Evolution and Pest Management

by

Norman Johnson

• LAST REVIEWED: 26 October 2023
• LAST MODIFIED: 26 October 2023
• DOI: 10.1093/obo/9780199941728-0151

Introduction

Because they cannot easily flee from natural enemies, plants are particularly prone to threats from other organisms including pathogens and animal herbivores. Moreover, plants often face intense competition for resources (including space) from other plants. When referring to agricultural plants and other plants of human concern, these pathogens, herbivores, and other competing plants (weeds) are collectively known as pests. Pest management encompasses human activities that limit the damage from pests to preferred plants. Managing pests is particularly critical to agriculture as losses from pests can cause substantial loss of crops, especially in areas of food insecurity and fast-growing human populations. Because of space limitations, this entry focuses on the management of insect and microbial pests that threaten agricultural plants; however, similar principles apply to forest pests and urban pests as well as to weeds. Pest management is an applied science that relies heavily on concepts, principles, and information from ecology, genetics, and evolutionary biology. Evolutionary principles help identify current pests and help biologist predict which organisms are likely to become pests. Evolutionary biology also influences pest management strategies. Chemical agents (pesticides) can be effective in managing or even eliminating pests, at least for a while, but nfortunately, pests can evolve resistance to those pesticides. Understanding how pests evolve resistance can help in the development of practices aimed at slowing the evolution of resistance. Guidance from evolutionary biology also assists in the best use of a plant’s natural defenses and use of biological control agents in pest management. Pest management benefits from information about the genetic basis of traits of the host plant and or their pests. For instance, knowing that a gene affects an insect pest’s resistance to a specific pesticide can help to thwart the evolution of resistance in that insect or to develop new insecticides. In recent years, DNA markers have increasingly been used to find genes that likely contribute to specific phenotypes of interest and regions of the genome that have been impacted by selection. Development of these tools rest on a foundation of evolutionary genetics.

General Resources

Pest management is one of several important applications of evolutionary biology to practical matters that range from agriculture to medicine to conservation to law. Johnson 2022 is a recent book-length treatment of evolutionary applications. One salient conclusion is that ideas from one application of evolutionary biology can sometimes be applied to others. For instance, pest management treatments and strategies to treat bacterial infections in humans both are affected by the nature of resistance of the organisms being targeted and the extent of the cost of being resistant (Johnson 2022). Pest management is especially critical to agriculture as losses from pests and pathogens alone markedly reduce the yield of crops. Savary, et al. 2019 estimates such losses to be roughly a quarter to a third for each of the five major food crops: wheat, rice, maize, potato, and soybean. These losses are not evenly distributed across the world; in fact, the greatest losses are in areas of food insecurity and fast-growing human populations. One reason for why agricultural pests can cause so much damage to crops is that the crops humans rely on usually have a dearth of genetic variation. Dunn 2017 provides a book-length treatment of the consequences of this depleted genetic variation in crops. In recent years, pest management has relied increasingly on genetically modified organisms. Lynas 2018 chronicles history of the use of genetic modifications in managing insect pests and weeds. Evolutionary biology is a broad discipline with diverse aspects, many of which are relevant to pest management. The textbook Futuyma and Kirkpatrick 2017 presents a broad, general overview of evolutionary biology. Detailed information about tools of molecular evolution and how evolutionary biologists use them to make inferences about how evolutionary processes are operating in natural populations can be found in Hahn 2018. Walsh and Lynch 2018 provides a comprehensive treatment of the tools and techniques used in population and quantitative genetics.

• Dunn, R. 2017. Never out of season: How having the food we want when we want it threatens our food supply and our future. New York: Little, Brown and Company.

  Discusses many of the failures of pest management (and some of the successes). Provides a wealth of examples about how the loss of genetic diversity in crops puts these crops at risk of devastation from pests. Also points to some practical solutions to help mitigate such risk.

• Futuyma, D. J., and M. Kirkpatrick. 2017. Evolution. 4th ed. Oxford: Oxford Univ. Press.

  This leading textbook on evolution covers the general principles of the field including natural selection and other evolutionary processes as well as phylogenetic methods.

• Hahn, M. W. 2018. Molecular population genetics. New York: Oxford Univ. Press.

  This recent book covers molecular genetic tools and methods used in population genetics. It contains much information about tests for detecting selection and other evolutionary processes.

• Johnson, N. A. 2022. Darwin’s reach: 21st century applications of evolutionary biology. Boca Raton, FL: CRC Press.

  This recent book summarizes general applications of evolutionary biology. Chapters 8 and 9 directly pertain to pest management. Also highlights parallels across different evolutionary applications. For instance, adaptative therapy in cancer treatments borrows from concepts applied in integrated pest management. Additionally shows that costs of evolving resistance are important in several applications, including pest management.

• Lynas, M. 2018. Seeds of science: Why we got it so wrong on GMOs. London: Bloomsbury.

  Written by a former GMO opponent turned cautious defender of the practice, this book presents a nuanced history of GMOs used in agriculture settings. Describes several successes of genetic modification improving crops, including making them more resistant against disease.

• Savary, S., L. Willocquet, S. J. Pethybridge, P. Esker, N. McRoberts, and A. Nelson. 2019. The global burden of pathogens and pests on major crops. Nature Ecology & Evolution 3:430–439.

  DOI: 10.1038/s41559-018-0793-y

  Using a survey of experts, this paper estimates the extent of the damage pests and pathogens cause to the five main food crops. Rice is affected most by pathogens and pests, with an estimated average loss of 30 percent. For the other four crops, the losses are roughly a fifth. Also includes a list of the pathogens and pests that cause the greatest losses.

• Walsh, J. B., and M. Lynch. 2018. Evolution and selection of quantitative traits. Oxford: Oxford Univ. Press.

  DOI: 10.1093/oso/9780198830870.001.0001

  This extraordinarily detailed and comprehensive reference book presents the population genetic foundations of quantitative genetics. Among other things, it covers tests for detecting selection from both population genetic and quantitative genetic data, the mechanics of family and group selection, and how quantitative genetic variation is maintained. This book is mainly for experts in the field.