1Department of Crop Sciences, and 2Web Technology Group, Office of Continuing Education and Public Service, University of Illinois at Urbana-Champaign, USA

Background and objectives
Agriculture includes the production of food, feed, fibre and landscape products, but also encompasses many important issues, such as biodiversity, environmental quality and food safety. People have to make decisions on these issues which directly impact on their daily lives. However, many people lack the information required to make these decisions soundly, a problem known as agricultural illiteracy. The objective of this project is to increase the understanding of agriculture and related issues through the use of a World Wide Web site. This web site is being developed from materials used in a course for undergraduate students entitled 'Plants, Pathogens, and People', which is taught at the University of Illinois. In addition to being used as a teaching aid for this course, the web site will be useful for students in other courses at the University of Illinois, in undergraduate courses at other colleges and universities, and for students in advanced high school courses such as biology, history, integrated science and health.

Materials and methods
As it develops, the web site will be composed of a series of modules, with each module addressing a specific issue or topic using a historically important plant disease as a case study. The first module has been developed and can be viewed, using a web browser, at http://www.extramural.uiuc.edu/PLPA100. This module addresses the concept that a plant disease is the result of interactions among a susceptible host, a virulent pathogen and a favourable environment, the disease triangle. The disease that is used to explore this issue is late blight of potato and the epidemic that it caused in the mid-1800s. The epidemic resulted in the Irish potato famine, which caused the death and forced emigration of millions of people. The module also describes the impact that plant diseases have on people, and how people can affect disease development.

Results and conclusions
The web site is being developed as a cooperative effort of the Department of Crop Sciences and the Web Technology Group at the University of Illinois at Urbana-Champaign. Currently, those visiting the site can enter a lecture hall and obtain information on (i) the history of the Irish potato famine; (ii) how scientists debated and determined the cause of the epidemic; (iii) an introduction to a fungus, Phytophthora infestans; (iv) an introduction to a plant, the potato, (v) the components necessary for disease; and (vi) the importance of potatoes and P. infestans today. In a laboratory the students can conduct experiments to evaluate (i) the effects of temperature and rainfall on disease development; (ii) the effectiveness of using a disease-resistant variety of potato; and (iii) the effectiveness of fungicide applications for control of the disease under various conditions. The students are prompted to record a purpose, a hypothesis, results and conclusions for each of the experiments in a notebook. The contents of this notebook can be printed for the student to keep, and/or e-mailed to the course instructor. The site allows students to explore selected topics in a non-linear, non-time-limited manner. Students can use a virtual slide projector to view drawings and photographs and a virtual microscope to view microscopic images. The site has been evaluated by students on the course, and their suggestions have been used to improve the site. Modules planned for the future include: problems with monoculture, the case of Dutch elm disease; the dangers of natural toxins, the case of ergot and ergotism; and the origins of genetic engineering, the case of crown gall and Agrobacterium tumefaciens.