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