1. PRINCIPLES OF PLANT INFECTION
DR. RAJBIR SINGH
Assistant Professor
Department of Plant Pathology
Gochar Mahavidyalaya, Rampur Maniharan, Saharanpur (UP), India
Affiliated to Ch. Charan Singh University, Meerut (UP), India
Email: rajbir25805@yahoo.com, rajbirsingh2810@gmail.com
Cell No. 91-9456613374
2. (A). Penetration - “Entry of pathogen in
the host is called penetration”
(i). Direct penetration
fungi, nematodes & parasitic pls.
Mechanic forces & enzymatic softening
By appressorium in fungi
6. (ii). Through wounds
All bacteria, most fungi, some virus & viroid
Enter through wounds
Virus, MLO, RLO enter through wounds made
by vector
iii). Through natural opening
(a). Stomata
Many fungi & bacteria enter through stomata
8. (b). Hydathodes
are more or less permanently open pores at
the end on the tip of leaves
Bacteria enter through hydathodes
9.
10. (c). Lenticels
Are openings on fruits, stem, tubers that
are filled with loosely connected cells to
allow passage of air
Few fungi and bacteria enter through lenticels
11. (B). Infection
“The establishment of a pathogen with in a host
plant”
“Infection is the process by which pathogen
establish contact with susceptible cell or
tissues of the host and procure nutrients
from them”
12. (C). Invasion
“ The spread of the pathogen with in the host”
Fungi spread - Intercellular, intercellular
Bacteria - Intercellular, intercellular
Virus, virods, MLO, phytoplasma & RLO
By moving from cell to cell interacellularly
13. (D). Dissemination or Dispersal of
Pathogen
(A). Autonomous Dissemination
(1). By Soil
(2). By Seeds
(3). By Plant and Plant Parts