Lesson Note on Pests and Diseases of Crops: Life Cycle and Control Methods for SSS 2

Class: Senior Secondary School 2 (SS2 / SSS2)
Term: 2nd Term
Week: 3
Age: 16 years
Duration: 45 minutes
Subject: Biology
Curriculum Theme: Applied Biology and Health
Previous Lesson: Pests and Diseases of Crops: Definition and Classification.
Topic: PEST AND DISEASES OF CROP
Subject Matter: Life cycle and control of pest, diseases caused by pest and their agents viral bacterial and fungi disease, methods of pest and disease control physical biological and chemical methods.

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

• Define agricultural pests and crop diseases.
• Identify different types of crop diseases based on their causal agents.
• List various methods used for controlling pests and diseases.

Affective Domain:

• Appreciate the economic importance of controlling pests and diseases in agriculture.
• Show concern for the impact of pests and diseases on food production.
• Develop interest in sustainable pest and disease management practices.

Psychomotor Domain:

• Illustrate the life cycle stages of a common agricultural pest.
• Propose appropriate control methods for specific pest and disease problems.
• Participate in discussions about local pest and disease challenges.

Social Domain:

• Discuss the role of community in preventing the spread of crop diseases.
• Collaborate with peers to identify solutions for pest and disease problems.

Reference Materials

The following resources were used in planning this lesson:

• Senior Secondary Schools Education Curriculum
• State Unified Scheme of Work
• Essential Biology for Senior Secondary Schools by M.C. Michael
• Biology textbooks and relevant charts.

Instructional Materials

The teacher will teach this lesson with the aid of:

• Textbook
• Posters showing various pests and diseased plants
• Charts illustrating the life cycle of common pests (e.g., grasshopper, butterfly).

Rationale for the Lesson

This lesson helps pupils understand how pests and diseases affect crop production and food security. It enables them to identify different types of crop damage and learn practical methods to protect crops, which is important for agricultural sustainability and economic well-being.

Prerequisite/Previous Knowledge

Pupils are expected to have basic knowledge of plant parts, plant growth, and the importance of agriculture from their previous biology lessons.

Lesson Content/Board Summary

PEST AND DISEASES OF CROP

Definition of Pests and Diseases

Pests are organisms that cause damage to crops, stored food, or livestock, thereby reducing yield or quality. Examples include insects, rodents, birds, and nematodes.

Diseases in crops are conditions that impair the normal functioning of a plant, leading to symptoms like wilting, discolouration, stunted growth, or death. They are caused by pathogenic organisms or environmental factors.

Life Cycle of Pests (Example: Grasshopper)

The grasshopper undergoes incomplete metamorphosis, meaning it has three main stages:

• Egg: Laid in soil, usually in pods.
• Nymph: Hatches from the egg, resembles a smaller, wingless adult. It undergoes several molts (instars) as it grows.
• Adult: Fully developed with wings and reproductive organs.

Types of Crop Diseases by Causal Agent

Crop diseases are primarily caused by different types of pathogens:

• Viral Diseases: Caused by viruses. They often lead to symptoms like mosaic patterns on leaves, yellowing, or stunted growth. Examples include Tobacco Mosaic Virus (TMV).
• Bacterial Diseases: Caused by bacteria. Symptoms can include leaf spots, blights, cankers, soft rots, and wilting. Examples include Bacterial Blight of cotton.
• Fungal Diseases: Caused by fungi. These are common and manifest as rusts, smuts, mildews, leaf spots, and root rots. Examples include Cassava Anthracnose, Maize Rust.

