Lesson Plan: Plant Diseases and Climate Change

Here is a step-by-step guide to using this lesson plan in the classroom/laboratory. We have suggested these steps as a possible plan of action. You may customize the lesson plan according to your preferences and requirements.

Step 1: Introduce the topic by playing a micro-lecture (video)

1. Play the video micro-lecture, ‘Introduction to Plant Diseases of Field Crops ‘, by Dr. Damon Smith from University of Wisconsin, Integrated Crop and Pest Management, to introduce the topic of plant disease.
2. Use the video to describe various causal agents (pathogens) that are responsible for the development of disease in plants.
3. Describe the course of pathogenesis in plants due to pathogens such as viruses, bacteria, nematodes and fungi.
4. Use the video to recognize how plant disease differs from plant disorders.
5. Emphasize on the significance of the host-pathogen-environment triangle for the healthy growth of plants.
6. Finally, discuss how targeted disease management strategies are employed for crop security.

Go to the Video (up to 19.30 min)

Step 2: Explain the effect of climate change on plant disease

1. Use the reading, ‘The Effect of Climate Change on Plant Diseases’, by Yáñez-López et al (2012), African Journal of Biotechnology, 11(10), 2417-2428, to explain how climate change impacts pathogenesis in plants.
2. Explain that climate can affect the developmental stages of pathogens, the dispersal of pathogens, and the geographical distribution of hosts and pathogens.
3. Thus, discuss how climate change related factors such as global warming and increasing atmospheric carbon dioxide concentrations can affect plant-pathogen interactions.
4. Describe how the changing plant disease distribution and occurrence rates results in greater crop losses and affect food security.
5. Finally discuss how sustainable food production with disease management strategies could be directed for a changing climate.

Go to the Reading

Step 3: Extend the understanding

1. Use this activity, ‘Disease Plant Walk’, by the American Pathological Society, to teach your students about the signs and symptoms of disease in plants.
2. Distinguish between healthy and diseased plants. Extend the students’ understanding of host-pathogen interactions by identifying different diseases in the observed plants and discussing their causal agents.
3. Direct your students to record their observations and to do a follow-up set of observations (after a few days or weeks), in order to note how the disease progressed in these plants.
4. Encourage your students to analyze the recorded observations using parameters such as the host-pathogen-environment triangle and the temporal and spatial distribution of disease.
5. Emphasize on the role of environmental factors on the severity of disease and disease progression.
6. Extend the discussion to include climate change related factors such as global warming and increased atmospheric carbon dioxide concentrations and their possible impacts on plant disease, which in turn can affect crop/food security.

Go to the Activity

Use the tools and the concepts learned so far to discuss and determine answers to the following questions:

1. What is plant disease? How does it differ from plant disorders?
2. What are the primary causal agents of disease in plants?
3. What are plant pathogens?
4. What are the signs and symptoms of plant disease?
5. How do changing climatic conditions impact the development and spread of disease in plants?

The tools in this lesson plan will enable students to:

1. define what are plant diseases and what are the factors influencing it
2. classify the various causal agents of disease in plants
3. distinguish between signs and symptoms of diseases in plants
4. describe the pathology of diseases caused by bacteria, viruses, fungi and nematodes in plants
5. understand the balance of the host-pathogen-environment triangle
6. discuss how climate change can impact the development of plant disease