Pyrethrum refers to several Old World plants of the genus "
Chrysanthemum" (e.g., "C. coccineum") which are cultivated as ornamentals for their showy flower heads. It is also the name of a natural insecticidemade from the dried flower heads of "C. cinerariifolium" and "C. coccineum". Pyrethrum was used for centuries as an insecticide. ["Bioaromatica" [http://www.aromatica.hr/eng/page.asp?id=buhac&sub=buhac3 The history of pyrethrum] ] and as a lice remedy ("Persian Insect Powder," "Persian Pellitory") in the Middle East. It was sold worldwide under the brand Zacherlinby Austrian industrialist J. Zacherl.US patent reference| number = 308172| y = 1884| m = 11| d = 18| inventor = Johann Zacherl| title =Pyrethrum Soap]
Some members of "Chrysanthemum", including these two, are placed in another genus, "
Tanacetum", by some authorities. Both genera are members of the daisy (or aster) family, Asteraceae. They are perennial plants with a daisy-like appearance and white petals.
*"C. cinerariifolium" is called the Dalmatian chrysanthemum, denoting its origin in that region of the Balkans (
Dalmatia). It looks more like the common daisy than other pyrethrums. Its flowers, typically white with a yellow center, grow from numerous fairly rigid stems. Plants have blue-green leaves and grow to between 45 to 60 cm in height. The plant is economically important as a natural source of insecticide. The flowers are pulverized and the active components called pyrethrins, contained in the seed cases, are extracted and sold in the form of an oleoresin. This is applied as a suspension in water or oil, or as a powder. Pyrethrins attack the nervous systems of all insects, and inhibit female mosquitoes from biting. When not present in amounts fatal to insects, they still appear to have an insect repellenteffect. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides and are non-persistent, being biodegradable and also breaking down easily on exposure to light. They are considered to be amongst the safest insecticides for use around food. Kenyaproduced 90% (over 6,000 tonnes) of the world's pyrethrum in 1998, called "py" for short. Production in Tanzaniaand Ecuadoris also significant.
*"C. coccineum", the Persian chrysanthemum, is native to
Caucasusand looks somewhat like a daisy. It produces large white, pink or red flowers. The leaves resemble those of ferns, and the plant grows to between 30 and 60 cm in height. The flowering period is June to July in temperate climates (Northern hemisphere). "C. coccineum" also contains insecticidal pyrethrum substances but it is a relatively poor source compared to "C. cinerariifolium".
*Other species such as "C. balsamita" and "C. marshalli" also contain insecticidal substances, but are less effective than the two species mentioned above.
Pyrethroids are synthetic insecticides based on natural pyrethrum ( pyrethrins); one common example is permethrin. A common formulation of pyrethrin is in preparations containing the synthetic chemical piperonyl butoxide: this has the effect of enhancing the toxicity to insects and speeding the effects when compared with pyrethrins used alone. These formulations are known as "synergized pyrethrins".
Because of the natural insecticidal properties of the pyrethrums, they are used as
companion plants, to repel pest insects from nearby crops. One might, for instance, plant them among broccoli plants in order to protect them from any of several insect pests. They are thought to repel aphids, leafhoppers, spider mites, harlequin bugs, ticks, pickleworms and imported cabbage worms, among others.
Common names for "Chrysanthemum cinerariaefolium" include:
*Dalmatian Insect Flower
Common names for "Chrysanthemum coccineum" include:
*Persian Insect Flower
*Caucasian Insect Powder Plant
List of companion plants
* [http://npic.orst.edu/factsheets/pyrethrins.pdf Pyrethrins and Pyrethroids Fact Sheet - National Pesticide Information Center]
* [http://www.andover.edu/news/documents/B-ChemicalFactSheet.pdf Pyrethrins and pyrethroids on the EXTOXNET]
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Pyrethrum — ist ein Insektizid, das aus den Blüten von verschiedenen Tanacetum Arten gewonnen wird. Die Hauptwirkstoffe sind Pyrethrine, außerdem Cinerine und Jasmoline. Inhaltsverzeichnis 1 Herstellung 2 Anbau 3 Wirtschaftliche Bedeutung … Deutsch Wikipedia
Pyrethrum — Saltar a navegación, búsqueda Pyrethrum puede referirse a: El nombre común de la planta Chrysanthemum cinerariaefolium El sinónimo del género botánico Tanacetum Obtenido de Pyrethrum Categoría: Wikipedia:Desambiguación … Wikipedia Español
Pyrethrum — (P. Gärtn.), aus mehren Arten von Chrysanthemum gebildete Pflanzengattung aus der Familie der Compositae Senecionideae Anthemideae, 19. Kl. 2. Ordn. L.; Arten: P. Myroni, mit gelben Blüthen; P. indicum, in China, Japan, Ostindien, strauchartig,… … Pierer's Universal-Lexikon
Pyrethrum — Pyrethrum, s. Chrysanthemum … Meyers Großes Konversations-Lexikon
Pyrethrum — Pyrĕthrum, Pflanzenart, s. Chrysanthemum … Kleines Konversations-Lexikon
pyrethrum — ► NOUN 1) an aromatic plant of the daisy family, typically with brightly coloured flowers. 2) an insecticide made from the dried flowers of these plants. ORIGIN Greek purethron feverfew … English terms dictionary
pyrethrum — [pī reth′rəm, pīrē′thrəm] n. [ModL < L < Gr pyrethron, feverfew < pyr, FIRE] 1. a perennial plant (Chrysanthemum coccineum) of the composite family, widely grown for the white, pink, red, or purple flower heads 2. an insecticide made… … English World dictionary
pyrethrum — /puy ree threuhm, reth reuhm/, n. 1. any of several chrysanthemums, as Chrysanthemum coccineum, having finely divided leaves and showy red, pink, lilac, or white flowers, cultivated as an ornamental. 2. any of several chrysanthemums, as C.… … Universalium
Pyrethrum — Py|re|thrum auch: Py|reth|rum 〈n.; s, re|thra〉 aus Wucherblumen (Chrysanthemen) gewonnenes Insektengift [<grch. pyrethron; zu pyr „Feuer“] * * * Py|re|th|rum, das; s, …ra [griech. pýrethron = Mauerkraut, zu: pỹr ↑ (pyro , Pyro ), wohl wegen… … Universal-Lexikon
Pyrethrum — Pyrèthre Pyrèthre … Wikipédia en Français