The aim of the programme is to provide farmers with tools and methods which might help in processing tomato crop management in various conditions in order to satisfy all of the following objectives: to produce a given yield of tomatoes, of good market and hygienic quality (given dry matter content, given pH, absence of chemical compounds harmful to human health) for the production of paste; to minimise the use of chemicals for crop protection; to avoid the release of nitrate to the ground; to reduce the production costs. A technical itinerary is defined here as the whole of the reasoning and of the resulting set of decision rules utilized for the application of cultural techniques to obtain a given production (quantity and quality), with controlled effects on the environment and according to social-economic constraints. Based on this definition, a research is performed to construct a model of technical itinerary TImod to reach the previous objectives in processing tomato cropping for paste. TImod is expected to be valid in a wide range of constraint sets. It is constructed from knowledge and from some observations of the state of the environment and of the crop obtainable by farmers At present, the construction of TImod has led to making a set of about hundred rules and subrules and some of them have been formalized in computer softwares. TImod is being tested experimentally during three years from 1997 by 10 scientific partners from 5 countries, operating in 10 locations in the main areas of processing tomato production in the European Union. Observations are made at various stages of the crop to ascertain whether the anticipated behaviour of the environment and the crop has been achieved. In each location another treatment (TIloc) consists in cultivating processing tomato with the same framework of objectives and constraints as TImod, according to a local expert using the current technical knowledge in the given area.