pyrethrum
/pai'ri:θrəm/
Học thuậtThân thiện
Definition
- Noun:
- A plant genus: A genus name used in older botanical classifications for certain plants, many of which are now classified under the genera Chrysanthemum or Tanacetum.
- An insecticidal plant: A perennial garden plant of Asiatic origin, with finely divided aromatic leaves and flowers ranging from white to pink-purple. The dried flower heads of this plant are processed to produce a natural insecticide.
- A specific plant species: A white-flowered pyrethrum species native to the Balkan region, characterized by leaves that are white and silky-hairy underneath. It is also a source of insecticide.
Usage Examples
- Noun:
- The farmer grows pyrethrum as a natural alternative to synthetic pesticides.
- Pyrethrum is derived from the dried flowers of certain chrysanthemum plants.
- This organic spray contains pyrethrum to control aphids.
Advanced Usage
- "Pyrethrum powder": The dried, crushed flower heads of the pyrethrum plant, used directly as an insecticide dust.
- He applied pyrethrum powder around the base of the plants to deter pests.
- "Pyrethrum extract": The concentrated active compounds (pyrethrins) extracted from pyrethrum flowers, used in liquid insecticide formulations.
- The pyrethrum extract is mixed with water before spraying.
Variants and Related Words
- Pyrethrin (noun): Any of several related insecticidal compounds that are the active ingredients found in pyrethrum flowers.
- Pyrethrins are effective against a wide range of insects.
- Pyrethroid (noun): A synthetic chemical compound modeled after the natural pyrethrins found in pyrethrum.
- Many commercial household insecticides contain synthetic pyrethroids.
Synonyms
- Insecticidal chrysanthemum: A descriptive term for the plant source.
- Dalmatian insect flower: A common name for the species of pyrethrum.
Related Terms and Context
- Natural insecticide: Pyrethrum is a key example of a botanical or natural insecticide.
- Botanical classification: The term illustrates changes in plant taxonomy, as the name Pyrethrum has been reclassified into other genera like .
Noun
- used in former classifications for plants later placed in genus Chrysanthemum and now often included in genus Tanacetum
- spring-flowering garden perennial of Asiatic origin having finely divided aromatic leaves and white to pink-purple flowers; source of an insecticide; sometimes placed in genus Chrysanthemum
- white-flowered pyrethrum of Balkan area whose pinnate leaves are white and silky-hairy below; source of an insecticide; sometimes placed in genus Chrysanthemum
- made of dried flower heads of pyrethrum plants