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​Chapter 8 Resources​

Chemicals to Protect Plants: Pesticides

Pesticides are a wide variety of chemicals with different target organisms and levels of toxicity. Fungicides are the most common pesticides used to manage plant diseases. Today, scientists are working to reduce the need for fungicides. In fact, most field crops do not receive regular fungicide applications, although many fruit and vegetable crops do. One example is the use of fungicides to manage apple scab. In the United States, pesticide development, application, and residues on food are strictly regulated. Still, the use of pesticides is one of the most controversial aspects of modern agriculture.

• Chapter 8 Podcast

  Chapter 8 Podcast

  Listen to the Podcast (mp3)
  

  The short podcast provided for each chapter includes a review of a major concept or issue, clarification of an important point that can be confusing to students, and questions for students to think about. This podcast defines what pesticides are and discusses their history, as well as some of the risks and benefits associated with their use. In addition, this podcast explains three ways fungicides can be classified.

• Short Writing Assignments

  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) Types of Fungicides I

  The fungicides used to manage some fungal plant diseases can be classified in various ways. Describe two of the three systems commonly used to classify fungicides; include descriptions of the different types of fungicides within each classification system.

  
  

  2)Types of Fungicides II

  Fungicides are commonly used in the production of some crops, such as fruits and vegetables, but not all fungicides are alike. In paragraph form, name and describe two groups of fungicides that differ in what they are made of and two groups of fungicides that differ in how they work.

  
  

  3) Pesticide Facts and Opinions

  You have learned about the issue of pesticides in agriculture, including how they are characterized, how they are regulated, and what benefits and risks are associated with their use. List two important facts that you have learned about agricultural pesticides. Also, indicate whether your new knowledge has changed or reinforced your opinions on the appropriateness of using pesticides for agricultural purposes. Provide specific examples where possible.

  
  
• Longer Writing Assignments

  1) The Risks of Fungicides and Herbal Medicines

  Many people have a negative perception of pesticides, including fungicides. Pesticides are chemicals designed to eradicate unwanted organisms. A fear of chemicals has led some people to believe that pesticides, including fungicides, are dangerous and that their advantages are few. At the same time, many people use herbal supplements to combat everything from the common cold to cancer. Herbal supplements are chemicals, often derived from plants. They are often used without knowledge of their composition and potential risks.

  How are these two groups of chemicals evaluated and regulated? How should they be evaluated and regulated? Should consumers consider the relative risks and benefits of fungicides and herbal medicines before using them? Write a short essay (~ 350 words) on this topic.

  Here are some questions to consider:

  • What is a pesticide? What is a fungicide?
  • What is an herbal medicine or supplement?
  • How are people exposed to fungicides and herbal medicines?
  • How are fungicides and herbal medicines regulated?
  • What kinds of laws regulate the production, sales, and use of herbal supplements? How has this affected their marketing and the public’s perception of them?
  • What are the documented benefits of fungicides and herbal medicines? How effective are they?
  • What are the documented risks of fungicides and herbal medicines? How safe are they?

  
  

  Notes:

  • You can make the audience for the assignment someone other than yourself—for example, a friend or relative who uses herbal medicines. The selection of audience should dictate the style of writing that students use.
  • Opinion papers such as this can be written in several drafts: Draft 1 (evaluated but not graded) summarizes the facts; draft 2 (also evaluated but not graded) incorporates the student’s opinion, supported by the facts; and draft 3 is a polished version of draft 2, which is finally graded. Students appreciate the opportunity to get feedback on their writing and thinking before being assigned a grade. This system also provides an opportunity for students to learn to separate facts from opinions and to evaluate the biases of different sources of information.
  • You can provide students with a reference list (including links), so that this is an exercise in evaluating and using information, rather than finding it. Extra credit can be given for sources with new information that students find and use in their papers.

  
  

  Evaluation of Paper:

  Criteria used in evaluation can include the following:

  • Accuracy and completeness of factual information
  • Development and support of opinion
  • Overall organization and clarity
  • Mechanics (e.g., spelling, grammar, sentence structure)
  • Use of supporting references

  
  

  Important Note: This paper has no “right” or “wrong” conclusion. The student can take either side of the issue (pro–pesticides and/or herbal medicines or anti–pesticides and/or herbal medicines), include the pertinent facts, and use them to support his or her position.

  
  

  2) To Be or Not to Be Organic

  You are the designated grocery store shopper for your apartment. A new organic grocery is opening in your neighborhood, and some of your roommates may be interested in purchasing organic groceries. Since you are a busy and industrious college student, you have only a limited amount of time to go grocery shopping and have already decided that you will purchase all of the apartment’s groceries at one store. Therefore, you and your roommates need to discuss whether you are going to continue buying conventionally grown food or start buying organically grown food.

  In preparation for this discussion, you are doing some research to better understand the food industry. Write a short essay (~ 350 words) in which you present your findings.

  Here are some questions to consider:

  • What does organic mean? What are the U.S. Department of Agriculture (USDA) guidelines for organic crop certification?
  • What are pesticides and mycotoxins?
  • What are the benefits and risks of pesticide use/pesticide avoidance in conventionally and organically grown foods?
  • What are the risks caused by mycotoxins in conventionally and organically grown foods?
  • What are other potential benefits to producers and consumers of organic foods? Consider economic, environmental, health, and social aspects.
  • What are other risks and deterrents to producers and consumers of organic foods? Again, consider economic, environmental, health, and social aspects.

  
  

  Notes:

  • You can make the audience for this assignment the students’ roommates. The selection of audience should dictate the style of writing students use.
  • Opinion papers such as this can be written in several drafts: Draft 1 (evaluated but not graded) summarizes the facts; draft 2 (also evaluated but not graded) incorporates the student’s opinion, supported by the facts; and draft 3 is a polished version of draft 2, which is finally graded. Students appreciate the opportunity to get feedback on their writing and thinking before being assigned a grade. This system also provides an opportunity for students to learn to separate facts from opinions and to evaluate the biases of different sources of information.
  • You can provide students with a reference list (including links), so that this is an exercise in evaluating and using information, rather than finding it. Extra credit can be given for sources with new information that students find and use in their papers.
  • Many topics related to pesticide use are interesting topics for class discussions and student papers. Among them are use of fungicides in developing countries, human testing of pesticides, use of pesticides in urban environments, and development of fungicide-resistant pathogen populations.

  
  

  Evaluation of Paper:

  Criteria used in evaluation can include the following:

  • Accuracy and completeness of factual information
  • Development and support of opinion
  • Overall organization and clarity
  • Mechanics (e.g., spelling, grammar, sentence structure)
  • Use of supporting references

  
  

  Important Note: This paper has no “right” or “wrong” conclusion. The student can take either side of the issue (pro-organic or anti-organic), include the pertinent facts, and use them to support his or her position.