The increasing complexity of horticultural problems forces scientists in horticulture to modify their conception of the systems they work with and the methods for analysing and solving problems and designing solutions. Although cases do exist where only one small element represents a major bottleneck, modern horticultural production systems are, in general, characterised by intricate relationships and a high level of development, where improvements are only realised by sophisticated and well balanced modifications of the system and subsequent fine-tuning of the adapted production system. In addition problems encountered nowadays in the horticultural industry often result from interactions with the outside world : the role of the market, the consumers and environmental issues can no longer be ignored.
In this constellation methods to analyse and handle complex systems are indispensable. A system approach, based on models of various degrees of complexity and at various levels of integration, has proved its potential to deal with this kind of problems. Models of greenhouses, crops, pests, as well as tools based on such models enable scientists of different disciplines to join forces and to re-use knowledge generated within another context, for another crop, or another situation.