witches'-broom

witches'-broom
/wich"iz broohm', -broom'/, n. Plant Pathol.
an abnormal, brushlike growth of small thin branches on woody plants, caused esp. by fungi, viruses, and mistletoes.
[1865-70]

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 symptom of plant disease that occurs as an abnormal brushlike cluster of dwarfed, weak shoots arising at or near the same point; twigs and branches of woody plants may die back. There are numerous causes, including rust (Gymnosporangium and Pucciniastrum); Apiosporina, Exobasidium, and Taphrina fungi; mites; insects; viruses; mycoplasmas; bacteria; and mistletoes. Susceptible plants include alder, alfalfa, Amelanchier, birch, California buckeye, Chamaecyparis, cherry, cherry laurel, elm, fir, hackberry, Holodiscus (ocean spray), honey locust, juniper and red-cedar, manzanita, mountain heath, mulberry, oak, potato, rhododendron, rose, sophora, spruce, and strawberry.

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Universalium. 2010.

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Look at other dictionaries:

  • witches'broom — n. An abnormal brushlike growth of weak, closely clustered shoots or branches on a tree, such as the hackberry, caused by fungi or viruses. * * * …   Universalium

  • witches'-broom — [wich′iz bro͞om′] n. an abnormal growth of closely bunched, slender twigs at the ends of branches of various woody plants, caused by fungi, viruses, etc …   English World dictionary

  • witches'-broom — | ̷ ̷ ̷ ̷| ̷ ̷ noun or witch broom : an abnormal tufted growth of small branches on a tree or shrub caused by fungi, viruses, mistletoes, insect injury, or physiological disturbances called also hexenbesen, staghead * * * /wich iz broohm , broom… …   Useful english dictionary

  • witches'-broom — witch′es broom n. ppa an abnormal, brushlike growth of small, thin branches on woody plants, caused esp. by fungi and viruses • Etymology: 1865–70 …   From formal English to slang

  • witches' broom — /ˈwɪtʃəz brum/ (say wichuhz broohm) noun a dense mass of small thin branches frequently emerging from a swelling on a tree branch, as on cherry (caused by fungus of the genus Taphrina) and on conifers (caused by various mistletoes). Also, witches …  

  • witches' broom — noun an abnormal tufted growth of small branches on a tree or shrub caused by fungi or insects or other physiological disturbance • Syn: ↑witch broom, ↑hexenbesen, ↑staghead • Hypernyms: ↑tuft, ↑tussock …   Useful english dictionary

  • witches'-broom — noun Date: 1881 an abnormal tufted growth of small branches on a tree or shrub caused especially by parasitic organisms (as fungi, viruses, or aphids) …   New Collegiate Dictionary

  • witches' broom — noun dense twiggy growth in a tree caused by infection with fungus (especially rusts), mites, or viruses …   English new terms dictionary

  • Lilac witches’-broom — (LWB) is a disease of lilacs caused by the Phytoplasma Candidatus Phytoplasma fraxini . This phytoplasma was first identified as the causal agent of Ash Yellows and has since been attributed to both diseases.Symptoms of the LWB phytoplasma… …   Wikipedia

  • witches'-besom — /wich iz bee zeuhm/, n. Plant Pathol. witches broom. [1865 70] * * * …   Universalium

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