|Thrips tabaci (left); Frankliniella occidentalis (right)|
Thrips tabaci is a species of very small insect in the genus Thrips in the order Thysanoptera. It is commonly known as the onion thrips, the potato thrips, the tobacco thrips or the cotton seedling thrips.It is an agricultural pest that can damage crops of onions and other plants, and it can additionally act as a vector for plant viruses.
In some populations, nearly all onion thrips are female, and males are very rare. 1 to 1.3 mm (0.04 to 0.05 in) long. The body is some shade of yellow, yellowish-brown or brown; the antennae have seven segments, the wings are well-developed and females have an ovipositor at the tip of the abdomen.The adult onion thrips is some
The onion thrips is thought to have originated in the Mediterranean region but is now found on all continents except Antarctica.It infests a wide range of host plants that include onion, leek and garlic, brassicaceous plants such as cabbage, cauliflower and broccoli, asparagus, sugarbeet, melon, pumpkin, marrow and cucumber, strawberry, potato, tobacco, cotton and many fruiting and ornamental plants. Onion thrips was the first vector identified for tomato spotted wilt virus, being reported in 1927. There are now some identified populations of onion thrips that are not able to transmit tomato spotted wilt virus, possibly due to genetic spread in the global population.
The female inserts her saw-like ovipositor into plant tissues and lays her eggs under the epidermis. The eggs are white at first, turning orange later, and hatch in four to five days. The larvae are white or yellowish and suck sap from the plant tissues. Two larval stages lasting about nine days in total are followed by the non-feeding prepupal and pupal stages which last four to seven days in total. The adult survives for two or three weeks during which time the females lay about eighty eggs. Most of the eggs are unfertilised and produced by parthenogenesis. In Hawaii, only about one in a thousand individuals is male,and in this location, it breeds throughout the year. In cooler climates it overwinters in plant debris and becomes active again in spring.
In populations from different areas, the ratio of males to females varies. A male to female ratio as high as 1 male to 2 females has been recorded from Central Spain, and 1 male to 6 females in Colorado. In contrast, counts as low as 1 male to 300 females have been recorded from Sudan, and in Hawaii a collection of over 5000 specimens held only 5 males in total. Some collections over the years from France, Japan, Taiwan and India have had no reported males at all. One study of the literature published in 1990 suggested a correlation between longitude and male population number, with the higher male counts occurring in the Western hemisphere.
The onion thrips is the most serious insect pest attacking onion crops in the tropics. The thrips rasp and pierce the surface of the plant with their mouthparts, mostly choosing young plant growth. They then add digestive juices and suck up the fluids that seep from the wounds. As the plant part grows, so do the damaged regions, leaving silvery streaks. The more thrips that are present, the greater the area of plant damaged, reducing the area of foliage available for photosynthesis. At the same time, more water is transpired and pathogens can find a way to gain entry. In severely damaged plants, leaves may wither and the whole plant may appear silvery; the crop ripens prematurely but the yield is greatly reduced.
The onion thrips is a vector of certain plant viruses, including iris yellow spot tospovirus, strawberry necrotic shock virus, tobacco streak virus and tomato spotted wilt virus.It is also a vector of Alternaria porri , which causes the fungal disease known as purple blotch.
Whiteflies are Hemipterans that typically feed on the undersides of plant leaves. They comprise the family Aleyrodidae, the only family in the superfamily Aleyrodoidea. More than 1550 species have been described.
Thrips are minute, slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are predators. Entomologists have described approximately 6,000 species. They fly only weakly and their feathery wings are unsuitable for conventional flight; instead, thrips exploit an unusual mechanism, clap and fling, to create lift using an unsteady circulation pattern with transient vortices near the wings.
The silverleaf whitefly is one of several species of whitefly that are currently important agricultural pests. A review in 2011 concluded that the silverleaf whitefly is actually a species complex containing at least 40 morphologically indistinguishable species.
Meloidogyne arenaria is a species of plant pathogenic nematodes. This nematode is also known as the peanut root knot nematode. The word "Meloidogyne" is derived from two Greek words that mean "apple-shaped" and "female". The peanut root knot nematode, M. arenaria is one of the "major" Meloidogyne species because of its worldwide economic importance. M. arenaria is a predominant nematode species in the United States attacking peanut in Alabama, Florida, Georgia, and Texas. The most damaging nematode species for peanut in the USA is M. arenaria race 1 and losses can exceed 50% in severely infested fields. Among the several Meloidogyne species that have been characterized, M. arenaria is the most variable both morphologically and cytologically. In 1949, two races of this nematode had been identified, race 1 which reproduces on peanut and race 2 which cannot do so. However, in a recent study, three races were described. López-Pérez et al (2011) had also studied populations of M. arenaria race 2, which reproduces on tomato plants carrying the Mi gene and race 3, which reproduces on both resistant pepper and tomato.
Xiphinema americanum, the American dagger nematode, is a species of plant pathogenic nematodes. It is one of many species that belongs to the genus Xiphinema. It was first described by N. A. Cobb in 1913, who found it on both sides of the United States on the roots of grass, corn, and citrus trees. Not only is Xiphinema americanum known to vector plant viruses, but also X. americanum has been referred to as "the most destructive plant parasitic nematode in America", and one of the four major nematode pests in the Southeastern United States.
