Which type of pesticide formulation is designed to slowly deliver the active ingredient through breakdown of a coating?

Microencapsulated materials are specifically designed to slowly release the active ingredient over time through the breakdown of a protective coating. This formulation technique is advantageous because it extends the efficacy of the pesticide, allowing for prolonged pest control and minimizing the frequency of application. The microencapsulation process involves encasing the active ingredient in a polymer, which dissolves or breaks down under specific environmental conditions, thus releasing the pesticide in a controlled manner. This characteristic makes microencapsulated formulations particularly effective for both reducing the risk of runoff and minimizing exposure to non-target organisms, as it can limit the immediate availability of the active ingredient.

Granular formulations typically involve solid particles that contain the active substance, but they do not inherently include a mechanism for controlled release that relies on coating breakdown. Fumigants are gaseous pesticides that act through vapor and do not use a slow-release mechanism like microencapsulated materials. Concentrated solvents are typically formulated to deliver the active ingredient rapidly through liquid means, rather than a sustained release. Thus, the defining feature of microencapsulated materials being designed for slow, controlled delivery through coating breakdown makes them the correct answer.