Weeds II: Meaning, Types, Examples and Economic Importance


Welcome to Class !!

We are eager to have you join us !!

In today’s Agricultural Science class, We will be learning about Control of Weeds. We hope you enjoy the class!


common types of weed agric science classnotesng



  1. Mechanical control: involves the use of machines such as bulldozer, tree puller, plough etc to get rid of unwanted plants.
  2. Physical or manual control: This can be done in different ways which include hand pulling, hoeing, slashing with cutlass etc.
  3. Biological Control: This involves the introduction of some insects and herbivorous animals to farmland to eat up the leaves of the weed and even the entire plant in some cases.
  4. Cultural control: This involves the use of a farming system to get rid of weeds. It can be achieved by the practice of crop rotation and the growing of cover crops to suppress the growth of the weeds on the farm. Other types of cultural weed control methods are: flooding, bush burning, mulching
  5. Chemical Control: This involves the use of a chemical solution called herbicides to control weeds. Some herbicides are selective while some are non-selective or contact herbicide

weeding postplanting operations classnotesng



  1. They have vigorous growth, they are aggressive and persistent
  2. Weeds have high reproductive capacity
  3. Their seeds have a long period of viability
  4. Weeds have efficient dispersal method
  5. They have efficient means of propagation
  6. They have a long period of dormancy
  7. They produce many seeds
  8. They have a short life cycle



  1. What are weeds?
  2. Discuss the methods of weed dispersal
  3. List five economic importance of weeds
  4. List five common weeds and state their botanical names
  5. Discuss the four methods of weed control
  6. Give three reasons why weeds are difficult to eradicate



  • Essential  Agricultural Science for Senior Secondary School by O.A. Iwena Chapter 28 pages 249-260
  • Answer the following questions from WAEC PAQ 2005 theory question 5



  1. What are weeds
  2. Describe four methods of weed control
  3. List four benefits of weeds to farmers
  4. State four reasons why weeds are difficult to control



We have come to the end of this class. We do hope you enjoyed the class?

Should you have any further question, feel free to ask in the comment section below and trust us to respond as soon as possible.

In our next class, we will be learning about Crop Improvement. We are very much eager to meet you there.


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