Which liquid pesticide formulation consists of a small amount of active ingredient (often 1 percent or less per unit volume) dissolved in an organic solvent?

The correct choice is the ready-to-use low-concentrate solutions (RTU). These formulations are designed for convenience and safety, typically containing a very low percent of active ingredients—often around 1 percent or less—dissolved in an organic solvent. This allows users to apply pesticides without the need for further dilution, making them user-friendly for non-professional users and more accessible for quick applications in light infestations.

In contrast, other formulations do not align with this definition. Ultra-low volume (ULV) pesticides are designed for applications where very small volumes are used for high efficacy, often involving higher concentrations of active ingredients. Flowables (F) or liquids (L) generally contain larger amounts of active ingredients and are used to create suspensions rather than a simple solution. Emulsifiable concentrates (EC) consist of active ingredients mixed in a solvent and are often used to create emulsions, also usually containing a higher concentration of active ingredients, rather than a low-concentrate solution. Thus, the properties and uses of RTU solutions make them distinctive in the context of low-concentration liquid pesticide formulations.