Pesticide risk is a growing concern that raises environmental, health and economic issues. The regulations and prevention measures that aim to reduce this risk are based on a top-down prevention logic by imposing good practices to be followed by farmers. The analysis of the activity of users of phytopharmaceutical products reveals situations of pesticide risk despite a strong regulatory, technical and social framework of the treatment activity. In this article, we show how pesticide exposure can be documented in the real conditions of use of plant protection products through the development of an extended research community using ergotoxicological tools. The reflections built by wine growers and ergonomists, around activity videos and pesticide measurements, highlight various levels of determinants of pesticide risk situations. Understanding and seeking to act collectively on these determinants supports the agency of the winegrowing professionals and contributes to the development of a constructed prevention.