What is a primary characteristic of restricted use pesticides?

A primary characteristic of restricted use pesticides is that they are available only through certified applicators. This designation is essential because these pesticides can pose significant risks to human health and the environment if not used properly. Consequently, training and certification are required to ensure that applicators understand the potential hazards and possess the necessary knowledge to use these pesticides safely and effectively.

Unlike general use pesticides, which can be purchased and applied by anyone, restricted use pesticides require a specialized understanding of their properties, application methods, and safety protocols. This limitation is designed to minimize the potential for misuse or accidents that can arise from improper handling by untrained individuals.

In terms of the other options, restricted use pesticides are not freely marketed to the public, they are not always synthetic (as some may be derived from natural substances), and they do not necessarily carry the lowest toxicity ratings; rather, they are labeled as restricted due to their specific risks.