A finely ground formulation that appears as dust but does not dissolve in water is called?

The correct response identifies the finely ground formulation as a wettable powder. Wettable powders are pesticide formulations made from finely ground solids that do not dissolve in water, but can be mixed with it to create a suspension. When water is added, these powders can disperse, creating a mixture that can be applied as a spray; however, they remain particulate and do not dissolve completely.

This formulation type is particularly useful in many agricultural applications because it allows for targeted delivery of active ingredients while maintaining good coverage without the chemicals entering the water column, thus minimizing the impact on non-target species. The ability to suspend in water rather than dissolving enables effective application methods without the risk of contamination from excessive chemical leaching.

In contrast, the other options refer to different types of formulations that either dissolve in water or form emulsions, which do not accurately describe the characteristics of the finely ground formulation mentioned in the question.