Foliar interception and retention values after pesticide application. A proposal for standardized values for environmental risk assessment

In performing risk assessments for plant protection products by applicants or regulators in relation to the registration of the products, an important aspect to take into account is the foliar interception and retention of th e active substance of the product on the plant. An overview is given of the approaches to this item in several parts of the world. The relevant circum stances and influencing variables, such as growth phase, planting density, and some physicochemical characteristics (e.g., vapor pressure and Henry's coefficient) are dealt with. Finally, a proposal is presented for how to ta ke into account the phenomenon of foliar interception and retention in the initial phase, first tier, of the risk assessment process.