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From Wikipedia, the free encyclopedia
St John's wort (pronounced / sinjun's ˈwɝt/, rhyming with hurt) used alone refers to the species Hypericum perforatum, also known as Tipton's Weed or Klamath weed, but, with qualifiers, is used to refer to any species of the genus Hypericum. Therefore, H. perforatum is sometimes called Common St John's wort to differentiate it. The species of Hypericum have been placed by some in the family Hypericaceae, but more recently have been included in the Clusiaceae.[citation needed] Approximately 370 species of the genus Hypericum exist worldwide with a native geographical distribution including temperate and subtropical regions of North America, Europe, Asia Minor, Russia, India and China.
[edit] The plant
Hypericum perforatum is a yellow-flowering, rhizomatous, perennial herb indigenous to Europe, which has been introduced to the Americas and grows wild in many meadows. The common name comes from its traditional flowering and harvesting on St John's day, 24 June. The genus name Hypericum is derived from the Greek words hyper (above) and eikon (picture), in reference to the traditional use of the plant to ward off evil, by hanging plants over a picture in the house during St John's day. The species name perforatum refers to the presence of small oil glands in the leaves that look like windows, which can be seen when they are held against the light.
Although Hypericum perforatum is grown commercially in some regions of south east Europe, it is listed as a noxious weed in more than twenty countries. In pastures, St John’s wort acts as both a toxic and invasive weed.[1] It replaces useful vegetation to the extent of making productive land unviable or acts as an alien species in natural ecosystems. Ingestion by livestock can cause photosensitization, central nervous system depression, spontaneous abortion, and can lead to death. Effective herbicides for control of Hypericum include 2,4-D, picloram, and glyphosate. In western North America three beetles Chrysolina quadrigemina, Chrysolina hyperici and Agrilus hyperici have been introduced as biocontrol agents.
[edit] Identification
St John’s wort can be visually recognized by leaf and flower type. Yellow, five petaled flowers approximately 20 mm across occur between late Spring and early to mid Summer. Leaves exhibit obvious translucent dots when held up to the light, giving them a ‘perforated’ appearance, hence the plant's Latin name. When flowers or seed pods are crushed, a reddish/purple liquid is produced.
The translucent dots on the St John's wort leaves
[edit] Botanical description
St John's wort is a perennial plant with extensive, creeping rhizomes. Its stems are erect, branched in the upper section, and can grow to 1 m high. It has opposing, stalkless, narrow, oblong leaves which are 12 mm long or slightly larger. The leaves are yellow-green in color, with transparent dots throughout the tissue and occasionally with a few black dots on the lower surface. Its flowers measure up to 2.5 cm across, have five petals, and are colored bright yellow with conspicuous black dots. The flowers appear in broad cymes at the ends of the upper branches. The sepals are pointed, with glandular dots in the tissue. There are many stamens, which are united at the base into three bundles.
[edit] Chemical composition
Herb and flowers contain different flavonoids (rutin, hyperoside, isoquercetin, quercitrin, quercetin, I3,II8-biapigenin, amentoflavone, astilbin, miquelianin), phenolic acids (chlorogenic acid, 3-O-coumaroylquinic acid), different naphtodianthrones (hypericin, pseudohypericin, protohypericin, protopseudohypericin), phloroglucinols (hyperforin, adhyperforin) and essential oil (composed mainly of sesquiterpenes)[2][3][4].
[edit] Ecology
St John’s wort has a complex life cycle that includes a mature plant cycle with vegetative and sexual reproduction. It thrives in areas with either a winter- or summer-dominant rainfall pattern; however, distribution is restricted by temperatures too low for seed germination or seedling survival. Altitudes greater than 1500 m, rainfall less than 500 mm, and a daily mean January temperature greater than 24 degrees are considered limiting thresholds. Depending on environmental and climatic conditions, and rosette age, St John’s wort will alter growth form and habit to promote survival. Summer rains are particularly effective in allowing the plant to grow vegetatively, following defoliation by insects or grazing.
[edit] Hypericum poisoning (livestock)
[edit] Clinical signs
At large doses, St John's wort is poisonous to grazing livestock (cattle, sheep, goats, horses).[5]
Behavioural signs of poisoning are general restlessness and skin irritation. Restlessness is often indicated by pawing of the ground, head shaking, head rubbing, and occasional hindlimb weakness with knuckling over, panting, confusion and depression. Mania and hyperactivity may also result including running in circles until exhausted. Observations of thick wort infestations by Australian graziers include the appearance of circular patches giving hillsides a ‘crop circle’ appearance, possibly from this phenomenon. Animals typically seek shade and have reduced appetite. Hypersensitivity to water has been noted, and convulsions may occur following a knock to the head. Although general aversion to water is noted, some may seek water for relief.
