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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI 600 034
B.Sc.DEGREE EXAMINATION -PLANT BIOLOGY AND PLANT BIOTECHNOLOGY
FIFTH& SIX SEMESTER APRIL 2018
PB 5523/ PB 6608 PLANT DISEASES MANAGEMENT
Date: 03-05-2018 Dept. No. Max. 100 Marks
Time: 09:00-12:00
PART A
Answer the following, each within 50 words only (10x2=20)
1. Comment on Koch's postulates?
2. What is inoculum potential?
3. What is tylosis?
4. What is cross protection?
5. What is damping off?
6. Write note on causal organism of rice blast?
7. What is TMV?
8. Give the symptoms for little leaf of brinjal.
9. What is plant quarantine?
10. What is collateral host?
PART B
Answer the following, each answer within 500 words, draw diagrams wherever necessary:
11. a. Describe the role of toxins in plant disease development.

b. How are diseases of plants classified?
12. a. Summarise the barriers of the host that resist infection.

b. Discuss the role of environmental factors in disease development.
13. a. Write about the causal organism, symptoms and control measures of tikka disease.

b. Write about ergot of rye.
14. a. Write an account on the nematode infection.

b. Write about the causal organism, symptoms and control measures of citrus canker
15. a. Describe the cultural practices adopted in plant disease management.
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b. Write an account on disease forecasting.
PART C
Answer any three of the following, each within 1200 words, draw diagrams wherever necessary: (3x15=45)
16. Write an essay on host parasite interaction in disease development
17. Describe the role of biochemicals in disease control
18. Write about the causal organism, symptoms and control measures of wheat rust.
19. Write notes on: Tungro mosaic virus Cuscuta Galls.
20. Write an essay on the engineering of disease resistance character in corps.