pyrethrum


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Related to pyrethrum: pyrethrin

pyrethrum

(pīrē`thrəm): see chrysanthemumchrysanthemum
, name for a large number of annual or perennial herbs of the genus Chrysanthemum of the family Asteraceae (aster family), some cultivated in Asia for at least 2,000 years.
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Pyrethrum

 

a genus of pubescent, perennial herbaceous plants of the family Compositae. The plants range in height from 5 to 150 cm. The alternate leaves are pinnatifid or, less frequently, entire. The small flowers are in heads, which are solitary or in two to 40 (less frequently, 100) corymbose inflorescences. The ray flowers are pistillate and ligulate, and the disk flowers are bisexual and tubular.

There are about 100 species of Pyrethrum, distributed in Europe (except the Far North), Asia, and North Africa. The USSR has approximately 55 species, found mostly in southern and mountainous regions. Some species accumulate pyrethrins —substances that are poisonous to insects and other invertebrates.

Two closely related species are cultivated: P. roseum (formerly P. carneum) and P. coccineum (formerly P. roseum). They grow in meadows and on the rocky slopes of the Caucasus, at elevations of 1,500 to 3,000 m. P. roseum, an herbaceous plant measuring 20 to 60 cm tall, has one or, less commonly, two or three flower heads. The leaves are not deeply pinnatifid, and the ray flowers are pink. The achenes, which are 2–3 mm long, are elongate and ribbed; they have a small crown. P. coccineum differs from P. roseum by its twice pinnatifid leaves. The ray flowers are pink or red. Both species contain substances in their inflorescences, stems, and leaves that have high insecticidal properties but are harmless to warm-blooded animals, including man. The Dalmatian pyrethrum (P. cinerariifolium) is cultivated as a source of insecticide. (It sometimes escapes cultivation.) The plant, which is native to the mountains of the Balkan Peninsula, is herbaceous and reaches a height of 15–45 cm. It has silvery gray twice or thrice pinnatifid leaves. The ray flowers are white or yellowish. The costomary (P. balsamita) is sometimes used as a source of insecticide, and the feverfew (P. parthenium), mainly varieties with yellow-green leaves, is used as a border ornamental. The genus Pyrethrum is often combined with the genera Leukanthemum and Chrysanthemum.

REFERENCE

Flora SSSR, vol. 26. Moscow-Leningrad, 1961.

T. G. LEONOVA

pyrethrum

[pī′rē·thrəm]
(materials)
A toxicant obtained in the form of dried powdered flowers of the plant of the same name; mixed with petroleum distillates, it is used as an insecticide.

pyrethrum

1. any of several cultivated Eurasian chrysanthemums, such as Chrysanthemum coccineum and C. roseum, with white, pink, red, or purple flowers

pyretic

Pathol of, relating to, or characterized by fever
3. any insecticide prepared from the dried flowers of any of these plants, esp C. roseum
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Lonyangapuo urged farmers to plant pyrethrum again since they partnered with five companies to buy the produce.
sertifer larvae showed that pyrethrum had the same effect with as low as 150 ml/100 dose and as high as 300 ml/100 l dose.
Across all time intervals, the highest mean mortality was recorded in plots that were pruned and treated with Pyrethrum 5EW.
Caption: Experimental fields are testing the efficiency of pyrethrums as part of an integrated pest management strategy.
Topical products containing Anacyclus pyrethrum extracts are already commercially available with functional, cosmeceutical claims.
Roots powder of Anacyclus pyrethrum is well known as sternutatory, sudorific and anti infectious (Doudach et al., 2012).
These stations were to provide the basic facilities for De Meillon to demonstrate the utility of indoor spraying with pyrethrum as a highly effective measure against adult, indoor resting anopheline mosquitoes.
The parent insecticide, Pyrethrum, is natural and is extracted from a chrysanthemum grown mainly in Kenya.
Attributes of 25 Tasmanian ferrosols under 5 forms of management (low-input pasture, high-input pasture, intermittent cropping, continuous cropping, and pyrethrum production) were assessed using field and laboratory techniques, to see how these attributes changed as the intensity of land management increased.