Clover, also called trefoil, are plants of the genus Trifolium, consisting of about 300 species of flowering plants in the legume family Fabaceae originating in Europe. The genus has a cosmopolitan distribution with highest diversity in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes on mountains in the tropics. They are small annual, biennial, or short-lived perennial herbaceous plants, typically growing up to 30 centimetres (12 in) tall. The leaves are trifoliate, with stipules adnate to the leaf-stalk, and heads or dense spikes of small red, purple, white, or yellow flowers; the small, few-seeded pods are enclosed in the calyx. Other closely related genera often called clovers include Melilotus and Medicago.
Trifolium repens, the white clover, is a herbaceous perennial plant in the bean family Fabaceae. It is native to Europe, including the British Isles, and central Asia and is one of the most widely cultivated types of clover. It has been widely introduced worldwide as a forage crop, and is now also common in most grassy areas of North America, Australia and New Zealand. The species includes varieties often classed as small, intermediate and large, according to height, which reflects petiole length. The term 'white clover' is applied to the species in general, 'Dutch clover' is often applied to intermediate varieties, and 'ladino clover' is applied to large varieties.
Melilotus, known as melilot, sweet clover, and kumoniga, is a genus in the family Fabaceae. Members are known as common grassland plants and as weeds of cultivated ground. Originally from Europe and Asia, it is now found worldwide.
Potyvirus is a genus of positive-strand RNA viruses in the family Potyviridae. Plants serve as natural hosts. Like begomoviruses, members of this genus may cause significant losses in agricultural, pastoral, horticultural, and ornamental crops. More than 200 species of aphids spread potyviruses, and most are from the subfamily Aphidinae. The genus contains 190 species and potyviruses account for about thirty percent of all currently known plant viruses.
The genus Canna is susceptible to certain plant viruses, which may result in spotted or streaked leaves, in a mild form, but can finally result in stunted growth and twisted and distorted blooms and foliage. Known species of virus are:
Bean yellow mosaic virus is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae. Like other members of the Potyvirus genus, it is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus is a filamentous particle that measures about 750 nm in length. This virus is transmitted by species of aphids and by mechanical inoculation.
Bidens mottle virus (BiMoV) is a pathogenic plant virus in the plant virus family Potyviridae. BiMoV is a flexuous filamentous particle, 720 nm long, and belongs to the Potyviridae genus Potyvirus. Like other viruses in this genus, Bidens mottle virus is transmitted both mechanically by sap and by aphids in a stylet-borne fashion.
Cacao swollen shoot virus (CSSV) is a plant pathogenic virus of the family Caulimoviridae that primarily infects cacao trees. It decreases cacao yield within the first year of infection, and usually kills the tree within a few years. Symptoms vary by strain, but leaf discoloration, stem/root swelling, and die-back generally occur. The virus is transmitted from tree to tree by mealybug vectors. It was first discovered in Ghana in 1936, and is currently endemic in Togo, Ghana and Nigeria. Over 200 million trees have already been claimed by this disease, which has prompted Ghana to launch the most ambitious and costly eradication effort of any country in the world against a viral plant disease.
Clover yellow mosaic virus (ClYMV) is a plant pathogenic virus in the genus Potexvirus and the virus family Alphaflexiviridae. Its flexuous rod-shaped particles measure about 539 nm in length.
Peanut stunt virus (PSV) is a plant pathogenic virus in the family Bromoviridae. It is a member of the genus Cucumovirus. The members of this genus are positive-stranded RNA viruses with a multipartite genome. The virus particles have an isometric or spherical shape.
Pepper mottle virus (PepMoV) is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae. Like other members of the Potyvirus genus, PepMV is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus is a filamentous particle that measures about 737 nm in length. Isolates of this virus has been completely sequenced and its RNA is 9640 nucleotides long. This virus is transmitted by several species of aphids in a nonpersitant manner and by mechanical inoculation.
White clover mosaic virus (WClMV) is a plant pathogenic virus in the genus Potexvirus and the family Alphaflexiviridae. WClMV is a filamentous, flexuous rod, 480 nm in length and 13 nm wide.
Tobacco etch virus (TEV) is a plant virus in the genus Potyvirus and family Potyviridae. Like other members of the genus Potyvirus, TEV has a monopartite positive-sense, single-stranded RNA genome surrounded by a capsid made from a single viral encoded protein. The virus is a filamentous particle that measures about 730 nm in length. It is transmissible in a non-persistent manner by more than 10 species of aphids including Myzus persicae. It also is easily transmitted by mechanical means but is not known to be transmitted by seeds.
Tradescantia mosaic virus (TZV) is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae. Like other members of the Potyvirus genus, TZV is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus is a filamentous particle that measures about 754 nanometers in length. This virus is transmitted by two species of aphids, Myzus persicae and Rhapalosiphum padi and by mechanical inoculation.
Colias philodice, the common sulphur or clouded sulphur, is a North American butterfly in the family Pieridae, subfamily Coliadinae.
Apium virus Y (ApVY) is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae.
Commelina mosaic virus (CoMV) is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae. Like other members of the Potyvirus genus, CoMV is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus is a filamentous particle that measures about 707-808 nm in length. This virus is transmitted by two species of aphids, Myzus persicae and Aphis gossypii, and by mechanical inoculation.
Trifolium occidentale, the western clover, is a clover plant belonging to the genus Trifolium in the legume family, Fabaceae. Its flowers are white, similar to white clover, with which it has long been confused. This species lives almost exclusively in sand dunes and sea cliffs on the Atlantic coast of Europe, especially Cornwall and the Channel Islands. The species was first described in 1961 by Dr David E Coombe of Cambridge University.
Onion yellow dwarf virus (OYDV) is a plant virus in the genus Potyvirus that has been identified worldwide and mainly infects species of Allium such as onion, garlic, and leek. The virus causes mild to severe leaf malformation, and bulb reduction up to sixty percent has been observed in garlic.
