''Fiorinia'' is a genus of armored scale insects (family

Diaspididae Diaspididae is the largest family of scale insects with over 2650 described species in around 400 genera. As with all scale insects, the female produces a waxy protective scale beneath which it feeds on its host plant. Diaspidid scales are far mo ...

) with around 70 species. The species are widely distributed around the world. However, the large majority of them are found in southern

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. They infest

woody plant A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposed to Herbaceous plant, herbaceous plants that die back to t ...

s like forest or crop trees,

palm trees The Arecaceae () is a family of perennial, flowering plants in the monocot order Arecales. Their growth form can be climbers, shrubs, tree-like and stemless plants, all commonly known as palms. Those having a tree-like form are colloquially ...

and

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s. Several species are invasive and these are mainly polyphagous species which have spread with the trade of ornamentals. For example, 7 species have been introduced into

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. Type species: ''Fiorinia pellucida'' Targioni Tozzetti, 1868, a synonym of '' Fiorinia fioriniae''.

Distribution

The large majority of species can be found in tropical and subtropical parts of Asia and the

Pacific Islands The Pacific islands are a group of islands in the Pacific Ocean. They are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of several ...

. In other regions, species of ''Fiorinia'' have been frequently reported as being introduced or being intercepted by quarantine. This applies, for example, to all species of ''Fiorinia'' recorded in the United States and in the U.K. Some invasive species like ''F. fioriniae'' or ''F. phantasma'' have reached a wide distribution around the world. Other species like ''F. externa'' are also invasive, but have spread rather slowly.

Description

The species of ''Fiorinia'' are "pupillarial" scales, meaning the scale cover of females is formed by the second-instar female and the adult female remains inside the second-instar

exuviae In biology, exuviae are the remains of an exoskeleton and related structures that are left after ecdysozoans (including insects, crustaceans and arachnids) have molted. The exuviae of an animal can be important to biologists as they can often be ...

. Apart from this feature, the genus is similar morphologically to the genus '' Pseudaulacaspis'', with small differences in the marginal gland spines and the dorsal macroducts. Both genera together with several others form the subtribe Fioriniina. The relationship within this subtribe has been established by a molecular

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis. Since species are often polyphagous and have a similar appearance, it is usually not possible to identify a species reliably by the scale cover and the host plant. For example, in North America '' Fiorinia phantasma'' is very similar externally to '' Fiorinia fioriniae'' and both commonly infest ornamental palms. Therefore, a microscopic examination of morphological details with the help of a slide mount is required for reliable identification, in this case even for routine field surveys. However, for surveys a temporary slide mount may be sufficient. Identification keys are available for some countries like the U.S. and the U.K. The scale cover of ''Fiorinia'' species is elongated and typically has a length of around . The cover of the females often has a brownish colour, that of males is usually white. The individual species have to be identified by morphological details of the adult female and/or the 2nd instar female, including the general shape, the morphology of the posterior end, the pygidium, the antennae, as well as the number and arrangements of macroducts, microducts and gland spines. Like in other scale insects, males resemble tiny wasps and have only one pair of wings.

Biology

The

host range In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasite, parasitic, a mutualism (biology), mutualistic, or a commensalism, commensalist ''guest'' (symbiont). The guest is typically provided with ...

typically includes a number of plant families and several species are highly polyphagous. For example, 54 plant families and 119 plant genera are listed as hosts for ''Fiorinia fioriniae''. The three main groups of host plants are 1)

broad-leaved tree A broad-leaved, broad-leaf, or broadleaf tree is any tree within the diverse botanical group of angiosperms that has flat leaves and produces seeds inside of fruits. It is one of two general types of trees, the other being a conifer, a tree with n ...

s and

s, 2)

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

s and 3)

. The scales usually colonize the underside of the host leaves. Even the polyphagous species have certain preferences, for example ''Fiorinia fioriniae'' is most common on ornamental palm trees and avocado and is regarded as a pest on these. The life cycle of ''Fiorinia'' females involves the egg stage, the crawler stage, the second-instar stage and the adult. Males have two additional instars. Like in other scale insects, only the crawler stage is mobile, moving to other parts of the host plant or migrating longer distances through wind dispersal or on birds. However, the most important means of spread over long distances is by human transport of infested host plants.

Importance

Outbreaks have been reported for invasive ''Fiorinia'' species. These cause yellowing of the infested leaves and occasionally wilting of the host plants, up to plant death. For example, significant damage has been reported on hemlock by ''Fiorinia externa'' or on palm trees by ''Fiorinia phantasma''. Several species are regarded as agricultural or forest pests. These include: * '' Fiorinia externa'', the elongate hemlock scale, a species native to eastern Asia that has been accidentally introduced into eastern North America, where it infests hemlock trees (''

Tsuga ''Tsuga'' (, from Japanese (), the name of '' Tsuga sieboldii'') is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The English-language common name "hemlock" arose from a perceived similarity in the smell of it ...

'') and other conifers. * '' Fiorinia fioriniae'', the palm fiorinia scale, a widely distributed polyphagous pest of palm trees and ornamentals. * '' Fiorinia phantasma'', the phantasma scale, a pest of palm trees, other ornamentals and some fruit trees which is found in various regions. * '' Fiorinia theae'', the tea scale, a widely distributed and polyphagous species which infests, apart from tea, various wild and cultivated shrubs and trees like citrus and

holly ''Ilex'' () or holly is a genus of over 570 species of flowering plants in the family Aquifoliaceae, and the only living genus in that family. ''Ilex'' has the most species of any woody dioecious angiosperm genus. The species are evergreen o ...

(''Ilex'') species.

List of species

The genus includes around 70 species. The following list includes the more common species, based on the number of articles cited by ScaleNet:

References

{{Taxonbar, from1=Q10495627 Diaspidini Sternorrhyncha genera Taxa described in 1869