Plant Diseases

Abstract

The biological control of plant diseases is based on the use of microorganisms that act directly or indirectly against the pathogen. There has been an increasing demand for biocontrol-based strategies of plant disease management; and, for all plant niches, there have been reports on microbial species that play a role in biocontrol. Some species are commercially available to growers worldwide to prevent the disease onset. For the biocontrol of plant diseases, microorganisms act as parasites of the pathogens’ resting structures, such as sclerotia of Sclerotiania sclerotiorum and eggs and/or juveniles of nematodes Meloidogyne spp. Other microorganisms produce antibiotic compounds that protect the plant tissue, such as the plant growth-promoting rhizobacteria that colonize plant roots and release antibiotics that tackle damping-off-causing pathogens. Some agents consume free nutrients on the plant and scavenge them from the pathogen; for instance, some yeasts protect fruits from postharvest infection caused by Botrytis cinerea. Upon colonization of the plant tissue, receptors from the cell membrane perceive the microbial colonization and trigger an induced resistance that result in broad-spectrum plant protection. Actually, most of the largely used biocontrol strategies combine more than one mode of action, and rarely they have been reported as exercising a selection pressure; in other words, they ensure durable and reliable plant protection against diseases. In this chapter, we address the concepts of biological control of plant diseases, the most important microorganisms with such role, and the strategies growers can follow to adopt integrated crop management.

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