mildew, name for certain fungi and protists, for the diseases they cause in various crops, and for the discoloration (and sometimes the weakening and disintegration) they cause in such materials as leather, fabrics, and paper. The powdery mildews usually grow on the surface of plant tissues, forming a gray or white coating and absorbing nourishment from the host. Although traditionally considered fungi, the downy mildews are now more often considered protists. They attack grapes, cucumbers, potatoes, and other vegetables. Methods of making fabrics and leather resistant to mildew have been devised. For the occurrence and control of mildews in agriculture, see diseases of plants. Powdery mildews are classified in the kingdom Fungi, phylum (division) Ascomycota; downy mildews are classified in the kingdom Protista, phylum (division) Oomycota.

Conspicuous mass of threadlike hyphae (see mycelium) and fruiting structures produced by various fungi (kingdom Fungi; see fungus). Mildew grows on cloth, fibres, leather goods, and plants, using these substances as food for growth and reproduction. Downy mildew and powdery mildew are plant diseases that affect hundreds of species.

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Mildew refers to certain kinds of mold or fungus. In Old English, it meant honeydew (a substance secreted by aphids on leaves, formerly thought to distill from the air like dew), and later came to mean mildew in the modern senses.

• The term mildew is often used generically to refer to mold growth, usually with a flat growth habit. Molds can thrive on any organic matter, including clothing, leather, paper, and the ceilings, walls and floors of homes with moisture management problems. Mildew often lives on shower walls, windowsills, and other places where moisture levels are high. There are many species of molds. In unaired places, such as basements, they can produce a strong musty odor.
• What most horticulturalists and gardeners call mildew is more precisely called powdery mildew. It is caused by many different species of fungi in the order Erysiphales. Most species are specific to a narrow range of hosts, and all are obligate parasites of flowering plants. The species that affects roses is Sphaerotheca pannosa var. rosa.
• Another plant-associated type of mildew is downy mildew. Downy mildews are caused by fungus-like organisms in the family Peronosporaceae (Oomycota). They are obligate plant pathogens, and the many species are each parasitic on a narrow range of hosts. In agriculture, downy mildews are a particular problem for growers of potatoes, grapes, tobacco and cucurbits.

The English word was exported into French as mildiou and as mildiu in Spanish.

See also

• Phase I Environmental Site Assessment

References

External links

• How to Prevent and Remove Mildew in Relation to the House and Household Furnishings from Virginia Tech and Virginia State University
• SAFECROP - Proceedings of the 5th International Workshop on Grapevine Downy and Powdery Mildew