Which type of pesticide formulation may contain up to 100% active ingredient?

The correct choice relates to Ultra Low Volume (ULV) formulations, which are designed to deliver very high concentrations of active ingredients compared to other pesticide formulations. These formulations minimize the volume of the product that is applied while maximizing the concentration of the active ingredient, allowing for more efficient pest control with lower overall amounts of material used. Since ULV formulations can be composed of nearly pure active ingredient, it is possible for them to contain up to 100% active ingredient, depending on the specific formulation and context of use.

In contrast, formulations like Ready-to-Use typically include a significant amount of inert ingredients alongside the active components, reducing the concentration of the active ingredient significantly. Suspension formulations, which hold solid particles of active ingredients in a liquid, and Emulsifiable Concentrates, which mix water and oil phases, also tend to contain lower percentages of active ingredients due to the nature of their formulations, as they are designed for ease of application and stability rather than maximum concentration. This makes ULV formulations unique among pesticide options.