Pest and diseases of crop plants

Pests are animals that damage agricultural produce by feeding on them. Common pests of crops are insects, birds, bats, rodents and monkeys. Diseases are abnormalities in the growth of crops. Common diseases of crops include

Maize smut, groundnut rosette, cassava mosaic, tomato rot, yam rot, cassava leaf blight and rice smut. Pests and diseases have these adverse effects on the growth and development crop plants:


  1. Pests reduce the growth of crop plants by eating up their leaves.
  2. Pests and diseases reduce the yield of crop plants by reducing the quality of fruits and seeds harvested.


  1. They reduce the quality of farm produce and stored grains.
  2. Some pests transmit diseases to human by poisoning and contaminating harvested produce of crop plants meant for human consumption. Crop plants mostly affected by pests and diseases arE cereals, tubers, legumes, fruits and vegetables



The pests that affect them are







Insect pests

The insects that damage cereal crops include stem borers, weevils and army worms. The stem borer damages the crops by boring holes into, and chewing the stems of maize, sugarcane, sorghum and rice. It also damages the cobs of maize.



The common rodents that damage cereal crops are rats and grass cutters. They also damage the young seedlings of cereal crops.



Common birds that damage cereal crops include weaver birds, quells and bush fowls. Weaver birds eat up mature grains of cereals, such as rice, maize and guinea corn. They also tear off parts of the leaves of the crops for making their nests. This reduces the yield of crops. Bush fowls feed on mature grains of cereal crops.


Methods of controlling pests  

  1. Maintain adequate farm hygiene.
  2. Plant crops in time.
  3. Treat seeds with protective chemicals.
  4. Trap and kill rodents.
  5. Use scarecrows to keep off birds.


Strategies & Activities:

Step: Teacher revises the previous topic.

Step 2: Teacher introduces the new topic.

Step3: Teacher explains the new topic.

Step4: Teacher welcomes pupils questions.

Step5: Teacher evaluates the pupils.


Assessment & Evaluation:

  1. Define pest and diseases.
  2. List some common pest and diseases
  3. Mention the effect of pest and diseases
  4. State the method of controlling pest.



  1. List four crop diseases and the agents that cause them.
  2. Name five common pests of farm animals. Mention and describe the damage they do to crops.
  3. List three specific methods of controlling pests of tuber crops.
  4. List three specific methods of controlling diseases of cereal crops.5.
  5. List three adverse effects of using chemicals to control pests of crop plants

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