Abstract: Disease management has been greatly improved with the new technologies of theInternet. Current information and forecasting systems have not only a positive ecological, but aneconomical one for wine growers as well. Now, it is possible to access the “VitiMeteo”forecasting system free twice a day on the Internet (www.vitimeteo.de). The first “VitiMeteo”module created was “VitiMeteo Plasmopara”. The core of this system is found in the database“Agrometeo”, where all the data from different weather stations are stored. The purpose of“Agrometeo” is to integrate weather data into various other software models. The nextcomponent is “VitiMeteo Growth” which was programmed in cooperation with Hans-ReinerSchultz from the Geisenheim Research Center. More software followed, such as “VitiMeteoInsects”,”VitiMeteo Oidium” and “VitiMeteo Data Graph”. “VitiMeteo Insects” is a programmethat simulates the development of insects and other pests. Walter Kast, from the State Institute forViticulture, Oenology and Fruit Technology Weinsberg, was able to create an algorithm based on“OiDiag-2.2”, which calculates which dates the spraying against powdery mildew (Erysiphenecator) should begin and the time increments between each spray. Weather data are controlledand presented with “VitiMeteo Data Graph”. The VitiMeteo-system is a cooperative projectbetween the State Institute of Viticulture and Enology, Freiburg (Germany), the Swiss ResearchStation ACW, Changins-Wädenswil (Switzerland), and the company GEOsens, Ebringen(Germany). The company Meteoblue (Basel, Switzerland) has provided weather forecasts, whichhave been integrated with our software modules since 2009. This is the first time that an actualforecast of biological processes e.g. incubation period or growth was possible. The requirementsof the “VitiMeteo” forecasting system can be entered quickly, making it an extremely flexiblesystem.