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Understanding the Relationship between Host, Pathogen, and Environment


A basic tenet of pathology – whether dealing with plants, animals or people – is that for disease to occur, there must be the right mix of environmental conditions, a host that is susceptible and a pathogen capable of inciting disease. If any one of these is not present, disease will not occur. The disease triangle is a simple model that plant pathologists use to represent the key factors that lead to the development of disease and in an indirect way, clues about how to manage a particular disease.

The host must be susceptible to attack by the pathogen. The pathogen must be able to attack the host. The environment must favor the development of the pathogen. Types of Pathogens are viruses, bacteria, phytoplasmas, fungi, fungal-like organisms, nematodes, parasitic higher plant. Disease is most severe when the environment favors pathogen growth and development over the host.

*click on the image for more information regarding the disease triangle

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