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Physiological disorders are plant diseases caused by non-living agents. Other terms for this group of disorders are abiotic diseases or noninfectious diseases.
Physiological disorders are often confused with pathogen-caused diseases but they do not spread from plant to plant as do diseases caused by living organisms. Landscape plants are often exposed to toxic materials, mechanical damage, nutritional stress, homeowner neglect and other stress factors in the urban environment.
This 4-color extension publication highlights the following physiological disorders of landscape plants: sun scald, drought, lightning injury, winter injury, root girdling, iron chlorosis, salt injury, herbicide injury and air pollution.