Severe skin irritation is physically apparent, with reddening of non-pigmented and unprotected areas. This subsequently leads to itch and rubbing, followed by further inflammation, exudation and scab formation. Lesions and inflammation that occur are said to resemble the conditions seen in foot and mouth disease. Sheep have been observed to have face swelling, dermatitis, and wool falling off due to rubbing. Lactating animals may cease or have reduced milk production, pregnant animals may abort. Lesions on udders are often apparent. Horses may show signs of anorexia, depression (with a comatose state), dilated pupils, and injected conjunctiva.
[edit] Early diagnosis
Increased respiration and heart rate is typically observed while one of the early signs of St John’s wort poisoning is an abnormal increase in body temperature. Affected animals will lose weight, or fail to gain weight; young animals more affected than old animals. In severe cases death may occur, as a direct result of starvation, or because of secondary disease or septicaemia of lesions. Some affected animals may accidentally drown. Poor performance of suckling lambs (pigmented and non-pigmented) has been noted, suggesting a reduction in the milk production, or the transmission of a toxin in the milk.
[edit] Photosensitisation
Most clinical signs are caused by photosensitisation.[6] Plants may induce either primary or secondary photosensitisation: primary photosensitisation directly from chemicals contained in ingested plants, or secondary photosensitisation from plant-associated damage to the liver. Araya and Ford (1981) explored changes in liver function and concluded there was no evidence of Hypericum-related effect on the excretory capacity of the liver, or any interference was minimal and temporary. However, at high and continuous dose rates changes in blood plasma indicative of some liver damage have been observed.
Photosensitisation causes skin inflammation by a mechanism involving a pigment or photodynamic compound, which when activated by a certain wavelength of light leads to oxidation reactions in vivo. This leads to lesions of tissue, particularly noticeable on and around parts of skin exposed to light. Lightly covered or poorly pigmented areas are most conspicuous. Removal of affected animals from sunlight results in reduced symptoms of poisoning.
[edit] Use as spice
St John's wort is sometimes used for flavouring distilled spirits.[citation needed]
[edit] Use as antidepressant
St John's wort is today most widely known as a herbal treatment for depression. In some countries, such as Germany, it is commonly prescribed for mild depression, especially in children, adolescents, and where cost is a concern.[7] Standardized extracts are generally available over the counter – however, in some countries (such as Ireland) a prescription is required. Extracts are usually in tablet or capsule form, and also in teabags and tinctures.
[edit] Clinical evidence
Seedlings of St John's wort
Clinical studies of St John's wort preparations have mainly focused on the efficacy of the herb in clinical depression. Several studies and meta-analyses have found it to be effective in the treatment of mild to moderate depression, with fewer side effects than many conventional antidepressants. Other studies, including a major National Institutes of Health (NIH) study that focused on moderate to severe depression, have shown no improvements.[8]
[edit] Evidence for efficacy
An early meta-study indicated that extracts of Hypericum may be more efficacious than placebo for the treatment of mild to moderately severe depressive disorders.[9] This study, which covered the results from 23 smaller, earlier studies, is perhaps the most often cited by manufacturers and other supporters of St John's wort.
