U.G. DEGREE EXAMINATION – PLANT BIOLOGY & BIOTECHNOLOGY
SIXTH SEMESTER – APRIL 2012
PB 6608/PB 6604 – PLANT DISEASES AND MANAGEMENT
Date : 16-04-2012
Time : 1:00 - 4:00
Dept. No. Max. : 100 Marks
PART – A
Answer the following each in about 50 words :
1. Define infection.
(10 x 2 = 20)
2. What is meant by secondary inoculums?
3. What are phytoalexins?
4. What is hypersensitivity.
5. Write about the causal organism for Club root of cabbage.
6. What is Acervulus?
7. Name the pathogen and control measure for Blight of rice.
8. Write notes on galls.
9. Give the composition of Bordeaux mixture.
10. What is meant by Field sanitation?
PART – B
Answer the following each answer not exceeding 500 words :
Draw diagrams wherever necessary:
11. a. Discuss the role of growth regulators in the development of plant disease. b. Explain Koch’s postulates.
(or)
12. a. Discuss the role of light and temperature in disease development.
(or)
b. Write notes on:
(i) Natural openings
(ii) Deposition of gums
13. a. Write an account on Tikka disease of groundnut.
(or)
b. Describe briefly about the disease caused by Puccinia graminis tritici .
14. a. Briefly describe any one viral disease you have studied.
(or)
b. Write short notes on Cuscuta.
(5 x 7 = 35)

15. a. Give an account of quarantine regulations.
(or)
b. Explain soil and seed treatment for eradication of plant diseases.
PART – C
Answer any three of the following each answer not exceeding 1200 words .
Draw diagrams wherever necessary. (3 x 15 = 45)
16. Describe the morphological and anatomical changes in the host plant due to pathogenesis.
17. Give a detailed account on Induced histological defence mechanism.
18. Discuss in detail about Blast of rice.
19. Explain the pathogen, symptoms and control measures of Citrus canker.
20. Write an essay on the biological control of plant diseases.
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