Epidemiology and management of fungal diseases in dry environments

Fungal pathogens are among the most damaging biotic factors for plants. More than 10,000 fungal species attack plant roots, stems, leaves, flowers, seeds or fruits, and cause diseases that vary in their severity and economic impact. In contrast, many fungal species act as biocontrol agents, producers of antibiotics, promoters of plant growth and development, and decomposers of waste material. Fungi occur in temperate, tropical and dry environments. When the conditions are not suitable for fungi, they tend to survive in soil or plant debris as solid structures. Spores of fungal pathogens usually germinate in response to exudates secreted by plants, resulting in hyphal growth towards plants and subsequent infection and disease development. Development of disease epidemics depends on several factors, including aggressiveness of the pathogen, reproduction rate, mode of reproduction, susceptibility of the hosts, and the prevailing environmental conditions. Successful management of fungal diseases depends on how much we understand about the epidemiology of fungal pathogens under certain environmental conditions and cultural practices. This chapter focuses on the epidemiology of fungal pathogens and plant-pathogen interactions in dry environments, and discusses some of the most common fungal diseases in these environments, with a particular focus on wheat root rot, spot blotch and rust diseases.