Methods of Pest and Disease Control

Various methods are employed to manage pests and diseases, often in an integrated approach:

• Physical Methods: These involve direct removal or creation of physical barriers.
  • Hand picking of pests or diseased plant parts.
  • Trapping (e.g., sticky traps, pheromone traps).
  • Trenching to prevent spread of crawling pests.
  • Burning of severely infected plants.
  • Crop rotation.
  • Pruning and weeding.
• Biological Methods: Involve the use of natural enemies or beneficial organisms to control pests.
  • Introduction of predators (e.g., ladybirds to eat aphids).
  • Use of parasites (e.g., parasitic wasps).
  • Pathogens (e.g., bacteria or fungi that infect pests).
  • Sterile insect technique.
• Chemical Methods: Involve the use of pesticides and fungicides to kill or inhibit pests and pathogens.
  • Insecticides (to kill insects).
  • Fungicides (to control fungal diseases).
  • Herbicides (to control weeds, which can harbour pests).
  • Rodenticides (to kill rodents).
  • Careful application is needed due to environmental and health concerns.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher asks pupils what they understand by “pests” and “diseases” in the context of agriculture and why it is important to control them.
Pupils’ Activity: Pupils share their prior knowledge and ideas about agricultural pests and diseases.
Learning Point: Pupils recall and connect previous knowledge to the new topic.

Step 2: Definition of Pests and Diseases

Time: 7 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines agricultural pests and diseases, providing examples relevant to local farming.
Pupils’ Activity: Pupils listen attentively, take notes, and ask questions for clarification.
Learning Point: Pupils understand the basic definitions of pests and diseases.

Step 3: Life Cycle of Pests

Time: 10 minutes
Teaching Skill: Illustration/Description
Teacher’s Activity: The teacher uses a chart or diagram to illustrate and explain the life cycle of a common pest (e.g., grasshopper), highlighting the stages where they cause damage.
Pupils’ Activity: Pupils observe the charts, describe the stages, and discuss how different stages affect crops.
Learning Point: Pupils can trace the life cycle of a pest and identify its damaging stages.

Step 4: Types of Crop Diseases

Time: 7 minutes
Teaching Skill: Categorization/Explanation
Teacher’s Activity: The teacher explains different types of crop diseases based on their causal agents (viral, bacterial, fungal), giving examples for each.
Pupils’ Activity: Pupils identify and differentiate between viral, bacterial, and fungal diseases from the teacher’s explanation.
Learning Point: Pupils understand the various agents causing crop diseases.

Step 5: Methods of Pest and Disease Control (Physical)

Time: 5 minutes
Teaching Skill: Listing/Discussion
Teacher’s Activity: The teacher introduces and discusses physical methods of pest and disease control, giving examples.
Pupils’ Activity: Pupils identify and list various physical control methods.
Learning Point: Pupils learn about non-chemical ways to manage pests and diseases.

Step 6: Methods of Pest and Disease Control (Biological & Chemical)

Time: 6 minutes
Teaching Skill: Explanation/Comparison
Teacher’s Activity: The teacher explains biological and chemical control methods, discussing their advantages and disadvantages.
Pupils’ Activity: Pupils discuss the pros and cons of biological and chemical control, identifying situations where each might be suitable.
Learning Point: Pupils understand the principles and applications of biological and chemical control.

Step 7: Evaluation/Review

Time: 5 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define agricultural pests and crop diseases.
2. List three types of crop diseases based on their causal agents.
3. Mention two physical methods of pest control.
4. Explain one biological method of disease control.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson and assigns homework, which could include researching local crop pests and their control.
Pupils’ Activity: Pupils listen to the summary and copy down their homework assignment.
Learning Point: Pupils reinforce their understanding and prepare for further study.

Lesson Keywords

• Pest – An organism that damages crops or livestock.
• Disease – An impairment of a plant’s normal function caused by pathogens or environment.
• Pathogen – An organism (like a virus, bacterium, or fungus) that causes disease.
• Life cycle – The series of changes in the life of an organism.
• Control methods – Techniques used to manage or reduce pest and disease populations.

Differentiation

For pupils who grasp concepts quickly, the teacher can challenge them to research and present on specific indigenous pest control methods. For those needing more support, the teacher can provide simplified diagrams and allow for peer tutoring or group work to reinforce understanding.

Note for teachers using this lesson plan

Teachers should use local examples of pests and diseases relevant to the pupils’ community to make the lesson more relatable and practical. Encourage pupils to share their experiences or observations from their homes or farms regarding crop protection.