The crops we eat are constantly at risk of harm from pests. But what are these pests? In this activity, students will develop a definition of an agricultural pest that is meaningful to them and identify categories of pests such as insects, rodents, mollusks, weeds, and diseases.

• Pictures of pests that affect our food crops.
  • Pests should include insects, mites, weeds, and, if possible, diseases. See Agricultural Pests, Natural Enemies Gallery, USDA Image Gallery, or Virginia Tech Weed Identification Guide.
  • Pictures can be printed, or compiled on PowerPoint slides.
• Pictures of beneficial organisms similar to the pests you chose.
• Internet access
• Agricultural Pests worksheet, 1 copy per student
• Credible Source Guide, 1 copy per student
• Background Information for teacher reference

1. Divide students into small groups and give each group a copy of the Agricultural Pests worksheet.
2. As a class, create a preliminary definition of an “agricultural pest.” To begin creating the definition, have students brainstorm in their groups examples of organisms they think might be pests. They should take notes and make changes in their definition as they discuss options with their group.
3. Have students look through the set of agriculture-related pest pictures provided for each group.
4. Instruct students to complete the data table as they review their pictures. If needed, have students research the organisms online to learn if they are pests or beneficial and why they belong in this category. Students should also use the Credible Source Guide as they perform their research. Select a “Fact Checker” for each group.
5. When students complete their data tables, each group should present their findings, and a Fact Checker from another group should verify accuracy.
6. Provide names of a few organisms to research if students were unable to fill their table.
7. When students have completed their data table, watch the two videos about agricultural pests. The first video shows how plants can defend themselves and which pests might affect the plants. As students watch each video, have them record the names of the different pests. The Amazing Way Plants Defend Themselves 
8. Next, watch Do We Really Need Pesticides? 
9. After students have viewed both videos, discuss the various pests shown in the video. If pictures of fungal and bacterial pests were not used at the beginning of this activity, look at some pictures of the effects of these organisms. Most of them are microscopic and cannot be directly observed—what we observe are the effects of the organism living in or on the plant. 
10. Have students review their notes and worksheet to create a final working definition of an "agricultural pest." The definition should be similar to: An organism living and growing where it is not wanted and can cause damage to crops that are grown for food.

Summary:

We rely on crops grown on farms to supply us with the food we need to sustain a healthy life. To ensure that these crops are grown successfully, farmers must manage the pests that feed on or harm the crops. There are several methods of pest control in farming; the use of pesticides is one method that farmers use to to control pests. There is a wide variety of pesticides and each type targets a certain type of pest. Insecticides target insects; fungicides target fungi; and herbicides target weeds. In addition to pesticides, there are many other methods farmers use to control pests.

Optional Extension Activities:

• Assign an Agricultural Pest Research Project. Use the Poster/Infographic Rubric and Credible Source Guide.
• Research the pest that causes citrus greening disease. Review background information and use the Citrus Greening Disease worksheet as a guide.

This activity is part of the Science and Our Food Supply: Exploring Food Agriculture and Biotechnology (2020) curriculum. Find more classroom activities for middle and high school on the Matrix.