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PPN610S PLANT PROTECTION - 1ST OPP JUNE 2023 |
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n Am I BI A u n IVER s I TY
OF SCIEnCE Ano TECHnOLOGY
FACULTYOF HEALTH, NATURAL RESOURCESAND APPLIED SCIENCES
SCHOOLOF AGRICULTUREAND NATURAL RESOURCESSCIENCES
DEPARTMENT OF AGRICULTURALSCIENCESAND AGRIBUSINESS
QUALIFICATION: BACHELOR OF SCIENCE IN HORTICULTURE
QUALIFICATION CODE: 07BHOR
LEVEL: 7
COURSE CODE: PPN6 l OS
COURSE NAME: PLANT PROTECTION
SESSION:
JUNE 2023
PAPER:
THEORY
DURATION:
3 HOURS
MARKS:
100
FIRST OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S) Dr Norman Muzhinji
MODERATOR: Dr Edgar Mowa
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
PERMISSIBLE MATERIALS
1. Examination question paper
2. Answering book
THIS QUESTION PAPER CONSISTS OF 5 PAGES (Including this front page)
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Section A: Multiple choice questions (10 marks)
1. Which of the following organisms can be used as a biocontrol agent for aphids:
A. Fruit fly
B. Lacewing
C. Whitefly
D. Thrips
2. Which group of chemical products are used to control weeds in the field
A. Bactericides
B. Fungicides
C. Herbicides
D. Tutacides
3. Any cultivation will damage the crop to some extent and should be avoided when the
crop is wet. Which group of pathogens (s) will be spread most readily if a crop is
cultivated under wet conditions?
A. Bacteria
B. Viruses
C. Fungi
D. Nematodes
4. Which of the following pieces of information is not usually found on a pesticide label?
A. Active ingredient
B. Product name
C. Cost
D. Directions for use
5. Which of the following is not a feature of annual weeds?
A. Rapid growth
B. Short life cycle
C. High seed output
D. They have storage organs
6. Which of the following pathogens belongs to the oomycete group?
A. Pythium myriotylum
B. Rhizoctonia solani
C. Colletotrichum coccodes
D. Tobacco Mosaic virus
7. What are the stages of complete metamorphosis in insects?
A. Eggs,larva, pupa, adult
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B. Eggs, nymph, adult, larva
C. Pupa, nymph, adult, moth
D. Eggs, Pupa, adult, Larva
8. A weed with a long narrow leaf, parallel veins; round hollow stem and leaves are aligned
up and down the stem in two rows is called
A. Broadleaves
B. Grass
C. Sedges
D. Herbaceous
9. Which of the following is a plant disease that tends to produce only one infection cycle
per host cycle?
A. Soil-borne disease
B. Foliar diseases caused by fungi
C. Fruit diseases
D. Stem diseases
10. Which of the following is not a biotic cause of diseases
A. Bacteria
B. Insects
C. Nematodes
D. Nitrogen deficiency
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Section B: Answer all questions (90 MARKS)
1. Define or explain the following terms used in plant protection with examples.
i. Sign
[2]
ii. Pathogen
[2]
iii. Annual weed
[2]
2. a. Explain the difference between disease severity and disease incidence.
[2]
b. Show how you will calculate disease incidence.
[2]
3. List six (6) major factors to consider when planning an integrated insect control
program.
[6]
4. In March 2023, Ndonga Linena Green Scheme Irrigation, located in Rundu started to see
an increase in ·the number of cucumber plants with stunted growth followed by wilting.
Suppose you are the horticulturalist at Ndonga Linena Green Scheme responsible for
ensuring good production of horticultural crops;
a. List four (4) probable causes of cucumber wilting at the green scheme and
explain how you can identify (diagnose) each of the causes.
[8]
b. Describe the disease pentahedron and how it can be targeted to control root-
knot nematodes on tomato crops. Illustrate with a diagram.
[10]
c. Explain the difference between sedentary and migratory nematodes with
examples?
[2]
5.a Describe the difference between epidemic and pandemic diseases giving examples
of each.
[4]
b. Explain the four (4) host factors that affect disease epidemics
[8]
6. Explain how weeds are classified according to life cycle, giving an example of each class.
[8]
7. Design an Integrated Weed Management (IWM) strategy for controlling broad leaf
weeds on irrigated cabbages.
[8]
8. What is the difference between monocyclic and polycyclic disease cycles? Giving
examples.
[4]
9. Let's say in February 2023, there was an outbreak of disease Y, at Shaddy Kongolo
irrigation scheme that destroyed the whole crop in the field. Suppose you have just been
appointed as a horticulturalist responsible for overseeing production of horticultural
crops at Shaddy Kongolo and you are told disease Y is caused by either a fungus and/or a
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bacteria. You have now been assigned the responsibility of identifying the actual causative
agent of the disease.
Briefly, describe with aid of diagrams, an experiment that you would carry out to
demonstrate that disease Y is indeed caused by a fungus and/or bacteria.
[8]
Hints:
1. Use any crop of your choice commonly grown in Namibia
2. Identify a disease that commonly occur on that crop
3. Name the causative agent of that disease
4. Detail the experiment you would do to identify the causative agent and if indeed it's
the cause
10. Explain some of the causes of insect outbreaks in a crop field.
[3]
11. Sonop farm is involved in intensive production of horticultural, and ornamental plants.
Sonop farms does not have a horticulturalist and therefore has little knowledge on crop
production especially plant and crop diseases. Thy have approached you as a consulting
Horticulturalist with knowledge in plant diseases to investigate diseases occurring at its
farm. You discovered upon investigation that the plants are infected with Phytophthora
infestans, the causative agent of late blight on tomatoes.
Describe;
a. The disease cycle
[3]
b. Epidemiology of disease
[8]
THE END
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