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PPN610S - PLANT PROTECTION - 2ND Opp - JULY 2022 |
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n Am IBIA u n IVERs ITY
OFSCIEnCEAno TECHnOLOGY
FACULTYOF HEALTH,APPLIEDSCIENCESAND NATURALRESOURCES
DEPARTMENTOF AGRICULTUREAND NATURALRESOURCESSCIENCES
QUALIFICATION: BACHELOROF SCIENCEIN HORTICULTURE
QUALIFICATION CODE: 07BHOR
LEVEL: 6
COURSE:PLANT PROTECTION
COURSECODE: PPN610S
DATE: JULY2022
SESSION:JULY
DURATION: 3 HOURS
MARKS: 100
SECONDOPPORTUNITYEXAMINATION QUESTION PAPER
EXAMINER: Dr N. Muzhinji
MODERATOR: Dr E. Mowa
THIS EXAMINATION PAPERCONSISTSOF 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
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Section A: Multiple choice questions (8 marks)
1. Any cultivation will damage the crop to some extent and should be avoided when the crop is
wet. Which group of pathogen (s) will be spread most readily if a crop is cultivated under wet
conditions?
A. Bacteria
B. Viruses
C. Fungi
D. Nematodes
2. 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
3. Which ofthe following is not a feature of annual weeds?
A. Rapid growth
B. Short life cycle
C. High seed output
D. They have storage organs
4. Which choice would be an example of a biological method of pest control?
A. Applying a pre-emergence herbicide
B. Cultivating between rows
C. Crop rotation
D. Increasing the population of the pest's natural enemy
5. What are the stages of complete metamorphosis in insects?
A. Eggs, larva, pupa, adult
B. Eggs, nymph, adult, larva
C. Pupa, nymph, adult, moth
D. Eggs, Pupa, adult, Larva
6. 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. Broad leaves
B. Grass
C. Sedges
D. Herbaceous
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7. 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
8. Which of the following is not a biotic cause of diseases
A. Bacteria
B. Insects
C. Nematodes
D. Nitrogen deficiency
Section B: Answer all questions (92 MARKS)
1. Define or explain the following terms used in plant protection with examples.
i. Sign
[2]
ii. Pathogen
[2]
iii. Annual weed
[2]
iv. Systematic insecticide
[2]
v. Post-emergence herbicide application
[2]
2. a. Explain the difference between disease severity and disease incidence
[2]
b. Show how you will calculate disease incidence
[2]
3. Briefly, explain the impact of plant pests to the horticultural sector in Namibia.
[S]
4. Differentiate between quantitative and qualitative yield losses caused by crop pests. Give
examples
[4]
5. List six (6) major factors to consider when planning an integrated insect control program [6]
6. In January 2022, Etunda Green Scheme Irrigation, located in Ruacanaa started to see an increase
in the number of tomato plants with stunted growth followed by wilting. Laboratory diagnosis
of the plants identified root-knot nematodes (RKN)as the cause of this disease. Suppose you are
the farm supervisor at the Etunda Green Scheme Irrigation responsible for ensuring good crop
production of horticultural crops,
a. List three (3) factors that must be present for the disease (wilting) to occur
[3]
b. Describe the disease pentahedron and how it can be targeted to control root-knot
nematodes on tomato crops
[8]
c. Explain the difference between sedentary and migratory nematodes with examples?
[2]
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7.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]
8. Describe how weeds are classified according to life cycle; giving an example of each class.
[8]
9. Write brief notes to the beneficiaries of Mashare irrigation scheme explaining why it is
necessary to remove weeds and volunteer plants promptly from their fields.
[4]
10. Design an Integrated Weed Management (IWM) strategy for controlling broad leaf weeds
on irrigated cabbages
[8]
11. What is the difference between monocyclic and polycyclic disease cycles? Giving examples
[4]
12. Tomato crop in the greenhouse in Mariental has been infected with leaf and fruit spot
disease. The disease reduced the growth of the tomato plants and rendered the fruits
unmarketable. As a horticulturalist responsible for that region, you are tasked to investigate
the actual cause of the disease. The symptoms appear like those caused by
viruses/bacteria/fungi and you are not sure of the causative agent. You then decide to take
the plant to a plant diagnostic laboratory in Windhoek for testing.
a. Describe the nature of the sample that you would submit for testing and any other
accompanying information that will assist in accurate identification of the
disease/pathogen
[5]
b. Imagine yourself as part of a diagnostic team in the laboratory, detail all the steps that you
would take to identify the cause of the problem correctly and accurately.
[6]
13. Explain some of the causes of insect outbreaks in a crop field.
[3]
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