单词	pyrethrum
释义	pyrethrum noun py·​re·​thrum pī-ˈrē-thrəm  -ˈre-  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) Example Sentences Recent Examples on the Web To observe pyrethrum’s effects, Dong and her colleagues attached tiny electrodes to hairs on mosquitoes’ antennae. Rachel Nuwer, Scientific American, 19 July 2021 Do not use pyrethrum products for these or any other pests. Howard Garrett, Dallas News, 26 July 2021 Lives can be spared by applying insect repellents, including a chrysanthemum flower extract called pyrethrum that humans have used for thousands of years. Rachel Nuwer, Scientific American, 19 July 2021 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 See More Word History Etymology Latin, pellitory, from Greek pyrethron, from pyr fire First Known Use circa 1543, in the meaning defined at sense 1 Medical Definition pyrethrum noun py·​re·​thrum pī-ˈrē-thrəm  -ˈreth-rəm  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)
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