This study was later updated to include further studies, for a total of 27, to form a Cochrane Review. The updated review found that Hypericum preparations were significantly superior to placebo (rate ratio 2.47; 95% confidence interval 1.69 to 3.61) and similarly effective as standard antidepressants (single preparations 1.01; 0.87 to 1.16, combinations 1.52; 0.78 to 2.94).[10]
Another meta-analysis, with stricter inclusion criteria, found that Hypericum was more efficacious than placebo; and as efficacious as tricyclic antidepressants, with fewer adverse drug reactions. This meta-analysis showed that the response rate for St John’s wort was significantly greater than that for placebo (73.2 versus 37.9%, respectively, relative risk 1.48 and 95% CI 1.03–1.92) and similar to that observed with tricyclic antidepressants (64 versus 66.4% for St John’s wort and tricyclic antidepressants, respectively, relative risk 1.11 and 95% CI 0.92–1.29).[11]
There are some trials that show effectiveness of St. John's wort, beyond a placebo effect, on treating different types of depression.[12][13][14][15][16][17][18] A 2006 study involving 150 patients with minor depressive symptoms or dysthymia found that St John's wort has a clinically significant effect in patients with minor depression, but not those suffering from dysthymia. It was concluded that St John's wort can be effective in the treatment of people with minor depression with a Hamilton Depression Scale for Depression (HAM-D) score of up to 17.[19] The British Medical Journal has recommended that the results of the randomized controlled trials of St John's Wort should be interpreted with caution, as many did not use standardised preparations or homogenous populations, and doses of antidepressants varied.[9] A major review of the efficacy of St. John's Wort cautioned that the pharmaceutical quality of various preparations on the market may vary considerably.[10]
[edit] Evidence against efficacy for Major Depressive Disorder
A major study funded by the NIH in the United States failed to find any evidence that Hypericum extract of St John's wort was effective in treating moderate to severe cases of major depression (Hypericum Depression Trial Study Group, 2002). This study involved 340 patients, diagnosed with Major Depressive Disorder based on DSM-IV criteria and assessed using Hamilton Depression Rating Scale (HAM-D) and Clinical Global Impression (CGI) scores. The trial was a multi-centre randomised double-blind placebo-controlled trial, comparing one preparation of St John's wort (Li 160) to the antidepressant sertraline, and to placebo. No statistically significant effect was garnered from Li 160. Sertraline was also no better than placebo in this study, based on the primary outcome measure (the HAM-D).[8] The authors of the study themselves, as well as several others pointed out the low assay sensitivity of this study, and how only limited conclusions can be drawn from its results.[20] [21]
[edit] Pharmacology
The exact mechanism by which St John's wort — and even conventional antidepressants — functions is unclear and subject to conjecture. The St John's wort mechanism is believed to involve inhibition of serotonin (5-HT) reuptake, much like the conventional selective serotonin reuptake inhibitor (SSRI) antidepressants.[22] The major active antidepressive constituents in St John's wort are thought to be hyperforin and hypericin, although other biologically active constituents present, for example, flavonoids and tannins, may also be involved.[23][24][25]
Some believe that hyperforin is the major constituent responsible for antidepressant activity, and it has been shown to inhibit the uptake of 5-HT, dopamine, noradrenaline, GABA and glutamate. [24] On the other hand, a hyperforin free extract of St John's wort (Ze 117 - Remotiv) has been shown to still have significant antidepressive effects.[12][13]
[
From Wikipedia, the free encyclopedia
Verbascum thapsus (Great Mullein or Common Mullein) is a species of mullein native to Europe, northern Africa and Asia, and introduced in the Americas and Australia.
It is a hairy biennial plant that can grow to 2 m or more tall. Its small yellow flowers are densely grouped on the tall stem, which bolts from a large rosette of leaves. It grows in a wide variety of habitats, but prefers well-lit disturbed soils, where it can appear soon after the ground receives light, from long-lived seeds that persist in the soil seed bank. It is a common weedy plant that spreads by prolifically producing seeds, but rarely becomes aggressively invasive since its seed require open ground to germinate. It is a very minor problem for most agricultural crops since it is not a very competitive species, being intolerant of shade from other plants and unable to survive tilling. It also hosts many insects, some of which can be harmful to other plants. Although individuals are easy to remove by hand, populations are difficult to eliminate permanently.
It is widely used for herbal remedies with emollient and astringent properties. It is especially recommended for coughs and related problems, but also used in topical applications against a variety of skin problems. The plant was also used to make dyes and torches.
