2. By Afrasiyab Ahmed

4.  Symptom
Symptoms are the plants response to attack by
a pathogen
 Sign
 signs are structures produced by the
organism
( spore producing structures, mycelium)

5.  Introduction:
 “Any type of injurious abnormality in plants are
called as plants diseases”
 Diseases in plants can be caused by a number of
pathogens and almost all plant species.
 it is difficult to classify plant disease based on
one factor only. So plant diseases can be
classified in many ways based on the various
factors that are involved.

6.  There are four ways to classify plants
diseases
 On the basis of Causal Organisms
 On the basis of the Type of Plants
 On the basis of their Symptoms
 On the basis of their Occurrence

7.  There are 4 types of commonly recognized
organisms
 Virus
 Bacteria
 Fungi
 nematodes

8.  Bacteria nematoades

9.  For example;
 Cereal crop diseases,
 Diseases of fruit crops,
 Diseases of vegetable crops,
 Diseases of ornamental plants

14.  For example;
 Rusts,
 Smuts,
 Powdery Mildews,
 Downy Mildews,
 Leaf blights,
 Vascular wilts,
 Damping off,
 Leaf blights

15. Rust (Rust spores in leave)

17. Powdery Mildews

18. Downy Mildews

23. It is farther classified into following
a) Endemic Diseases
b) Epiphytotic Diseases (Epidemic Diseases)
c) Sporadic Disease

25.  Signs: mycelium, fruiting bodies
 Symptoms: necrotic areas, wilt when fungus
attacks the roots
 Phloem blockage, xylem blockage

26.  Nutrional deficiencies e.g. khaira disease of
rice due to Zn deficiency, unfavourable
environment
 e.g. frost injury, physiological wilt etc

27.  Fungi, bacteria, virus, viroids, phytoplasma,
RLBs, nematodes, higher parasitic plants etc

28.  Water is necessary for fungus infection
 Insects
 Humans
 Infected seed
 Infected soil – brought in on shoes or tractor
tires

29.  That’s all about it !
 If you have any question I would be happy
to answer.
 Thank you.