MDARD Michigan Core Pesticide Applicator Practice Exam

Which pesticide formulation involves solid particles dispersed in a liquid?

1. Emulsion

2. Suspension

3. Solution

4. Granule

The correct answer is: Suspension

The formulation that involves solid particles dispersed in a liquid is known as a suspension. In this type of pesticide formulation, solid active ingredients are finely ground and mixed with a liquid medium, allowing them to be distributed uniformly when agitated. This is particularly useful for ensuring even application of the pesticide, as it can be mixed thoroughly before use. Suspensions are specifically designed to keep the solid particles suspended in the liquid for a period of time, but they may settle out if left undisturbed. This characteristic requires users to shake or stir the suspension before application to guarantee a uniform distribution of the active ingredient, which is essential for effective pest control. In contrast, an emulsion consists of fine droplets of one liquid dispersed in another liquid, typically oil in water or water in oil, rather than solid particles. A solution involves a solute fully dissolving in a solvent, creating a homogenous mixture where no solid phase is present. Granules are solid pesticide formulations that are typically larger and are designed for specific applications, such as to bait or for soil incorporation, rather than being in a liquid dispersion.