[edit] Description
Verbascum thapsus is a dicotyledonous biennial that produces a rosette of leaves in its first year of growth.[1][2] The leaves are large, up to 50 cm long, and are covered with woolly, silvery hairs. The second year plants normally produce a single unbranched stem 1–2 m tall, with some plants reportedly having stems reaching up to 3.5 m tall.[3] In the east of its range in China, it is however only reported to 1.5 m tall.[4] The tall pole-like stems end in a dense spike of flowers,[1] that can occupy up to half the stem length. All parts of the plants are covered with star-shaped trichomes.[4][5] Its chromosome number is 2n = 36.[6]
On flowering plants the leaves are alternately arranged up the stem. The leaves are thick, and decurrent on the stem, with much variation especially between the upper and lower leaves on the stem, with leaf shape ranging from between oblong to oblanceolate and ranging in size up to 50 cm long and 14 cm across (19 inches long and 5 inches wide).[7][8] They become smaller higher up the stem,[1][2] and less strongly decurrent lower down the stem.[1] The flowering stem is solid and 2–2.5 cm (nearly an inch) across, and occasionally branched just below the inflorescence,[2] usually when damaged.[9] After flowering and seed release the stem and fruits usually persist in winter[10] after drying into hard, stiff structures topped with densely packed, ovoid shaped, dry seed capsules. The dried stems are most often dark brownish, and often persist standing until the next spring or even into the next summer. The plants produce a shallow taproot.[8]
The flowers are pentamerous with five stamen that are fused to the petals and a 5-lobed calyx tube and a 5-petalled corolla, the latter bright yellow and an 1.5–3 cm (0.5–1 inch) wide. The flowers are almost sessile, with very short pedicels (2 mm, 0.08 in). The five stamens are of two types, with the three upper stamens being shorter, with filaments covered by yellow or whitish hairs, and having smaller anthers, while the lower two stamens have glabrous filaments and larger anthers.[5]A[›] The plant produces small ovoid (6 mm, 0.24 in) capsules that split open by way of two valves, each capsule containing large numbers of minute brown seeds less than a millimetre (0.04 in)[11] in size, with longitudinal ridges. A white-flowered form V. thapsus f. candicans occurs.[12] Flowering lasts for up to three months from early to late summer (June to August in northern Europe),[2] with flowering starting at the bottom of the spike and progressing irregularly up the spike with each flower open for part of a day with only a few flowers open at the same time produced around the stem.[10]
[edit] Distribution and introduction
Verbascum thapsus has a wide native range including Europe, northern Africa and Asia, from the Azores and Canary Islands east to western China, north to the British Isles, Scandinavia and Siberia, and south to the Himalayas.[4][13][14] In northern Europe, it grows from sea level up to 1,850 m altitude,[2] while in China it grows at 1,400-3,200 m altitude.[4]
It has been introduced throughout the temperate world, and is established as a weed in Australia, New Zealand, tropical Asia, La Réunion, North America, Hawaii, Chile, Hispaniola and Argentina.[14][15][16][17] It has also been reported in Japan.[18]
In the United States it was imported very early in the 18thB[›] century and cultivated for its medicinal and piscicide property. By 1818, it had begun spreading so much that Amos Eaton thought it was a native plant.C[›][8][19] In 1839 it was already reported in Michigan and in 1876, in California.[8] It is now found commonly in all the states.[20] In Canada, it most common in Southern Quebec, Ontario and British Columbia, and in the Maritime Provinces, with scattered populations in between.[21][22]
[edit] Taxonomy and nomenclature
For the purpose of botanical nomenclature, Verbascum thapsus was first described by Carolus Linnaeus in his 1753 Species Plantarum. The specific epithet thapsus had been first used by Theophrastus (as θάψος, "thapsos")[23] for an unspecified herb from the Ancient Greek settlement of Thapsos, near modern Syracuse, Sicily,[23][24] though it is often assimilated to the ancient Tunisian city of Thapsus.[25] Within Verbascum, it classified under section Bothrosperma subsect. Fasciculata.[26]
At the time, no type specimen was specified, as the practice only appeared later, in the 19th century. When a lectotype (type selected amongst original material) was designated, it was assigned to specimen 242.1 of Linnaeus' herbarium, the only V. thapsus specimen. The species had previously been designated as type species for Verbascum.[27] European plants exhibit considerable phenotypical variation,[21] which has led to the plant acquiring many synonyms over the years.[28][29] Introduced American populations show much less variation.[21]
Type specimen(s)
- Lectotype: (LINN-242.1). Designated by L. H. Cramer, in Dassanayake & Fosberg, A Revised Handbook to the Flora of Ceylon 3: 389 (1981)[30]
[edit] Subspecies and hybrids
There are three subspecies:
- V. thapsus subsp. thapsus; type, widespread.
- V. thapsus subsp. crassifolium (Lam.) Murb.; Mediterranean region and to 2000 metres in southwestern Austria.[31] (syn. subsp. montanum (Scrad.) Bonnier & Layens)
- V. thapsus subsp. giganteum (Willk.) Nyman; Spain, endemic.
