Ahs2203:Weed Science Question Paper
Ahs2203:Weed Science
Course:Bachelor Of Horticulture
Institution: Meru University Of Science And Technology question papers
Exam Year:2013
QUESTION ONE – (30 MARKS)
a) Define the following terms: i. Weed science ( 2 Marks) ii. Allelopathy ( 2 Marks) iii. Selective herbicide ( 2 Marks)
b) Using graphs explain the differences between critical weed-free requirement and critical timing of weed removal ( 6 Marks) c) Weeds reduce the quality of harvested crop. Explain ( 3 Marks) d) (i) Differentiate eradication from weed management of methods of weed control ( 4 marks) (ii) Explain how use of smoother cops helps in controlling weeds in the farm (3 Marks)
e) Explain the three ways by which mixing of herbicides before application can affect the herbicide efficiency ( 6 Marks) f) Differentiate sympopeastic and apoplastic translocation ( 2 Marks)
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QUESTION TWO ( 20 MARKS)
a) (i) Using a diagram, explain how an apopastic herbicide applied on a leaf of a plant affects a weed plant ( 3 Marks) (ii) Differentiate tolerance from susceptibility used in weed control ( 4 Marks)
b) Plant morphological factors affects herbicides selectivity. Explain ( 13 Marks)
QUESTION THREE ( 20 MARKS)
a) Explain the behavior of herbicides once applied on the plants. ( 10 Marks) b) State and explain the various methods used for classifying weeds ( 10 marks)
QUESTION FOUR ( 20 MARKS)
(a) (i) Biological method of weed control is recommended in the world. Explain the various biological methods of weed control. ( 10 Marks) (ii) State any five disadvantages of biological weed control ( 5 Marks) b. Write short notes on contact herbicide ( 5 Marks)
QUESTION FIVE ( 20 MARKS)
a) State any five modes of action of herbicides ( 5 Marks) b) Physical factors influences the contact between the herbicide and the plant surfaces. Give a detailed description of the above. ( 10 Marks) c) Water management can be used as a method of weed control. State any three methods of water management used for weed control. ( 3 Marks) d) State any two ways used for classifying weeds according to human values ( 2 Marks)
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