A biologist specializing in mycology is called a mycologist.
Mycology branches into the field of phytopathology, the study of plant diseases, and the two disciplines remain closely related because the vast majority of plant pathogens are fungi.
Historically, mycology was a branch of botany because, although fungi are evolutionarily more closely related to animals than to plants, this was not recognized until a few decades ago. Pioneer mycologists included Elias Magnus Fries, Christian Hendrik Persoon, Anton de Bary, and Lewis David von Schweinitz.
Many fungi produce toxins, antibiotics, and other secondary metabolites. For example, the cosmopolitan (worldwide) genus Fusarium and their toxins associated with fatal outbreaks of alimentary toxic aleukia in humans were extensively studied by Abraham Joffe.
Fungi are fundamental for life on earth in their roles as symbionts, e.g. in the form of mycorrhizae, insect symbionts, and lichens. Many fungi are able to break down complex organic biomolecules such as lignin, the more durable component of wood, and pollutants such as xenobiotics, petroleum, and polycyclic aromatic hydrocarbons. By decomposing these molecules, fungi play a critical role in the global carbon cycle.
Fungi and other organisms traditionally recognized as fungi, such as oomycetes and myxomycetes (slime molds), often are economically and socially important, as some cause diseases of animals (such as histoplasmosis) as well as plants (such as Dutch elm disease and Rice blast).
Apart from pathogenic fungi, many fungal species are very important in controlling the plant diseases caused by different pathogens. For example, species of the filamentous fungal genus Trichoderma considered as one of the most important biological control agents as an alternative to chemical based products for effective crop diseases management.