Plant disease can be defined as the sum total of abnormal changes in the physiological processes brought about by any biotic or abiotic factor(s) or by a virus that ultimately threatens the normal growth and reproduction of a plant.
Or, Plant disease is a pathological malfunctioning process of the plant body due to continuous irritation which results in some suffering.
The branch of agriculture or Botanical Science that deals with the cause, etiology, resulting losses and management of plant diseases is called plant pathology or physiopathology.
Classification of Plant Disease:
B. Classification on the basis of Occurrence:
C. Classification on the basis of affected host plants:
Cereal disease, root crop disease, plantation crop disease, forage crop disease, flax disease etc.
D. Classification on the basis of Symptom of the diseases:
Rusts, Smuts, Blight, Wilt, Canker, Mildew etc.