Also called pyrethrin I. a viscous, water-insoluble liquid, C21H28O3, extracted from pyrethrum flowers, used as an insecticide.
Also called pyrethrin II. a like compound, C22H28O5, obtained and used similarly.
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How to use pyrethrin in a sentence
Although each product has the same effect on insects — and presents the same risks to beneficial insects — pyrethrin usually is more potent and lasts longer.Many companies advertise ‘green’ pest control. But is it possible? And does it work? | Kevin Brasler | Washington Consumers' Checkbook | April 8, 2021 | Washington Post
British Dictionary definitions for pyrethrin
Also called: pyrethrin I an oily water-insoluble compound used as an insecticide. Formula: C 21 H 28 O 3
Also called: pyrethrin II a compound of similar chemical structure and action, also found in pyrethrum. Formula: C 22 H 28 O 5
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012