Contents: I. Scheunert, Neuherberg, FRG: Physical and Physico-Chemical Processes Governing the Residue Behavior of Pesticides in Terrestrial Ecosystems.- Transformation and Degradation of Pesticides in Soil.- Fate of Pesticides in Plants and in Soil Fauna.- H. Parlar, Kassel, FRG: Mechanism for the Behavior of Pesticides on Surfaces.