Chapter 18 - Conserving epiphytic microorganisms on fruits and vegetables for biological control

Abstract

In the chapter, a broad definition of biological control is used to discuss biological control systems on the surfaces of fruits and vegetables. This definition involves not only "one-on-one" relationships between antagonists and pathogens but also host-mediated resistance responses of the host and naturally occurring and induced antimicrobial chemicals. It explores the instances where natural suppressive microbial populations may occur on the surface of fruits and vegetables, which affect disease development. Biological control of plant diseases does not occur in a vacuum. It is a dynamic process involving the microecology of the pathogen and antagonists as well as resistance responses of the host. There is growing evidence that some epiphytic populations on the surfaces of fruits and vegetables are not there incidentally but may be under the genetic control of the host as part of its defense. Nutrient competition is an important means by which epiphytic antagonists suppress plant pathogens. Plants also have the capability to "control" microbial populations through the excretion of constitutive and induced antimicrobial compounds. Such compounds differentially favor "suppressive populations" of antagonists over other saprophytes or pathogens. The ability of plants to signal and attract specific predaceous "bodyguards" against insect attack demonstrates how plants can influence external biological control agents in response to specific pests.