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PPN610S - PLANT PROTECTION - 1st Opp - JUNE 2022 |
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r
n Am I BIA u n IVERsITY
OFSCIEnCEAno TECHnOLOGY
FACULTYOF HEALTH,APPLIEDSCIENCESAND NATURALRESOURCES
DEPARTMENTOF AGRICULTUREAND NATURALRESOURCESSCIENCES
QUALIFICATION: BACHELOROF SCIENCEIN HORTICULTURE
QUALIFICATION CODE: 07BHOR
LEVEL: 6
COURSE:PLANT PROTECTION
COURSECODE: PPN610S
DATE: JUNE 2022
SESSION:JUNE
DURATION: 3 HOURS
MARKS: 100
FIRSTOPPORTUNITYEXAMINATION QUESTION PAPER
EXAMINER: Dr N. Muzhinji
MODERATOR: Dr E. Mowa
THIS EXAMINATION PAPERCONSISTOF FOUR (4) PAGES
(INCLUDING THIS FRONT PAGE)
INSTRUCTIONS
1. All examination RULESapply
2. Read all the questions carefully before answering
3. Marks are indicated at the end of each question
4. Write clearly and neatly
5. All written work MUST be done in BLUEor BLACKink
PERMISSIBLEMATERIALS
None
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Section A: Multiple choice questions (6 marks)
1. What was the causal pathogen of the Irish potato famine of 1845-1846?
A. Alternaria tomatophi/a
B. Botrytis cinerea
C. Phytophthora infastens
D. Meloidogyne javanica
2. Which of the following pathogens belongs to the oomycete group?
A. Pythium myriotylum
B. Rhizoctonia solani
C. Col/etotrichum coccodes
D. Pectobacterium carotovorum
3. Which development stage of an insect is most damaging to the crops?
A. Pupae
B. Larvae
C. Adult
D. Eggs
4. Rust on the leaf is a sign of
A. Bacteria
B. Fungi
C. Virus
D. Nematodes
5. Which of the following plant diseases produce only one infection cycle per host cycle
A. Soil-borne disease
B. Foliar diseases caused by fungi
C. Fruit diseases
D. Stem diseases
6. Insecticides that act by permeating the entire plant are said to be:
A. Porous insecticides
B. Penetrating insecticides
c. Contact poisons
D. Systematic insecticides
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Section B: Answer all questions (94 MARKS)
1 a. Name a plant disease of your choice and explain the aetiology and epidemiology of the
disease and recommend appropriate recommended control measures.
[20]
b. Explain the importance of epidemiology in disease management?
[4]
2. Using your own examples of pest/ disease and crop; explain how crop rotation can be
used to control pest and plant diseases.
[10]
3. a. Name four advantages of using biological pest control methods.
[2]
b. List three (3) precautions to keep in mind when using chemical control measures.[3]
4. Tomato spotted wilt (caused by tomato spotted wilt virus) is generally considered a
monocyclic disease of tomatoes. Explain what this means.
[2]
5. Damping-off is a disease that affects seedlings in the nursery.
a. Describe the symptoms of damping-off on seedlings and factors favouring its
development.
[4]
b. Describe the integrated pest management of damping-off in the nursery seed bed.
[4]
6. a. What are the three ways that a plant virus can be transmitted from one plant to
another in a field?
[3]
c. Why is management of plant viral diseases always based on prevention, rather than
curing?
[2]
d. A potato grower in Tsumeb sprayed his virus infected potato plants with a pesticide.
Is the use of pesticides to control viruses in the field a correct procedure? Yes or No.
Justify your answer.
[2]
e. Suggest to the farmer any three strategies that he can use to prevent future outbreak
of viral diseases in his potato field.
[3]
7. a. Explain why weeds are a problem in conservation agricultural systems? Explain in
detail how you would address the problem.
[6]
b. Weeds can be controlled by mechanical and biological methods. For each of these
methods, describe the advantages and disadvantages.
[8]
8. a. Tuta absoluta is one of the most destructive pests in Namibia causing yield losses in
potato and tomato production. What will be the disadvantages of using insecticide for
controlling Tuta absoluta on potato?
[4]
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b. As a horticulturalist responsible for production of quality tomatoes and potatoes at
Mashare irrigation scheme, you have been using insecticides to control Tuta absoluta
in potato fields for several years, but it's no longer effective. Explain two possible
causes of what could have led to this development and discuss ways you would deal
with such a situation.
[10]
9. Explain the importance of forecasting in managing plant diseases.
[3]
10. Mention any four strategies that you would use to reduce the primary sources of
inoculum of any pathogen of your choice.
[4]
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