When Is a Pest an Insect?

Based on materials from Pennsylvania State University, the Pennsylvania Department of Agriculture’s Integrate Pest Management Program and the ‘When Is a Pest’ activity:
Adapted by Rachel Hughes and Kirstin Bittel

Time: 1 class period
Materials: Paper and pencil


Students have just seen the importance of insects as pollinators. Now students are posed with the problem- those insects were nice, but insects are pests right? What to do! Students explore their description of pests and then are asked to question whether spraying with pesticides is always the way to go.

Everyone knows what a pest is, right? Or do they? Whether or not some organism is considered to be a pest depends on the situation, a person's point of view and other "non-scientific" factors.
Consider this statement: If there were no humans on earth, there would be no "pests". Or would there? Differing opinions about pest status often leads to controversy in private and public life about what to do about the "pest problem" at hand. This activity is designed to bring up questions in a group setting and allow the participants to clarify what, when and where a certain organism is or is not a pest and why.

Students will be able to:-
1. articulate that "pest" is a human construct rather than a "natural" category
2. describe the wide range of organisms that can potentially be "pests"
3. identify the different roles a species has besides pestering humans
4. describe how management of a particular species will depend upon a person's perspective

National Science Education Standards
Content Area C- The Interdependence of Organisms
Human beings live within the world’s ecosystems. Increasingly, humans modify ecosystems as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening global stability, and if not addressed, ecosystems will be irreversibly affected.

Resource Websites




As students enter, the word “pest” is written in large letters on the board. Students write what they immediately think of when they see that word and define pest in their own words.

1. Students sit in a group of 4-5, each individual with a piece of paper. Tell students to write at the top:

Not a Pest

2. Explain to them that you want them to each silently spend 5-10 minutes writing down the name of any organism they think might be a pest in the left-hand column. Then they write when or where it is a pest under "Pest" column. If they can think of a situation where or when that SAME organism is NOT a pest, write that down in the far right-hand column. Keep it simple, for e.g.

in the garbage can
Not a Pest
in the woods

3. After the individual students have quietly listed all their pests, have them compare notes within their group by going around the table and have each read their answers. On each pest read aloud, see if the others in the group agree or disagree. Have the first student who reads their answers be the group recorder. This person will add each new species to his or her list as each is mentioned. Note how many times the same organisms were mentioned (e.g. 5 out of 5 students said mosquitoes).

4. Have one student from each group be the reporter and present their group's long list to the class. Have one student write the names of the species on the board as the group's report. If there are points where they cannot reach agreement, have them report back to the class what the different perspectives were.

1. Instruct students to look under the column listing all the organisms. How many times were the same species mentioned? (Ask for a show of hands.) These are likely to be very annoying or harmful species to many people. You can use this list later or over time in the class to build on the concept of pests and develop pest management activities aimed at organisms the students themselves find bothersome.

2. Look at the column containing all the situations in which the organisms were listed as a "Pest". Ask students, “What do these situations have in common?” (Most likely they are all human endeavors of some sort or spoiling something that humans value.)

3. Look at the column deemed "Not a Pest". Ask students, “What do these scenarios have in common?” (Most likely they are a role played by the species in the natural environment and/or their use as food, pleasure or research purposes for humans.)

4. As a class, come up with a class definition of a pest. Encourage them to include some aspect that includes that a pest is a human construct. This definition should be written into their notebooks.

Having agreed upon a definition of pest, ask students what they might do to control them? What do they do to control them in their homes? Invariably cockroaches will come up as a pest. How would they deal with cockroaches if they had a problem with them? The roach motels or insecticide/pesticide spray use will probably be the most common use. For homework ask students to ask family members what their definition of a pest is, provide an example and how would they deal with the pest. They can also search the pest control section of the yellow pages and identify what are the common pests that these companies say they will rid homes of. Why are these animals considered pests? Would the student consider it a pest? Where and when would the animal not be considered a pest? Have students comment on the marketing technique used by the companies. Students should address whether there might be other ways to control these pests.


Embedded Assessment

The homework allows the student to investigate the term pest within their own home. How would they define the term pest now? Is a pest always a pest?



PULSE is a project of the Community Outreach and Education Program of the Southwest Environmental Health Sciences Center and is funded by:

NIH/NCRR award #16260-01A1
The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award


Supported by NIEHS grant # ES06694

1996-2007, The University of Arizona
Last update: November 10, 2009
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