Impatiens necrotic spot orthotospovirus(INSV) is a plant pathogenic virus of the order Bunyavirales. It was originally believed to be another strain of Tomato spotted wilt virus, but genetic investigations revealed them to be separate viruses. It is a negative-strand RNA virus which has a tripartite genome. It is largely spread by the insect vector of the western flower thrips. The virus infects more than 648 species of plants including important horticultural and agricultural species such as fuchsia, tomato, orchids, and lettuce. As the name implies, the main symptom on plants is necrotic spots that appear on the leaves. The INSV virus infects by injecting the RNA the virus contains into the cell which then starts using the cell resources to transcribe what the virus RNA states. Viral infection can often result in the death of the plant. The disease is mainly controlled by the elimination of the western flower thrip vector and by destroying any infected plant material.
Tobacco streak virus (TSV) is a plant pathogenic virus of the family Bromoviridae, in the genus Ilarvirus. It has a wide host range, with at least 200 susceptible species. TSV is generally more problematic in the tropics or warmer climates. TSV does not generally lead to epidemics, with the exception of sunflowers in India and Australia, and peanuts in India.
The western flower thrips [Frankliniella occidentalis (Pergande)] is an invasive pest insect in agriculture. This species of thrips is native to the Southwestern United States but has spread to other continents, including Europe, Australia, and South America via transport of infested plant material.
Orthotospovirus is a genus of negative-strand RNA viruses, in the family Tospoviridae of the order Bunyavirales, which infects plants. Tospoviruses take their name from the species Tomato spotted wilt orthotospovirus (TSWV) which was discovered in Australia in 1919. TSWV remained the only member of the family until the early 1990s when genetic characterisation of plant viruses became more common. There are now at least twenty species in the genus with more being discovered on a regular basis. Member viruses infect over eight hundred plant species from 82 different families.
The chilli thrips or yellow tea thrips, Scirtothrips dorsalis Hood, is an extremely successful invasive species of pest-thrips which has expanded rapidly from Asia over the last twenty years, and is gradually achieving a global distribution. It has most recently been reported in St. Vincent (2004) Florida (2005), Texas (2006), and Puerto Rico (2007). It is a pest of economic significance with a broad host range, with prominent pest reports on crops including pepper, mango, citrus, strawberry, grapes, cotton, tea, peanuts, blueberry, and roses. Chilli thrips appear to feed preferentially on new growth, and infested plants usually develop characteristic wrinkled leaves, with distinctive brown scarring along the veins of leaves, the buds of flowers, and the calyx of fruit. Feeding damage can reduce the sale value of crops produced, and in sufficient numbers, kill plants already aggravated by environmental stress. This thrips has also been implicated in the transmission of three tospoviruses, but there is some controversy over its efficiency as a vector.
Myzus persicae, known as the green peach aphid, greenfly, or the peach-potato aphid, is a small green aphid belonging to the order Hemiptera. It is the most significant aphid pest of peach trees, causing decreased growth, shrivelling of the leaves and the death of various tissues. It also acts as a vector for the transport of plant viruses such as cucumber mosaic virus (CMV), potato virus Y (PVY) and tobacco etch virus (TEV). Potato virus Y and potato leafroll virus can be passed to members of the nightshade/potato family (Solanaceae), and various mosaic viruses to many other food crops.
Thrips palmi is an insect from the genus Thrips in the order Thysanoptera. It is known commonly as the melon thrips.
The Thripinae are a subfamily of thrips, insects of the order Thysanoptera. The Thripinae belong to the common thrips family Thripidae and include around 1,400 species in 150 genera. A 2012 molecular phylogeny found that the Thripinae was paraphyletic; further work will be needed to clarify the relationships within the group.
Frankliniella tritici, the eastern flower thrips, is a species of thrips in the genus Frankliniella. F. tritici inhabits blossom, such as dandelion flowers. They can directly damage plants, grasses and trees, in addition to commercial crops, and as a vector for tospoviruses, a form of plant virus, it particularly affects small fruit production in the United States, including strawberries, grapes, blueberries and blackberries. It can also affect alfalfa, oats, beans and asparagus crops. The species features strap-like wings edged with long hairs, a design which increases aerodynamic efficiency in very small arthropods; the reduced drag means the insect uses less energy. They extract nutrients directly from individual plant cells, and may also digest cells of fungi in the leaf litter.
Dicyphus hesperus is a species of true bug in the family Miridae. It is a generalist predator of other insects and also feeds on plant tissues. It is native to North America and has been used there in biological control of agricultural pests, especially whitefly on tomatoes.
Thrips simplex is a species of insect in the genus Thrips in the order Thysanoptera. It is commonly known as the gladiolus thrips and infests gladiolus plants as well as various other monocotyledonous plants such as lilies, irises and freesias.
Frankliniella schultzei, the common blossom thrips or cotton thrips, is a species of thrips in the family Thripidae. It is found in many parts of the world and is an important pest insect in agriculture.
Heliothrips haemorrhoidalis is a species of thrips in the family Thripidae. It is most commonly known as the greenhouse thrips, the glasshouse thrip or black tea thrips. This species of thrips was first described in 1833 by Bouché in Berlin, Germany. H. haemorrhoidalis also has many synonyms depending on where they were described from such as: H. adonidum Haliday, H. semiaureus Girault, H. abdominalis Reuter, H. angustior Priesner, H. ceylonicus Schultz, Dinurothrips rufiventris Girault. In New Zealand, H. haemorrhoidalis is one of the four species belonging to the subfamily Panchaetothripinae.
Tomato spotted wilt orthotospovirus (TSWV) is a spherical negative-sense RNA virus that has a diameter between 80-110 nanometers.