Definition of pyrethrum in English:



  • 1An aromatic plant of the daisy family, typically having feathery foliage and brightly coloured flowers.

    Genus Tanacetum (formerly Chrysanthemum or Pyrethrum), family Compositae: several species, in particular T. coccineum, grown as an ornamental, and T. cinerariifolium, grown as a source of the insecticide pyrethrum

    • ‘Others are synthetic versions of naturally-occurring insecticides, such as those found in the plant pyrethrum.’
    • ‘Some are derived from plants, such as pyrethrum and neem.’
    • ‘Not all herbs smell good - catmint, curry plant, pyrethrum, rue, santolina and tansy are all pretty pongy.’
    • ‘In some areas, extremely fertile soils produce coffee, tea, and pyrethrum (used in making insecticides).’
    • ‘When I looked closely I could see the truck had a PyGanic label with the iconic pyrethrum flower on the side.’
    • ‘This is the area where significant cash crops are grown, including pyrethrum (a flower that produces a natural insecticide), coffee and tea.’
    1. 1.1mass noun An insecticide made from the dried flowers of pyrethrum plants.
      • ‘The spray does not control the adults, so you can either handpick the adults or spray them with pyrethrum insecticide.’
      • ‘By the mid 1800s, the heads of chrysanthemum flowers were used to obtain pyrethrum, and rotenone was extracted from the derris plant.’
      • ‘Rotenone and pyrethrum don't work, even if applied more frequently.’
      • ‘A natural pyrethrum insecticide is cheaper, less harmful and just as effective as those chemical poisons to kill spiders.’
      • ‘Geoff reckons to use a contact spray like pyrethrum which breaks down within about 24 hours.’
      • ‘Daisy plants were first used centuries ago as a lice remedy in the Middle East, and this led to the discovery of pyrethrum insecticides.’
      • ‘Adult mosquitoes were obtained from houses within a village by resting and pyrethrum knockdown collections.’
      • ‘‘That's pyrethrum,’ said Niko ‘it's used as an insecticide.’’
      • ‘Pesticides that are approved for organic farming include copper, sulfur, petroleum distillates, and pyrethrum.’
      • ‘For body lice, use pyrethrum with piperonyl butoxide lotion over the whole body and wash off after 10 minutes.’
      • ‘It seems probable that in the future, synthetic pyrethroids will be of more interest than pyrethrum as possible delousing agents.’
      • ‘You can treat them with pyrethrum, white oil, soapy water or just squash them with your fingers.’
      • ‘You can purchase concentrated pyrethrum from a nursery or the garden supply section of your supermarket.’


Middle English (denoting pellitory): from Latin, from Greek purethron ‘feverfew’. The current senses (based on the former genus name) date from the late 19th century.