Pesticides as Chemical Tools in IPM: A Lesson Plan

Article

Title: Pesticides as Chemical Tools in IPM

Author: Carol Pilcher

Organization: Iowa State University

Topic: Chemistry

Grade Level: 10

Time frame: Two 50-minute periods

Overview: This module is designed to assist students with understanding the importance of pesticides as chemical tools. The chemistry of a pesticide is important for understanding the composition of the product, the classification of pesticides according to their use and the classification of insecticides according to their chemical makeup. This knowledge of pesticides can assist students with understanding what pesticides are currently being used around their home, neighborhoods, and school.

Purpose: After completion of this module, the student will be able to

  • Understand a pesticide label, especially the trade name, common name, and chemical name.
  • Identify the general classification of pesticides by understanding what they control.
  • Identify the classification of insecticides by understanding the chemical makeup.
  • Identify pesticides that are currently being used around the home and understand how to classify these chemicals.

 

Materials:

  • The Pesticide Label” worksheet
  • “Pesticides Used Around Your Home” worksheet

 

Getting Ready: The teacher will review the technical information section on pesticides. In addition, the teacher will need to identify a location for Internet access for student activities. Verify access to Internet sites listed in Activities Section and the Internet Resources Section.

Motivate (Engage): To introduce this activity the teacher should discuss with the students how there are a number of types of chemical products a person can buy when they go to the store. The use of chemicals has helped mankind and the environment in many ways. Have the students guess why chemicals are important (writing these on the board can help in this brainstorming activity). Students may answer preservation of food, medicine, plastics, rubber, clothing, preservation of wood (houses, fences, decks, etc.), and protection of crops, animals and people from pests. Students should think of reasons how chemicals could be harmful. This will lead into a discussion on how chemical use must be guided by safety, understanding of proper uses, and careful planning.

Activity (Explore):

  1. Explain what a pesticide is and the importance of chemistry in pesticides.
  2. Explain the parts of a pesticide label. Focus on the trade name, common name, chemical name, and chemical formula.
  3. Have each student complete “The Pesticide Label” exercise.
  4. Explain the classification of pesticides.
  5. Explain the classification of insecticides according to their chemical makeup.

 

Safety Tips: Pesticides are chemicals that could be dangerous to humans. Have the students wash their hands after touching any pesticide containers in the class and after completing the Going Further activity.

Going Further (Extensions): Have the students take home the “Pesticides Used Around Your Home” worksheet. This will help students realize how every home has one or more pesticides stored there. If a student goes to a hardware store or a lawn & garden center, they will experience the great variety and quantity of pesticides available to the general citizen. Have the students bring their findings to class the next day.

An interactive web site that allows students to explore a typical house for pesticides is available at: http://www.epa.gov/opptintr/kids/hometour/index.htm

Closure: Summarize this activity by discussing what pesticides the students discovered in their home or garden center explorations. Ask them about their impressions of the variety of chemicals which are classified as pesticides.

Assessment (Evaluation): This activity could easily lend itself to a formal written evaluation of concepts learned. It is suggested that the teacher obtain Xerox copies of a pesticide label (via the Internet) and ask students questions about the specific label.

Resources:
Published books --

Pedigo LP. 1999. Entomology and pest management. 3rd Ed. Upper Saddle River, NJ: Prentice Hall. 691 p.

Ware GW. 1994. The pesticide book. 4th Ed. Fresno, CA: Thomson Publications. 386 p.

Internet web sites --
Environmental Protection Agency

Interactive Label

Learn About Chemicals Around Your House

Technical Information: A pesticide is any chemical used to prevent, destroy, or repel pests. Pests can be insects, weeds, diseases, or mice and other rodents. According to the most recent U.S. EPA Pesticide Industry Sales and Usage Report, 1.23 billion pounds active ingredient of conventional and other pesticide chemicals were applied in the U.S. in 1997 (Aspelin and Grube, 1999). Furthermore, 77% (or 944 million pounds) of the chemicals were designated specifically for agricultural use (Aspelin and Grube, 1999). When considering all the chemical elements in the periodic table, only 22 of the 106 elements are used for pesticides (Ware 1994). Some of these elements include carbon, chlorine, arsenic, mercury, and zinc. Furthermore, almost all pesticides contain carbon so they are organic compounds. Those pesticides that do not contain carbon are called inorganic compounds.

