Leafy spurge
Encyclopedia
Euphorbia esula, commonly known as the Green Spurge or Leafy Spurge, is a species of spurge native to central and southern Europe
(north to England
, the Netherlands
, and Germany
), and eastward through most of Asia
north of the Himalaya to Korea
and eastern Siberia
.
It is a herbaceous
perennial plant
growing to 1-1.2 m tall, with several stems branched from the base. The stems are smooth, hairless or slightly hairy. The leaves
are small, lanceolate, 4-8.5 cm long and up to 1 cm broad, with a slightly wavy margin. The flower
s are small, produced in umbel
s with a basal pair of bright yellow-green petal-like bract
s. Clusters of the bracts appear in late spring, while the actual flowers do not develop until early summer. All parts of the plant contain a toxic white milky sap.
It reproduces readily by seed
s that have a high germination
rate and may remain viable in the soil for at least seven years. The seed capsules
open explosively, dispersing seed up to 5 m from the parent plant, and may be carried further by water and wildlife. Leafy Spurge also spreads vegetatively from the root
system, which is complex, reported to reach 8 m into the ground and 5 m across, and may have numerous buds.
There are two subspecies
and a hybrid subspecies:
possibly as a seed impurity in the early 19th century. First recorded from Massachusetts
in 1827, Leafy Spurge spread quickly and reached North Dakota
within about 80 years. It now occurs across much of the northern U.S., with the most extensive infestations reported for Montana
, North Dakota, Nebraska
, South Dakota
, and Wyoming
. It has been identified as a serious weed
on a number of national parks and on reserves of The Nature Conservancy
in eleven northern states. It is now classified as an invasive species
by the United States Department of Agriculture
. It was first recorded in Alberta, Canada
in 1933 and is also naturalised
in parts of South America
.
It displaces native vegetation in prairie habitats and fields through shading and by usurping available water and nutrients and through plant toxin
s that prevent the growth of other plants underneath it. It is an aggressive invader and, once present, can completely overtake large areas of open land. It is toxic as well.
Because of its persistent nature and ability to regenerate from small pieces of root, Leafy Spurge is extremely difficult to eradicate. Biological control
offers a highly promising management tactic for Leafy Spurge. Goat
s, apparently able to graze on the plant without ill effect, have been used on rail trails in Idaho
to clear leafy spurge from the trail
shoulders
. The U.S. Department of Agriculture has shown success using six European insects that feed on Leafy Spurge. These include a stem and root-boring beetle (Oberea erythrocephala), five root-mining flea beetle
s (Aphthona
spp.), and a shoot-tip gall midge (Spurgia esulae). Large scale field-rearing and release programs are carried out cooperatively by federal
and state officials
in many northern states. The results are not as immediate as when herbicides are used but, if pesticide use is kept to a minimum, large numbers of these insects build up within a few years and have shown impressive results.
Several systemic herbicide
s have been found to be effective if applied in June, when the flowers and seeds are developing, or in early-to-mid-September, when the plants are moving nutrients downward into the roots. Preliminary research suggests that chemical treatment in the fall followed by a spring burn to reduce seed germination may be an effective strategy for reducing Leafy Spurge infestations. Multiple treatments are necessary every year for several years, making leafy spurge control an extremely expensive undertaking. If left uncontrolled for a single year, Leafy Spurge can reinfest rapidly. Prescribed burning, in conjunction with herbicides, may also be effective.
. The unigenes have been used to develop cDNA microarrays that also include more than 4,000 additional cDNAs from cassava
(another Euphorb related to leafy spurge). These microarrays are being used to identify physiological processes and signals that regulate bud dormancy (one of the main reasons leafy spurge is difficult to control), and invasiveness.
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
(north to England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, and Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
), and eastward through most of Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
north of the Himalaya to Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
and eastern Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
.
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
perennial plant
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
growing to 1-1.2 m tall, with several stems branched from the base. The stems are smooth, hairless or slightly hairy. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are small, lanceolate, 4-8.5 cm long and up to 1 cm broad, with a slightly wavy margin. The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are small, produced in umbel
Umbel
An umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....
s with a basal pair of bright yellow-green petal-like bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s. Clusters of the bracts appear in late spring, while the actual flowers do not develop until early summer. All parts of the plant contain a toxic white milky sap.
It reproduces readily by seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s that have a high germination
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
rate and may remain viable in the soil for at least seven years. The seed capsules
Capsule (fruit)
In botany a capsule is a type of simple, dry fruit produced by many species of flowering plants. A capsule is a structure composed of two or more carpels that in most cases is dehiscent, i.e. at maturity, it splits apart to release the seeds within. A few capsules are indehiscent, for example...
open explosively, dispersing seed up to 5 m from the parent plant, and may be carried further by water and wildlife. Leafy Spurge also spreads vegetatively from the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
system, which is complex, reported to reach 8 m into the ground and 5 m across, and may have numerous buds.
There are two subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
and a hybrid subspecies:
- Euphorbia esula subsp. esula. Leaves broadest near apex; umbel bracts 5–15 mm. Throughout the range of the species.
- Euphorbia esula subsp. tommasiniana (Bertol.) Kuzmanov (syn. E. waldsteinii (Sojak) A.R.Smith; E. virgata Waldst. & Kit.). Leaves broadest at the middle; umbel bracts 12–35 mm. Eastern Europe, western Asia.
