tar spot

noun

A fungal disease affecting various plants and causing dark spots on leaves.

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Meanings

nountar spot (uncountable)
  1. uncountableA fungal disease affecting various plants and causing dark spots on leaves.

    Tar spot is a relatively minor disease in the Americas, but it is very common and often is present on 50% of the leaves in a grove.

    2003, Randy C. Ploetz, Diseases of Tropical Fruit Crops, page 47
    2 more examples

    Species of Phyllachora cause diseases in plants known as leaf tar spots. P. maydis, responsible tor the maize tar spot, is one of the few species that can cause severe leaf damage.

    1990, R. S. Mehrotra, An Introduction to Mycology, page 335

    Large and small tar spot are apparently more abundant in the eastem and westem United States, respectively. […] Premature defoliation can occur if tar spot is severe.

    1996, F. H. Tainter, Principles of Forest Pathology, page 459
Cite this entry
APA

tar spot. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/tar%20spot

MLA

“tar spot.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/tar%20spot. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “tar spot,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/tar%20spot.

Source: tar spot on Wiktionary, CC BY-SA 4.0.