Taxonomic name: Euphorbia esula (Linnaeus)
Synonyms: Euphorbia intercedens, Euphorbia pseudovirgata, Galarhoeus esula, Tithymalus esula
Common names: Esels-Wolfsmilch (German), leafy spurge (English), spurge (English), wolf's milk (English)
Organism type: herb Native to Europe and temperate Asia, Euphorbia esula (leafy spurge) is found throughout the world, with the exception of
Australia. This aggressive invader displaces native vegetation by shading and using up available water and nutrients, and by plant toxins that prevent the growth of other plants beneath it. Description
Euphorbia esula has hairless, non-woody stems that sprout from a woody crown root and have alternate, frosted, lance-shaped leaves that are bluish-green in colour. Its height ranges from 5- 90cm. During summer, this plant has yellow bracts (leaf-like petals), which contain greenish-yellow flower clusters at the top of the stem. It grows in very dense stands. An identifying feature is the milky white substance that seeps from the plant when torn or cut. Occurs in:
agricultural areas, natural forests, range/grasslands, ruderal/disturbed, scrub/shrublands, urban areas Habitat description
Euphorbia esula prefers areas of full sunlight and dry soil but can tolerate a variety of habitats, such as roadsides. E. esula is found on prairies, savannas, and woodlands. General impacts
Euphorbia esula develops extensive root systems that can reach 4.5m below the soil surface and up to 10m laterally. E. Esula outcompetes native vegetation by consuming available water and nutrients through its extensive root system, sprouting new plants out of the existing root system, and by shading sunlight and excreting toxins that inhibit growth of surrrounding plants. These toxins also repel cattle and horses. An infestation of leafy spurge eliminates forage-worthy grasses while providing no nutritional value. It forms dense stands in early spring, shading out the native plants beneath as they emerge, stunting or killing them. An extensive and resilient underground root structure is fast to replace any shoots that become damaged during the growing season, prior to the plant's flowering. By midsummer, leafy spurge produces high yields of pollen and seed, up to 3,400 pounds of seed per acre, setting the stage for the next spring, and further spread. For humans who make accidental contact with the milky sap contained in leafy spurge the consequences range from minor skin irritation to total blindness if the liquid is rubbed on the eyes. Grazing cattle, horses and sheep tend to avoid the plant, but if they must eat it, the result can be digestive problems, weakness, even death (D'Ancona, J., 2004). Uses
Euphorbia esula is a good food source for sheep and goats. Geographical range
Native range: E. esula is native to Europe and temperate Asia.
Known introduced range: E. esula is now found throughout the world, except in Australia. Introduction pathways to new locations
Agriculture: May be accidentally mixed in agricultural seed.
Ignorant possession:
Landscape/fauna "improvement": May be introduced for its colorfully yellow bracts.
Local dispersal methods
Acclimatisation societies (local): Plants can spread four feet per year vegetatively.
On animals: Management information
Physical: Hand-pulling and cutting have been found to be ineffective and could actually increase the spread.Chemical: Chemical control is not completely effective because the root system blocks the downward movement of the herbicides. The extent of most invasions is so wide that spraying is impractical and too costly. Also, most herbicides for E. esula are detrimental to desirable broadleaved range plants. Herbicides and prescribed burning can be effective if repeated and done at the appropriate time. Biological: Biological control seems to be the most viable control measure. Species under consideration are the cerambyciid long-horned beetle, chrysomelid flea beetles, and the cecidomyiid midge. Sheep and goats, which feed heavily on this plant, have also been shown to be effective in controlling this plant's spread. Integrated pest management: Studies have shown than integrated approach to leafy spurge control is more effective than following a single option. The Ecological Areawide Management (TEAM) of the Leafy Spurge programme found that an IPM (integrated pest management approach), with an integration of multiple tools (herbicides, flea beetles, sheep and burning) proved to be effective in leafy spurge control programmes (Anderson et al., 2003).Aphthona spp. flea beetles on both the leafy spurge control and the biological control agent populations it was found that Leafy spurge density was reduced more rapidly when A. nigriscutis or a mixture of A. czwalinae and A. lacertosa was combined with a fall-applied treatment of picloram plus 2,4-D than when either method was used alone. The combination treatment reduced leafy spurge density 3 to 5 yr earlier than did either the herbicides or the biocontrol agents alone and once reduced, the Aphthona flea beetles maintained acceptable control for at least 7 yr. Spring-applied herbicides eliminated the adult food source and negatively affected the flea beetle establishment, but fall-applied treatments did not reduce the flea beetle establishment or its reproduction. The combination treatment was most successful when used with established Aphthona spp. populations that were not increasing in size or reducing leafy spurge density. Land managers could realize a three- to five fold cost savings with the combination treatment compared with herbicides alone (Lym et al., 2002).
In studies using microcosms in a greenhouse consisting of potted, caged plants of E. esula / E.virgata, combinations of Fusarium oxysporum, Rhizoctonia solani, or both fungi with adults and larvae of the flea beetle Aphthona spp. caused significantly greater rates of injury to E. esula / E.virgata than any single agent. The results support the idea that supplementing flea beetle establishments with plant pathogens can be an effective means of both causing higher rates of successfully impacted release sites and greater biocontrol impact at individual release sites (Caesar, A. J. 2003). Reproduction
Euphorbia esula produces flowers following its first year. Each plant can produce up to 200 seeds, of which 60% to 80% will germinate. It also grows new plants from buds on lateral secondary roots. The capsule ripens, bursts, and shoots seeds 4.5m away from the parent plant. It also sprouts from crown and root buds. Lifecycle stages
Euphorbia esula is a perennial. Showy yellowish-green bracts are seen during part of the year. Seeds can lie dormant for up to 7 years. Plant longevity not found. This species has been nominated as among 100 of the "World's Worst" invaders Reviewed by: Major update under progress
Compiled by: Profile revision: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
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Last Modified: Friday, June 26, 2009
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