A Laboratory Miniproject in Plant Disease Diagnosis

An exercise in disease diagnosis by proving the pathogenicity of a microorganism following Koch's Postulates is an important part of most plant pathology and some microbiology laboratory courses. Such an exercise fits in general biology teaching as well; it would be a useful part of courses in botany, microbiology and mycology because: (1) the principles for proving pathogenicity are common to pathogens of animals, humans and plants; (2) it provides practice in the methods used to study fungal and bacterial pathogens; and (3) it provides an introduction to microorganisms that cause economically important plant diseases.