pyrethrum

noun

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py·re·thrum | \ pī-ˈrē-thrəm

, -ˈre-

Definition of pyrethrum

1 : any of several chrysanthemums with finely divided often aromatic leaves including ornamentals as well as important sources of insecticides

2 : an insecticide made from the dried heads of any of several Old World chrysanthemums (especially Chrysanthemum cinerariaefolium)

Examples of pyrethrum in a Sentence

Recent Examples on the Web During the 1980s, the pyrethrum crisis began, instigated by the chemical synthesis of pyrethroids that led to the manufacturing of cheaper but non-organic products. — Cecilia Rodriguez, Forbes, 4 Mar. 2021 The pyrethrum is known as the ‘flower of death’ – a nickname that neatly describes this delicate daisy imbued with murderous power. — Cecilia Rodriguez, Forbes, 4 Mar. 2021 The pyrethrum is cultivated mainly in the hills of Nakuru in Kenya and is the arch foe of the insect world. — Cecilia Rodriguez, Forbes, 4 Mar. 2021 Look for pyrethrum in the list of ingredients on your bug spray; it’s one of the most popular ingredients in natural insect repellents. — Andrea Beck, Better Homes & Gardens, 21 Aug. 2020 Some gardeners mention pyrethrum as an option for the nymphs, but for the adults, malathion and Sevin are the effective options. — Calvin Finch, ExpressNews.com, 21 June 2019 Nymphs can be controlled with insecticidal soap, pyrethrum, rotenone or neem. — Ellen Nibali, baltimoresun.com, 11 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pyrethrum.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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Last Updated

26 May 2021

Cite this Entry

“Pyrethrum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pyrethrum. Accessed 20 Jun. 2021.

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More Definitions for pyrethrum

pyrethrum

noun

py·re·thrum | \ pī-ˈrē-thrəm

, -ˈreth-rəm

Medical Definition of pyrethrum

1 : any of several chrysanthemums with finely divided often aromatic leaves including ornamentals as well as important sources of insecticides

2 : an insecticide consisting of or derived from the dried heads of any of several Old World chrysanthemums (genus Chrysanthemum of the family Compositae)