettable powders

3. Emulsifiable concentrates

4. Ready-to-use sprays

The correct answer is: Wettable powders

Wettable powders are formulations that consist of fine particles that need to be mixed with water to create a suspension before application. Due to their particulate nature, if not properly mixed, these powders can clump together or settle at the bottom of the mixing container, leading to uneven distribution of the active ingredient during application. This can ultimately affect the efficacy of the treatment. Therefore, a thorough and proper mixing process is critical to ensure that wettable powders are adequately suspended in the solution before they are applied. In contrast, soluble powders dissolve completely in water, making them less prone to settling issues, and emulsifiable concentrates are generally easier to mix because they form a stable emulsion when combined with water. Ready-to-use sprays are designed for convenience as they require no mixing at all, which eliminates any potential difficulty related to preparation.