Plant Pathology — DU B.Sc. (Hons.) Botany Previous Year Question Papers

Paper no. - 503 SET B 3. Draw diagrams wherever required. l 1. (a) Define the following: (1x5=5) (ii) Incubation period (iii) Hypoplasia (iv) Epiphytotic disease (b) Fill in the blanks; (1x5=5) i. Aecial stage develops in rust disease on - - host. ii. A spherical and granular cytoplasmic body in the centre of the oosphere of Albugo is known as --. ill. Brand spores are formed in - --- disease. iv. ...is the causative agent of the Root knot disease of Brinjal. V. • is a simple or branched projection of hyphae into host cells that act as an absorbing organ. (c) State whether the following statements are true or false: (1x5=5) (i) Anton de Bary is known as the father of modern mycology and plant pathology. (ii) Bordeaux mixture is an example of an organic fungicide. (iii) The disease pyramid includes the components: host, pathogen, environment, and time. (iv) Plant quarantine helps prevent the introduction and spread of exotic plant diseases. (V) . Vein clearing of bhindi is a fungal disease transmitted through soil. Q2. Differentiate between the following (any three): (5x3= 15) (a) Primary host and secondary host (b) Systemic and localised infection (c) Powdery and downy mildew of discase (d) Rust and Smut discase @ 4. Write short notes on the following (any three): (5x3= 15) (a) Koch's Postulates (C) Cultural practices of plant disease control (d) Plant quarantine regulations Q 5. (a). Explain sexual mode of reproduction in Phytophthora infestans with suitable diagram. (7.5) (b). Discuss the role of systemic fungicides in modern plant disease management. Q 6. (a) Give a brief account about the Plant defence mechanisms (Constitutive and induced, structural and biochemical) with one suitable example each. (7.5)