Rusts, Smuts And Plant Pathogens

This group gathers Fungi subcategory members that are plant pathogens, fungi whose defining trait is a parasitic relationship with a living crop, tree or other plant host rather than a free-living or symbiotic lifestyle. It spans the rust fungi, named for the orange or reddish powdery lesions they produce on infected leaves, such as coffee rust, which devastated coffee production across historic growing regions and helped shift Sri Lanka's agricultural economy toward tea, and wheat stem rust, a persistent threat to global cereal harvests, alongside tree-killing pathogens such as chestnut blight fungus and Dutch elm disease fungus, both accidentally introduced pathogens that reshaped the forests of Europe and North America by functionally eliminating a once-dominant tree species from much of its range, and Claviceps purpurea, the ergot fungus, whose toxic sclerotia contaminating rye and other grain crops caused historical outbreaks of ergotism in both people and livestock. Every member gathered here causes measurable economic or ecological damage to the plants it infects, a defining trait none of this atlas's other fungus groups share.