Development and evaluation of an expert system for diagnosis of tomato diseases

The expert system (ES), designated TomEx-UFV, was built from the organizati on of the specialists knowledge in the diagnosis of tomato disease. The obj ective is to give support to technicians of the extension in the taking of decision, and to aid educational and researchers, as educational tool. The Knowledge was organized in a hierarchical way, by means ora Knowledge tree. The system is of easy use and higly interactive. The diagnosis are accompa nied of the confidence level to be deposited in the answer. The ES, TomEx- UFV for tomato disease diagnosis consisted of 78 questions, 116 rules and 8 7 photographs aiming, at the diagnosis of 37 tomato diseases. Two experts w ere consulted on the development ES phase; 4 experts and 30 users (includin g undergraduate students of agronomy, graduate students in Phytopathology a nd other areas) were consulted during the evaluation phase. The diagnosis a ccuracy index using TomEx-UFV was of 95,8% and that of the users of 35,2%. The students who used the program twice obtained an accuracy index 45% high er than those who did not used it. Thus, the ES showed to be effective as a diagnosis tool, in phytossanitary clinics and phytopathology teaching.