1An aromatic plant of the daisy family, typically having feathery foliage and brightly colored flowers.
- ‘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).’
- ‘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.’
- ‘This is the area where significant cash crops are grown, including pyrethrum (a flower that produces a natural insecticide), coffee and tea.’
- ‘When I looked closely I could see the truck had a PyGanic label with the iconic pyrethrum flower on the side.’
- 1.1 An insecticide made from the dried flowers of the pyrethrum plant.
- ‘Adult mosquitoes were obtained from houses within a village by resting and pyrethrum knockdown collections.’
- ‘By the mid 1800s, the heads of chrysanthemum flowers were used to obtain pyrethrum, and rotenone was extracted from the derris plant.’
- ‘For body lice, use pyrethrum with piperonyl butoxide lotion over the whole body and wash off after 10 minutes.’
- ‘‘That's pyrethrum,’ said Niko ‘it's used as an insecticide.’’
- ‘It seems probable that in the future, synthetic pyrethroids will be of more interest than pyrethrum as possible delousing agents.’
- ‘A natural pyrethrum insecticide is cheaper, less harmful and just as effective as those chemical poisons to kill spiders.’
- ‘You can treat them with pyrethrum, white oil, soapy water or just squash them with your fingers.’
- ‘Rotenone and pyrethrum don't work, even if applied more frequently.’
- ‘You can purchase concentrated pyrethrum from a nursery or the garden supply section of your supermarket.’
- ‘Geoff reckons to use a contact spray like pyrethrum which breaks down within about 24 hours.’
- ‘Pesticides that are approved for organic farming include copper, sulfur, petroleum distillates, and pyrethrum.’
- ‘Daisy plants were first used centuries ago as a lice remedy in the Middle East, and this led to the discovery of pyrethrum insecticides.’
- ‘The spray does not control the adults, so you can either handpick the adults or spray them with pyrethrum insecticide.’
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.
We take a look at several popular, though confusing, punctuation marks.