The disease triangle is a widely used, practical conceptual model for teaching basic plant pathology. The concept is often used as a springboard to introduce students to advanced concepts on how diseases develop and the significance of plant diseases in the environment. This article describes development and recommended usage of an interactive learning object entitled "The Disease Triangle." This object provides three levels of instruction on the disease triangle concept, along with appropriate user activities, including concept mapping, and assessments. Research skills instruction to enhance further application of the concept is also recommended.This project was funded in part by the Ohio Board of Regents grant to Ohio State University Technology Enhanced Learning and Research (TELR