In all subspecies but the type, the lower stamens are also pilose (having scattered straight long soft hairs).[32] In subsp. crassifolium, the hairiness is less dense and often absent from the upper part of the anthers, and lower leaves are hardly decurrent and have longer petioles[31], whereas in subsp. giganteum, the hairs are densely white tomentose, and lower leaves strongly decurrent. Subsp. crassifolium also differs from the type in having slightly larger flowers, which measure 15–30 mm wide, whereas in the type they are 12–20 mm in diameter.[31] Both subsp. giganteum and subsp. crassifolium were originally described as species.[1] Other described subspecies that have not been widely accepted include subsp. martinezii (Valdés) A.Galán and J.A.V.Orellana (=V. giganteum subsp. martinezii Valdés), subsp. litigiosum (=V. litigiosum Samp.)[33] and subsp. langei.
The plant is also parent to several hybrids (see table). Of these, the most common is V. × semialbum Chaub. (× V. nigrum).[6] All occur in Eurasia,[6] and three, V. × kerneri Fritsch, V. × pterocaulon Franch. and V. × thapsi L. (syn. V. × spurium W.D.J.Koch), have also been reported in North America.[34][36]
[edit] Common names
V. thapsus is known by a variety of names. The standard English name used by authorities in its native area is Great Mullein.[37][38][39][40] In North America, "Common mullein" is the usual name.[41][42] In the 19th century it had well over 40 different common names in English alone. Some of the more whimsical ones included "Hig candlewick", "Bullicks lungwort", "Adams-rod", "Feltwort", "Hare's-beard" and "Ice-leaf".[43] Vernacular names include innumerable references to the plant's hairiness: "Woolly", "Velvet" or "Blanket Mullein",[40][44] "Beggar's", "Moses'", "Poor Man's", "Our Lady's" or "Old Man's Blanket",[39][42][45] and so on ("Flannel" is another common generic name).
Some names refer to the plant's size and shape: "Shepherd's Club(s)" or "Staff", "Aaron's Rod" (a name it shares with a number of other plants with tall, yellow inflorescences), and a plethora of other "X's Staff" and "X's Rod".[39][42][46] The name "Velvet" or "Mullein Dock" is also recorded, where "dock" is a British name applied to any broad-leaved plant.[47]
[edit] Ecology
V. thapsus grows best where there is little competition
Great Mullein most frequently grows as a colonist of bare and disturbed soil, usually on sandy or chalky soils.[6] This is in part due to its intolerance of shade and the very long periods during which the seeds can remain dormant before germination. It is not an agricultural weed, although its presence can be very difficult to completely eradicate, and is especially problematic in overgrazed pastures.[9][11][8] The species is considered a noxious weed in Colorado, United States (Class C),[48] Hawaii[49] and Victoria, Australia (regionally prohibited in the West Gippsland region, and regionally controlled in several others).[50]
It grows best in dry, sandy or gravelly soils, although it can grow in a variety of habitats, including banksides, meadows, roadsides, forest clearings and pastures. It germinates almost solely in bare soil, at temperatures between 10 °C and 40 °C.[9] This ability to grow in a wide range of habitats has been linked to strong phenotype variation rather than adaptation capacities.[51] While it can germinate in total darkness if proper conditions are present (tests give a 35% germination rate under ideal conditions), in the wild, it will only do so if the seeds are exposed, or very close to the soil surface. While it can also appear in areas where some vegetation exist, growth of the rosettes on bare soil is four to seven times more rapid.[9]
Megachilidae bees, notably Anthidium species, use the hair in making their nests.[10] The seeds are generally too small for birds to feed on,[10] although the American Goldfinch has been reported to consume them.[52] Other bird species have been reported to consume the leaves (Hawaiian Goose)[53] or flowers (Palila)[54] of V. thapsus, or to use the plant as a source when foraging for insects (White-headed Woodpecker).[55]
[edit] Life cycle
Great Mullein is a biennial and generally requires winter dormancy before it can flower.[9] This dormancy is linked to starch degradation in the root activated by low temperatures, and gibberellin application bypasses this requirement.[56] Seeds germinate in spring and summer most often when exposed to light, those that germinate in autumn produce plants that overwinter if they are large enough with rosettes less than 15 cm (5.9 in) across dying in winter. After flowering the entire plant usually dies at the end of its second year[9] but some individuals, especially in the northern parts of the range, require a longer growth period and flower in their third year. Under longer growing conditions, some individuals flower in the first year.[57] Triennial individuals were found to produce fewer seeds than biennial and annual ones. While year of flowering and size are linked to the environment, most other characteristics appear to be genetic.[58]
