Notes: These assignments require each student to write a paragraph (introductory sentence, body, concluding sentence) and can be completed in 10–15 minutes in class. They provide a good way to check student comprehension and to improve student writing skills. See Chapter 1 for a simple grading system.
1) Roles of People in Plant Disease Epidemics
You have now learned about historically important epidemics of four different plant diseases: late blight of potato, downy mildew of grape, coffee rust, and South American leaf blight of rubber trees. In each epidemic, people played an important role in promoting or slowing the development of the disease. Using these four diseases as examples, describe two ways in which people’s actions enhanced the development of plant disease epidemics and two ways in which people attempted to slow or stop these epidemics. Please use a different disease for each example.
2) The Effectiveness of Quarantines
Quarantines have been used in the management of both coffee rust and South American leaf blight of rubber trees. While each disease was present on its host plant growing in its native habitats, neither disease caused major problems until the plant was brought under cultivation. Describe at least two differences between the natural and plantation systems that affect the development of disease epidemics. Also discuss why the two epidemics were more severe when the plants were grown in the plantation systems.
3)Monoculture and Plant Disease Epidemics
You have now learned about several plant diseases (including late blight of potato, downy mildew of grape, coffee rust, and South American leaf blight of rubber) in which the practice of monoculture played a significant role in the development of an epidemic. Define the term monoculture, and describe at least one advantage and one disadvantage of using the practice. Use one of the disease systems you have learned about as an example.
4) Quarantines for Plant Disease Management
The overall goal of plant pathologists is to manage plant diseases. So far, you have learned about a number of disease management strategies, including sanitation, eradication, host resistance, and pesticide use. Now, you have been introduced to the concept of managing plant diseases through the use of quarantines. Describe two attributes of a plant disease that might allow for the successful use of quarantines as a management strategy. Also, give an example of a plant disease that has been successfully managed through the use of quarantines and an example of a plant disease that is unlikely to be managed with quarantines.