Pesticide Label: A pesticide label must follow guidelines established by the federal government. The following are important components of any pesticide label. The trade name is the name used in advertising. It is printed on the front panel of the label and is the easily identified. The chemical name is a description of the chemical structure of the product. Often times the chemical name is very complicated because it must follow the rules of nomenclature for organic chemistry. As a result, the common name is a simplified version of the chemical name and makes it easier to identify the product.

Classification of Pesticides: Pesticides can be grouped according to the pests that they control. Some examples include:

  • Algicides - Chemicals used to manage algae in areas such as swimming pools.
  • Avicides- Chemicals used to manage birds.
  • Disinfectants- Chemicals used to destroy harmful microorganisms.
  • Fungicides- Chemicals used to manage fungi.
  • Herbicides- Chemicals used to manage unwanted plants or weeds.
  • Insecticides- Chemicals used to manage insects and other related creatures, such as ticks, spiders, and centipedes.
  • Microbial Insecticides- Naturally occurring insect-disease microorganisms that are lethal to a specific group of insects.
  • Molluscicides- Chemicals used to control snails or slugs.
  • Pheromones- Chemicals used to attract insects.
  • Repellents- Chemicals used to repel insects or other pests.
  • Rodenticides- Chemicals used to manage rats, mice, and other rodents.

 

Classification of Insecticides: Insecticides may be further classified according to their chemical makeup. These insecticides are generally classified as organophosphates, carbamates, and pyrethroids.

  • Organophosphate insecticides were developed during World War II (Pedigo 1999). These insecticides are named because they contain phosphorous and are derived from phosphoric acid (Ware, 1994). They are some of the most toxic insecticides.
  • Carbamates were developed in 1951 (Pedigo, 1999). These insecticides are named because they are derived from carbamic acid (Ware, 1994). They have low human oral and dermal toxicity (Ware, 1994). However, they are very toxic to Hymenoptera, including bees.
  • The natural insecticide pyrethrum was commercially available in 1949. Pesticide chemists developed synthetic formulas (called pyrethroids) for the marketplace.

 


Pesticide Label

  1. Find the Environmental Protection Agency Website.
    1. What is the URL for this site:
       
  2. Browse the EPA Topics. Select the pesticide topic, select the pesticide legal aspects section, select the labeling section, and then select the read the label first section.
    1. Review the interactive label exercise. What additional information is included on the label (besides the common name, trade name, and chemical name)?




       
  3. Try to find a pesticide label posted on the Internet.
    1. What is the URL for this site:
       
    2. What is the product name:
       
    3. What is the common name:
       
    4. What is the chemical name:
       

Pesticides Used Around The Home

  1. Search around your home, neighborhood and school for pesticides. If you cannot find three pesticides, visit the lawn and garden center of your local hardware store.
     
  2. Be Careful!! These products are useful for managing pests, but some of the chemicals may be dangerous to humans. They may irritate your skin, eyes, nose, and throat. They may be POISONOUS.
     
  3. Identify at least 3 pesticides you find.
    1.  
    2.  
    3.  

     

  4. Using the handout “Classification of Some Common Pesticides According to General Use” classify pesticides according to their general use.
    1.  
    2.  
    3.  
  5. Are any of the pesticides classified as insecticides? If so, determine if they are organophosphates, carbamates, or pyrethroids
    1.  
    2.  
    3.  
  6. Now check your cabinets for chemicals used for cleaning and disinfecting surfaces. Do any of the chemicals have an EPA Registration Number? Identify at least 3 products that you find. These too are pesticides!
    1.  
    2.  
    3.  

Classification of Some Common Pesticides According to General Use

 

Pesticide General Uses
Algicides Chemicals used to manage algae in areas such as swimming pools.
Avicides Chemicals used to manage birds.
Disinfectants Chemicals used to destroy harmful microorganisms.
Fungicides Chemicals used to manage fungi.
Herbicides Chemicals used to manage unwanted plants or weeds.
Insecticides Chemicals used to manage insects and other related creatures, such as ticks, spiders, and centipedes.
Microbial Insecticides Naturally occurring insect-disease microorganisms that are lethal to a specific group of insects.
Molluscicides Chemicals used to control snails or slugs.
Pheromones Chemicals used to attract insects.
Repellents Chemicals used to repel insects or other pests.
Rodenticides Chemicals used to manage rats, mice, and other rodents.

 

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