What type of dry/solid pesticide formulation is always applied dry and can easily drift to non-target sites?

The correct answer is dusts. Dust formulations are specifically designed to be applied in a dry form and are characterized by their fine particles, which allows them to be easily dispersed into the air during application. This can lead to drift, where the particles travel away from the intended treatment area, potentially impacting non-target sites or organisms.

Dusts are often used in various settings, including agricultural and household pest control, because they can penetrate areas that liquids might not reach as effectively. Their lightweight nature contributes to their ability to drift more than heavier formulations like granules, which are larger and less prone to being carried by the wind.

Other options are less drifty in nature or do not adhere strictly to being applied dry. For instance, granules are heavier and typically stay in place upon application. Pasters are more viscous and intended for more localized treatment, significantly reducing the likelihood of drift. Wettable powders require mixing with water for application rather than being used dry, thereby eliminating drift in the context of dry application. This specificity of dust formulations regarding dry application and drift makes them the correct focus in this question.