A given flower is open only for a single day, opening before dawn and closing in the afternoon.[21] Flowers are autogamous and protogynous, with female parts maturating first,[21] and will self-pollinate if they have not been pollinated by insects during the day. While many insects visit the flowers, only some bees actually accomplish pollination. V. thapsus' flowering period lasts from June to August in most of its range, extending to September or October in warmer climates.[9][8][11] Visitors include halictid bees and hoverflies.[10] The hair on lower stamens may serve to provide footholds for visitors.[21]
The seeds maintain their germinative powers for decades, up to a hundred years, according to some studies.[59] Because of this, and because the plant is an extremely prolific seed bearer (each plant produces hundreds of capsules, each containing up to 700+ seeds,[21] with a total up to 180,000[8][9] or 240,000[11] seeds), it remains in the soil seed bank for extended periods of time, and can sprout from apparently bare ground,[9] or shortly after forest fires long after previous plants have died.[11] Its population pattern is typically an ephemeral adult population and long periods of dormancy as seeds.[21] Great Mullein rarely establishes on new grounds without human intervention because its seeds are not dispersed very far. Seed dispersion requires the stem to be moved by wind or animal movement; 75% of the seeds fall within 1 m of the parent plant, and 93% fall within 5 m.[9]
[edit] Agricultural impacts and control
Great Mullein is no longer considered a serious agricultural weed because it cannot compete with established plants, and is easily crowded out in cultivation,[21] except in areas where vegetation is sparse to begin with, such as Californian semi-desert areas of the Eastern Sierra Nevada. In such ecological contexts, it crowds out native herbs and grasses. Its tendency to appear after forest fires also disturbs the normal ecological succession.[9][11] In the past, when fields were hand cultivated, it was a serious pest species and called a troublesome weed.
Despite not being an agricultural weed in itself, it hosts a number of insects and diseases, including both pests and beneficial insects.[60] It is also a potential reservoir of the cucumber mosaic virus, powdery mildew (Erysiphum cichoraceum) and Texas root rot.[21][61] A study found V. thapsus hosts insects from 29 different families. Most of the pests found were western flower thrips (Frankliniella occidentalis), Lygus species such as the tarnished plant bug (L. lineolaris), and various spider mites from the family Tetranychidae. These make the plant a potential reservoir for overwintering pests.[60]
Other insects commonly found on Great Mullein feed exclusively on Verbascum species in general or V. thapsus in particular. They include mullein thrips (Haplothrips verbasci),[60] Gymnaetron tetrum and the Mullein Moth (Cucullia verbasci).[8] Useful insects are also hosted by Great Mullein, including predatory mites of the Galendromus, Typhlodromus and Amblyseius genera (Phytoseiidae), the minute pirate bug (Orius tristicolor)[60] and the mullein plant bug (Campylomma verbasci).[62] The plant's ability to host both pests and beneficials makes it potentially useful to maintain stable populations of insects used for biological control in other cultures, like Campylomma verbasci and Dicyphus hesperus (Miridae), a predator of whiteflies.[63] A number of pest Lepidoptera species, including the Stalk Borer (Papaipema nebris) and Gray Hairstreak (Strymon melinus), also use V. thapsus as a host plant.[64]
The hairy leaves are resistant to grazing and contact herbicides.
Control of the plant, when desired, is best managed via mechanical means, such as hand pulling and hoeing, preferably followed by sowing of native plants. Animals rarely graze it because of its irritating hairs, and liquid herbicides require surfactants to be effective, as the hair causes water to roll off the plant, much like the lotus effect. Burning is ineffective, as it only creates new bare areas for seedlings to occupy.[9][11][8] G. tetrum and Cucullia verbasci usually have little effect on V. thapsus populations.[8] Goats and chickens have been proposed to control Mullein.[9] Effective (when used with a surfactant) contact herbicides include glyphosate,[8][11] triclopyr[8] and sulfurometuron-methyl.[11] Ground herbicides, like tebuthiuron, are also effective, but recreate bare ground and require repeated application to prevent regrowth.[9]
نوشته شده در سه شنبه دهم اردیبهشت 1387ساعت 19:19 توسط عماد..ن... emperor
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