[Tech Talk] Where Do Pests Come From?

Columns - Technically Speaking

Although pests seemingly come from nowhere, there is rhyme and reason to where and when they appear. Contrary to what some early thinkers believed, the answer is simple.

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August 31, 2012

Pest management in the 21st century is based on the premise that unwanted organisms can be excluded or eliminated from our living and working spaces. Pests, like all living organisms, require food, water and shelter to survive. Remove those conditions, and you are one step closer to living in a pest-free environment.

In its simplest form, a pest is anything that reduces the availability, quality or value of human resources — and that includes health. Because the idea of a pest is subject to interpretation, it is possible for the same organism to be a nuisance in one context and advantageous in another. Take the ladybug, for example: it can be an unwanted overwintering pest inside buildings during colder months, or a beneficial predator in agricultural food crops.


A Recipe for Pests? Early attempts to understand pest origins stemmed from the idea of spontaneous generation. The prevailing belief for nearly 2,000 years, spontaneous generation suggested pests were created by unsanitary conditions. One proponent, Jan Baptist van Helmont, went so far as to provide recipes for pests. His notes indicate his belief that a piece of soiled cloth mixed with wheat would produce a mouse in 10 days, and rotting meat created maggots.

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To disprove spontaneous generation, Italian physician and naturalist Francesco Redi performed experiments in the 17th century to show that meat was not, in fact, the source of maggots. In his experiments, meat left in open containers was soon infested with maggots, where meat in gauze-covered jars was not infested. Redi’s experiments demonstrated that flies were responsible for the appearance of maggots on rotting meat, and that these “pests” were naturally occurring organisms. By excluding flies, Redi prevented infestation.


A Simple Answer. So where do pests come from? The answer, simply, is nature. The organisms we consider pests are naturally occurring species that live and survive in our world. Each species has its own role or function within the ecosystem and interacts with other living and non-living components of the environment. Organisms are adapted to exploit resources in a way that reduces competition with other, similar species.

An interesting example of this phenomenon is the common bed bug, an organism that prefers to feed on human hosts. Evidence suggests that this insect shared a common ancestor with the bat bug, which as its name suggests, feeds on bats. By switching to a new host, the bed bug no longer had to compete for food with bat bugs, making it an important and reviled pest today.

Other pests, however, can be pre-adapted to exploit human conditions. Insects that feed on dried plant material, for example, are well equipped to survive in crop debris, grain silos, production plants, grocery stores and our homes. In this way, humans make food acquisition for these pests much easier than finding scattered seeds on the forest floor. An abundant and predictable food source is one reason our environments are attractive targets for pest species.


Solving the Problem. Recognizing that pests are natural living organisms with specific but unique requirements means that professionals can apply this information to provide a more targeted approach to pest control. Informing customers about pest biology will reinforce important Integrated Pest Management practices of exclusion and source elimination as well. Clients may be more willing to comply with sanitation and structural repairs if they see the direct link to pest issues. Ultimately, educating clients about pest origins offers professionals the leverage needed to implement effective and successful strategies.



Matt Frye is the staff entomologist at JP McHale Pest Management in Buchanan, N.Y. He is a member of the Entomological Society of America and the Copesan Technical Committee and can be reached at mfrye@giemedia.com.

Copesan is an alliance of pest management companies with locations throughout North America. To learn more, visit www.copesan.com.