''Frankliniella schultzei'', the common blossom thrips or cotton thrips, is a species of

thrips Thrips ( order Thysanoptera) are minute (mostly long or less), 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 ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Thripidae The Thripidae are the most speciose family of thrips, with over 290 genera representing just over two thousand species. They can be distinguished from other thrips by a saw-like ovipositor curving downwards, narrow wings with two veins, and anten ...

. It is found in many parts of the world and is an important pest insect in agriculture.

Description

The adult common blossom thrips is a very small insect with a length of between . There are two colour morphs, a dark form and a pale form, each occupying part of the range, with forms of both colours being reported from Egypt, India, Kenya, New Guinea, Puerto Rico, Sudan and Uganda. Identification of thrips species is dependent on the colour, the number and arrangement of the bristles on the body and the details of the comb on the eighth abdominal segment.

Species status

Morphological, biological, molecular and ecological data has demonstrated that the dark and light "forms" of ''F. schultzei'' in Kenya are two distinct species. Genetic analysis of ''F. schultzei'' in Australia shows that there are three highly divergent species of thrips under the taxonomic name ''"F. schultzei"'', and potentially at least six different species globally. ''Frankliniella schultzei'' is therefore a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

, this is important in an agricultural pest because the different species in a complex often have different capacities to damage crops, or transmit viruses (which is true for ''F. schultzei''). Each of the species in a pest species complex has to be investigated separately from the others. Species boundaries also define the limits to the spread of

insecticide resistance Pesticide resistance describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest. Pest species evolve pesticide resistance via natural selection: the most resistant specimens su ...

or any genetically controlled traits that are inherited through sexual reproduction. The host relationships and ecology of each of the species within ''"F. schultzei"'' also need to be assessed separately before the evolution of this complex can be understood.

Distribution and host range

The common blossom thrips has a worldwide distribution, largely in tropical and subtropical environments, but also in protected environments in temperate locations. In Africa it has been reported from Angola, Botswana, Cape Verde, Chad, Congo, Egypt, Ethiopia, Gambia, Ghana, Kenya, Libya, Madagascar, Mauritius, Morocco, Namibia, Niger, Somalia, South Africa, Sudan, Uganda and Zimbabwe; in Asia from Bangladesh, India, Indonesia, Iran, Iraq, Israel, Java, Malaysia, Pakistan and Sri Lanka; in Europe from Belgium, Netherlands, Spain and the United Kingdom; in North America from Florida, Colorado and Hawaii; in Central America and the Caribbean from Barbados, British Virgin Islands, Cuba, Dominican Republic, Haiti, Jamaica and Puerto Rico. in South America from Argentina, Brazil, Colombia, Chile, Guyana, Paraguay, Peru, Uruguay and Venezuela; and in Australasia from Australia, French Polynesia and Papua New Guinea. It is a

polyphagous Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγε ...

species with a wide host range that includes 83 species of plant in 35 different families. In different parts of the world it affects different crops, but these include flowers for cutting,

tomato The tomato is the edible berry of the plant ''Solanum lycopersicum'', commonly known as the tomato plant. The species originated in western South America, Mexico, and Central America. The Mexican Nahuatl word gave rise to the Spanish word ...

lettuce Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...

pepper Pepper or peppers may refer to: Food and spice * Piperaceae or the pepper family, a large family of flowering plant ** Black pepper * ''Capsicum'' or pepper, a genus of flowering plants in the nightshade family Solanaceae ** Bell pepper ** Chili ...

cucumber Cucumber (''Cucumis sativus'') is a widely-cultivated Vine#Horticultural climbing plants, creeping vine plant in the Cucurbitaceae family that bears usually cylindrical Fruit, fruits, which are used as culinary vegetables.

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

peanut The peanut (''Arachis hypogaea''), also known as the groundnut, goober (US), pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible Seed, seeds. It is widely grown in the tropics and subtropics, important to both small ...

spinach Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to central and western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either f ...

pumpkin A pumpkin is a vernacular term for mature winter squash of species and varieties in the genus ''Cucurbita'' that has culinary and cultural significance but no agreed upon botanical or scientific meaning. The term ''pumpkin'' is sometimes use ...

cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...

and

tobacco Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the ...

Ecology

The adult female thrips lays her eggs in the flower tissue of a host plant. At around , the life cycle takes about twelve days; the eggs hatch after four days, there are two larval stages, followed by a non-feeding prepupal and a pupal stage before the adult emerges. Adults survive for about thirteen days. Unfertilized eggs develop into male offspring while fertilized eggs develop into females. In Australia, aggregations of males have been observed on the flowers of ''

Hibiscus rosa-sinensis ''Hibiscus rosa-sinensis'', known colloquially as Chinese hibiscus, China rose, Hawaiian hibiscus, rose mallow and shoeblack plant, is a species of tropical hibiscus, a flowering plant in the Hibisceae Tribe (biology), tribe of the family (biol ...

'' and ''

Gossypium hirsutum ''Gossypium hirsutum'', also known as upland cotton or Mexican cotton, is the most widely planted species of cotton in the world. Globally, about 90% of all cotton production is of cultivars derived from this species. In the United States, the wo ...

''; these were found to attract females so it seems likely that the males were producing a

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

. Besides feeding on plant tissues, the common blossom thrips feeds on pollen grains and on the eggs of mites. The second instar larva consumes more mite eggs than any other stage, and when it supplements its diet in this way, both larval development time and mortality is reduced. Adult female thrips that consume mite eggs increase their fecundity and longevity.

Damage

Both adults and larvae of the common blossom thrips feed on flowers and pollen. The flowers are damaged causing discolouration, distortion and stunting, and may die. Secondary damage is caused by the viruses that can be transmitted between plants. The insect can be a

vector Vector most often refers to: *Euclidean vector, a quantity with a magnitude and a direction *Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematic ...

tomato spotted wilt virus Transmission and lifespan TSWV, which is transmitted by thrips, causes serious losses in economically important crops and it is one of the most economically devastating plant viruses in the world. The circulative propagative transmission of T ...

, which causes a serious disease of groundnuts and other crops.

References

{{Taxonbar, from=Q13561095 Thripidae Agricultural pest insects Taxa named by Filip Trybom