What type of pesticide formulation looks like dust but does not dissolve in water?

The correct choice describes a pesticide formulation that appears as dust and is characterized by its insolubility in water. This aligns with the formulation known as a wettable powder (WP or W). Wettable powders are finely ground solid particles that can be suspended in water for application. However, they do not dissolve in water like soluble powders do. Instead, they remain as a suspension, which is why they may look like dust.

The ability to form a suspension allows for effective distribution across surfaces when mixed with water, enabling the active ingredient to interact with pests effectively while remaining in a solid form. This formulation can often provide a more controlled release of the pesticide.

In contrast, the other options refer to different types of formulations with distinct characteristics. Granules, for instance, are larger particles designed for applications in soil or vegetation as they are meant to dissolve slowly over time, releasing the pesticide into the environment. Microencapsulated formulations are usually designed for controlled-release applications and can include water-soluble components, while water-dispersible granules require water for activation and are formulated to dissolve in water rather than remaining undissolved. Thus, wettable powders stand out as the formulation that meets the criteria of looking like dust and being insoluble in water