Evolution and Pest Management

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.