A permaculture plot that is designed and maintained in harmony with nature should remain fairly disease-free. With the right sort of companion planting, use of native species suited to the soil and climatic conditions, soil improvement and irrigation techniques, the plants on the site should generally be free from the worst ravages of pest insects, nematodes and vegetative diseases. Indeed, there is a school of thought that if a disease does strike a plant on the permaculture plot then it is an opportunity for learning, to analyze the soil conditions, plant companions or climatic events that may have contributed to the occurrence. One of the ways of learning from plant diseases is to know the signs to look for, so that wherever possible remedial action can be taken to tackle the problem.
Illustrated lessons to introduce the symptoms and signs, pathogen biology, disease cycle, epidemiology, disease management, and scientific, economic and social significance of major plant diseases.