Which statement is true about wettable powders?

Wettable powders are formulations that do not dissolve immediately in water but rather require some form of agitation or stirring to help disperse the particles throughout the liquid. This characteristic is crucial because it ensures that the active ingredients are evenly distributed when mixed with water, allowing for effective application in various pest control or agricultural uses. The need for agitation helps prevent clumping and ensures a uniform spray can be achieved when applied.

The other statements do not accurately describe wettable powders. For instance, they do not dissolve instantly, as settling can occur if left undisturbed; they are not limited to low-pressure spray systems but can be utilized across various equipment types; and they are often compatible with other formulations, depending on their chemical properties. Thus, the requirement for stirring or agitating in water is what defines their proper use and effectiveness.