Major Plant Diseases Caused by Phoma sensu lato Species and Their Integrated Management Strategies

Phoma is taxonomically a complex genus, and most species have been reported as pathogens of different organisms, from plants to animals and even human beings. Some of the Phoma species are considered as being the most devastating plant pathogens worldwide. The phytopathogenic species can attack a wide range of plants including crops, ornamentals, and native species from various families. They also inhabit different parts of plants, from leaves to roots. Phoma species induce a range of symptoms, such as leaf and stem spot, leaf blotch, stem blight, stem canker, shoot necrosis, root and crown rot, vascular disorders, fruit ripening, and even pre-emergence seedling damping-off. As cosmopolitan plant pathogens, Phoma species may cause serious yield losses in agriculture and horticulture and are a threat to natural ecosystems. Phoma disease management has always been problematic to plant pathologists. Although some disease management practices, such as the application of resistant cultivars, chemical control, and in some rare cases, the use of biological control agents, have been proposed in the literature, the best control strategy is adopting an integrated disease management approach. In this chapter, the most important diseases caused by Phoma species in economically significant plants are discussed. In each section, the causal agent of each disease, hosts, symptoms, disease development, and management strategies, with an emphasis on non-chemical disease management strategies, are reviewed.