Cercospora beticola and Ramularia beticola (leaf spots) as well as Erysiphe betae (powdery mildew) are economically important fungal pathogens on sugar beet leaves in Germany. More and more Cercospora is appearing also in regions with low disease incidence in the past. These “low risk areas” are characterised by cool and/or dry climate and a low share of sugar beet in the crop rotation. Regulation strategies must include regional climatic conditions and site-specific properties. They should aim at the prevention of epidemic development of leaf diseases thus taking into consideration the varying regional infection pressure. Particularly disease forecasting systems must be developed, validated and adapted if necessary. In 2001 a nationwide three–years research project was started (funded by Deutsche Bundesstiftung Umwelt) at the Institut für Zuckerrübenforschung (IfZ) Göttingen in cooperation with Landesanstalt für Pflanzenbau und Pflanzenschutz (LPP) Mainz and including numerous regional partners. The aim of the project is to develop a complex crop protection system within the context of an ecologically sound sugar beet cultivation. The system integrates threshold values, forecasting models, tolerance-levels of sugar beet varieties and fungicide effects according to the criteria of integrated plant protection and optimises the control of the complex of fungal leaf diseases on sugar beets. Disease severity, yield and quality data are obtained from comprehensive, partly polyfactorial field trials and a nationwide monitoring. The poster explains the strategies and structures of the trials and shows selected results from the first year of the project (2001). The crop protection system to be developed shall be integrated into the internet based information system for integrated plant production (ISIP) and in such way put at the farmers`disposal. A considerable reduction of monitoring input and fungicide use is expected after the crop protection system has been introduced into agricultural practice.