2024 Lecture 4-6 AGRI1664 Principles Of Plant Pathology PDF

AGRI1664 | PRINCIPLES OF PLANT PATHOLOGY Lecture 4-6 Dr Lisa Rothmann Biology Building, Room 300 [email protected] Department of Plant Sciences University of the Free State Biology Build...

AGRI1664 | PRINCIPLES OF PLANT PATHOLOGY Lecture 4-6 Dr Lisa Rothmann Biology Building, Room 300 [email protected] Department of Plant Sciences University of the Free State Biology Building 300 1 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Discuss the reality of plant diseases in our daily lives Define plant disease & explore the disease triangle Characterise organisms involved in causing disease Compare disease cycles Identify how agricultural systems affect disease development and Define intervention practices to prevent, manage and control plant diseases Pietersen et al., 2009 2 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Lecture 4 3 3 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Diseases that include a single infection cycle of the pathogen during a crop cycle are termed monocyclic diseases. Pietersen et al., 2009 4  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC The ability of the pathogen to persist in the environment between growing seasons or during unfavorable conditions. This can occur in various forms, such as dormant structures (e.g., spores, sclerotia) or as a residual pathogen in the soil or plant debris. Pietersen et al., 2009 5 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC The initial source of pathogen inoculum that initiates the infection in a new crop cycle. Pietersen et al., 2009 6  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC The movement of primary inoculum from its source to the infection court. Dispersal can occur through various mechanisms such as wind, water, or animal vectors, depending on the type of pathogen and its mode of spread. Pietersen et al., 2009 7  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC The movement of primary inoculum from its source to the infection court. Dispersal can occur through various mechanisms such as wind, water, or animal vectors, depending on the type of pathogen and its mode of spread. Pietersen et al., 2009 8  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC The specific part of the plant that is susceptible to infection. This is the site where the pathogen encounters and infects the plant. For many diseases, this is the leaf, stem, or root where the pathogen's inoculum lands and begins to infect. Pietersen et al., 2009 9  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Infection refers to the process by which the pathogen penetrates and establishes itself in the plant tissue. Colonisation is the subsequent growth and spread of the pathogen within the plant tissue, leading to symptom development and potentially further spread of the disease. Pietersen et al., 2009 10  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Infection refers to the process by which the pathogen penetrates and establishes itself in the plant tissue. Colonisation is the subsequent growth and spread of the pathogen within the plant tissue, leading to symptom development and potentially further spread of the disease. Pietersen et al., 2009 11 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC 12 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Lecture 5 13 13  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Alternative host Adre Minnaar-Ontong et al., 2020; Meyer et al., 2021 14 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Emge, 1958 and Ingold, 1961; taken From Zadoks & Schein, 1979 15  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Germ tube Spore Appressorium Infection hyphae & Haustoria Pietersen et al., 2009 16 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Pietersen et al., 2009 17 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Necrotroph Pietersen et al., 2009 18 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Mycotoxin Pietersen et al., 2009 19 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Mycotoxin Pietersen et al., 2009 20 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Pietersen et al., 2009 21 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Biotrophic Pietersen et al., 2009 22 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Vector Pietersen et al., 2009 23 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Latent infections Pietersen et al., 2009 24 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Lecture 6 25 25  OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Disease that include more than one infection cycle of the pathogen during a crop cycle are termed polycyclic diseases. Pietersen et al., 2009 26 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Pietersen et al., 2009 27 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Alternate host Pietersen et al., 2009 28 OUTCOMES MONOCYCLIC INFECTION POLYCYCLIC Pietersen et al., 2009 29