Which pesticide formulation consists of a small amount of active ingredient dissolved in an organic solvent?

The choice indicating that the correct formulation is ready-to-use low concentrates (RTU) aligns with the definition that these products contain a small amount of active ingredient mixed with a solvent in a ready-to-apply form. RTUs are designed for convenience, allowing users to apply them without further dilution or mixing.

Emulsifiable concentrates (EC) are actually mixtures of pesticide active ingredients that are dissolved in a solvent, typically oil, but they require dilution with water before application, which distinguishes them from RTUs.

Ultra-low volume (ULV) formulations, on the other hand, consist of very concentrated pesticide with minimal carrier, specifically designed for application with minimal volume. This makes them suitable for aerial spraying or fogging but not classified within the same context as RTUs.

Flowables (F) or liquids (L) usually involve pesticides suspended in a liquid carrier, which might not be a thin solvent solution like that found in RTUs. They often require some mixing before application and have a thicker consistency compared to RTU products.

Thus, ready-to-use low concentrates (RTU) are the most accurate answer, as they embody the formulation described, providing a user-friendly product that requires no additional preparation.