- Euphorbia esula nothosubsp. pseudovirgata (Schur) Govaerts. Hybrid between the above two subspecies.
As an invasive plant
Leafy Spurge was transported to the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
possibly as a seed impurity in the early 19th century. First recorded from Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
in 1827, Leafy Spurge spread quickly and reached North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
within about 80 years. It now occurs across much of the northern U.S., with the most extensive infestations reported for Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
, North Dakota, Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....
, South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
, and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
. It has been identified as a serious weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
on a number of national parks and on reserves of The Nature Conservancy
The Nature Conservancy
The Nature Conservancy is a US charitable environmental organization that works to preserve the plants, animals, and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive....
in eleven northern states. It is now classified as an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
by the United States Department of Agriculture
United States Department of Agriculture
The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...
. It was first recorded in Alberta, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
in 1933 and is also naturalised
Naturalisation (biology)
In biology, naturalisation is any process by which a non-native organism spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised....
in parts of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.
It displaces native vegetation in prairie habitats and fields through shading and by usurping available water and nutrients and through plant toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
s that prevent the growth of other plants underneath it. It is an aggressive invader and, once present, can completely overtake large areas of open land. It is toxic as well.
Because of its persistent nature and ability to regenerate from small pieces of root, Leafy Spurge is extremely difficult to eradicate. Biological control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
offers a highly promising management tactic for Leafy Spurge. Goat
Goat
The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...
s, apparently able to graze on the plant without ill effect, have been used on rail trails in Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
to clear leafy spurge from the trail
Trail
A trail is a path with a rough beaten or dirt/stone surface used for travel. Trails may be for use only by walkers and in some places are the main access route to remote settlements...
shoulders
Shoulder (road)
A hard shoulder, or simply shoulder, is a reserved area by the verge of a road or motorway. Generally it is kept clear of motor vehicle traffic...
. The U.S. Department of Agriculture has shown success using six European insects that feed on Leafy Spurge. These include a stem and root-boring beetle (Oberea erythrocephala), five root-mining flea beetle
Flea beetle
Flea beetles is a general name applied to the small, jumping beetles of the leaf beetle family . They make up the tribe Alticini, which is a part of the subfamily Galerucinae, though they were historically classified as a subfamily in their own right...
s (Aphthona
Aphthona
Aphthona is a genus of beetle, in the leaf beetle family Chrysomelidae, native to Europe and Asia. More specifically, Aphthona are flea beetles, meaning they have enlarged hind legs for jumping away from potential danger....
spp.), and a shoot-tip gall midge (Spurgia esulae). Large scale field-rearing and release programs are carried out cooperatively by federal
Federal government of the United States
The federal government of the United States is the national government of the constitutional republic of fifty states that is the United States of America. The federal government comprises three distinct branches of government: a legislative, an executive and a judiciary. These branches and...
and state officials
State governments of the United States
State governments in the United States are those republics formed by citizens in the jurisdiction thereof as provided by the United States Constitution; with the original 13 States forming the first Articles of Confederation, and later the aforementioned Constitution. Within the U.S...
in many northern states. The results are not as immediate as when herbicides are used but, if pesticide use is kept to a minimum, large numbers of these insects build up within a few years and have shown impressive results.
Several systemic herbicide
Herbicide
Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
s have been found to be effective if applied in June, when the flowers and seeds are developing, or in early-to-mid-September, when the plants are moving nutrients downward into the roots. Preliminary research suggests that chemical treatment in the fall followed by a spring burn to reduce seed germination may be an effective strategy for reducing Leafy Spurge infestations. Multiple treatments are necessary every year for several years, making leafy spurge control an extremely expensive undertaking. If left uncontrolled for a single year, Leafy Spurge can reinfest rapidly. Prescribed burning, in conjunction with herbicides, may also be effective.
As a model weed
Leafy spurge is being developed as a model to answer fundamental questions of weed biology. Over 55,000 ESTs have been sequenced from all plant tissues including tissues from plants that were cold-stressed, drought stressed, and plant being attacked by both flea beatles and gall midges. Analysis of the EST sequences indicated that 23,000 unique sequences representing more than 19,000 unigenes were obtained. These sequences are now available on GenbankGenBank
The GenBank sequence database is an open access, annotated collection of all publicly available nucleotide sequences and their protein translations. This database is produced and maintained by the National Center for Biotechnology Information as part of the International Nucleotide Sequence...
. The unigenes have been used to develop cDNA microarrays that also include more than 4,000 additional cDNAs from cassava
Cassava
Cassava , also called yuca or manioc, a woody shrub of the Euphorbiaceae native to South America, is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates...
(another Euphorb related to leafy spurge). These microarrays are being used to identify physiological processes and signals that regulate bud dormancy (one of the main reasons leafy spurge is difficult to control), and invasiveness.
External links
- Species Profile- Leafy Spurge (Euphorbia esula L.), National Invasive Species Information Center, United States National Agricultural LibraryUnited States National Agricultural LibraryThe United States National Agricultural Library is one of the world's largest agricultural research libraries, and serves as a National Library of the United States and as the library of the United States Department of Agriculture...
. Lists general information and resources for leafy spurge.