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Classification of plant diseases
 On the basis of extent to which plant
diseases associated with plant
 Localized
 Systemic
 On the basis of natural perpetuation and
mode of infection
 Soil borne
 Air borne
 Seed borne
 On the basis of symptoms
 Rusts
 Smuts
 Rots
 Blight
 Leaf spot
 Canker
 Wilt
 Downy mildews
 Prowdery mildew
 Anthracnose
 On the basis of host plants
 Cereal diseases
 Vegetable diseases
 Fruit diseases
 Forest diseases
 Ornamental diseases
 On the basis of crop
 Diseases of Wheat
 Diseases of maize etc
 On the basis of organ they attack
 Root diseases
 Shoot diseases
 Fruit diseases
 Foliage diseases
On the basis of occurrence and
distribution
 Endemic : when a diseases more or less constantly
prevalent from year to year in a moderate to severe
form in a particular country. E.g., Wart disease of
potato is endemic to Darjeeling
 Epidemic or epiphytotic: A disease occurring
periodically but in a severe form involving major
area of the crop. it may be constantly present in
locality but assume severe form occasionally e.g.
Rust, Late blight, Mildews
 Sporadic: Diseases which occur at very
irregular interval and location in a moderate
to severe form e.g., leaf blights, wilt
 Pandemic: diseases occurring throughout the
continent or sub-continent resulting in mass
mortality e.g., Late blight of potato
Based on pathogen generations
 Simple interest/ Monocyclic diseases
those diseases the increase of which is analogous
of increase in money due to simple interest i.e
those diseases which have only generation in one
cropping season e.g. loose smut of wheat
 Compound interest/ polycyclic diseases
those diseases which have more than one
generation in a cropping season. e.g. late blight of
potato
 Polyetic diseases
these are also polycyclic diseases but they
complete their disease cycle in more than one
year over years e.g. Cedar Apple Rust
 On the basis of cause (Pathogen identity)
 Most useful base of classification as it
indicate
 Cause of the disease i.e. fungus or virus etc
 Possible disease development and host pathogen
interaction
 Management practices to be applied.
 Infectious/ parasitic (Biotic)
 Fungi, bacteria, virus, viroids, phytoplasma, RLBs,
nematodes, higher parasitic plants etc.
 Non infectious (Abiotic)
 nutrional deficiencies e.g. khaira disease of rice due to Zn deficiency,
unfavourable environment e.g. frost injury, physiological wilt etc