LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PLANT BIOLOGY & PLANT BIO-TECH.
SIXTH SEMESTER – April 2009
VE 20
PB 6604 - PLANT DISEASES AND MANAGEMENT
Date & Time: 18/04/2009 / 9:00 - 12:00
Dept. No.
Max. : 100 Marks
PART – A (20 MARKS)
I. CHOOSE THE CORRECT ANSWER:
(5 x 1 = 5)
o
1. The most resistant virus, whose thermal deathpoint is 90 C for 10mts.
a.
Tungrovirus, b. Potatovirus, c. CMV,
d. TMV
2. It is an ulcer like lesion on fruit, tuber, leaves; as an outgrowth of cortical & epidermal
cells.
a.
Scab b. Edema,
c. callus
d. Tumour
3. Teleutospores are
a.
Unicellular
b. bicellular binucleate
c. unicellular bi nucleate
d. bicellular uninucleate
4. The fruit becomes grayish and the skin hardens and c shrivels in
a.
Downy mildew on grapes
b. citruscanker
c. little leaf of brinjal
d. Tikka of groundnut
5. The smut fungi belongs to the order.
a.
Ustilaginales, b. Uredinales c. Peronosporales
d. Mucorales
II. COMPLETE THE FOLLOWING :
(5 x1 = 5)
6. Parasitic algae in plant is ________________________.
7. _________________ is a substance produced by a pathogen, which inhibits the
development of defence reaction in plants.
8. In response to wounding _______________ is the tissue overgrowth as a healing process.
9. Clubroot of cabbage is caused by ______________.
10. ___________________ are Necrotic lesions on the fruits.
III. STATE WHETHER THE FOLLOWING STATEMENTS ARE TRUE OR FALSE:
(5 x 1 = 5)
11. Viroids are infective nucleic acids, similar to virus, and has a protein covering.
12. Neem cake is very effective in reducing root knot incidence.
13. Colletotriclurm falcatum can be effectively controlled by Bavistin, Topsin, and by
Bordeaux mixture.
14. Sulphur is a good fungicide.
15. Plant pathogenic bacteria are mostly grain positive.
IV. ANSWER THE FOLLOWING IN 50 WORDS EACH:
16. Define Inoculam Potential.
17. What are the symptoms of Blight Disease.
18. What is Epidemiology?
19. Describe bacterial gall.
20. Mention any one symptom of viral Disease on plants?
(5 x 1 = 5)
PART-B
ANSWER ANY 5, EACH NOT MORE THAN 350 WORDS:
(5 x 8 = 40)
21. Explain Epidemics & Endemics.
22. Write down Koch’s Postulates.
23. Explain the inanimate causes of diseases in crops.
24. Explain Hyper Trophy & Hyperplasia, Giving Examples.
25. Write about Tungro disease of Rice.
26. Write notes on Ergot of rye.
27. Write notes on crop protection and Induced resistance.
28. Write about the characters of Mycoplasmas.
PART-C
ANSWER THE FOLLOWING IN NOT MORE THAN 1500 WORDS EACH: (2 x 20 = 40)
29. Explain the pathological life cycle of wilt of cotton.
OR
Explain the pathological life cycle of Rust of wheat
30. Write about the Environmental impacts on Disease development and Epidemics.
OR
Write notes on 1. Plant Quarantine Principles.
2. Disease Forecasting
3. Seed and Soil Treatments.
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