Physiological plant disorders are caused by non-pathological conditions such as poor light, adverse weather, water-logging, phytotoxic compounds or a lack of nutrients, and affect the functioning of the plant system. Physiological disorders are distinguished from plant diseases caused by pathogens, such as a virus or fungus. While the symptoms of physiological disorders may appear disease-like, they can usually be prevented by altering environmental conditions. However, once a plant shows symptoms of a physiological disorder, it is likely that that season's growth or yield will be reduced.
Diagnosis of disorders
Diagnosis of the cause of a physiological disorder (or disease) can be difficult, but there are many web-based guides that may assist with this. Examples are: Abiotic plant disorders: Symptoms, signs and solutions; Georgia Corn Diagnostic Guide; Diagnosing Plant Problems (Kentucky); and Diagnosing Plant Problems (Virginia).
Some general tip