''Aleurocanthus spiniferus'', the citrus spiny whitefly, is an insect native to Asia. It is considered an invasive pest, notably affecting

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

and

tea Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of '' Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of south-western China and nor ...

plants. They are part of the

whitefly 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. Description and taxonomy The A ...

family. ''A. spiniferus'' is indigenous to parts of

tropical Asia Tropical Asia refers to the entirety of the areas in Asia with a tropical climate. These areas are of geographic and economic importance due to their natural resources and biodiversity, which include many species of agricultural value. There are 16 ...

, where it was first discovered in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, soon after which it spread around the world. Wherever it is found, it has become a highly destructive pest. Two populations of ''A. spiniferus'' are known: the citrus spiny whitefly, as well as the tea spiny whitefly, named for the kind of plant they infest.

Description

Adult whiteflies typically lay their eggs in groups on plants (e.g.

), usually on a leaf. Eggs give rise to ''crawlers'' (their first

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

, or developmental stage). These go through two sessile nymphal instars, becoming

pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

(their fourth instar, when they closely resemble related whiteflies), then finally

adult An adult is an animal that has reached full growth. The biological definition of the word means an animal reaching sexual maturity and thus capable of reproduction. In the human context, the term ''adult'' has meanings associated with social an ...

s. The initiation and duration of the life cycle, as well as the number of generations per year is highly dependent on the surrounding climate.Kuwana I, Ishii T. 1927. On ''Prospaltella smithi'' Silv., and ''Cryptognatha'' sp., the enemies of ''Aleurocanthus spiniferus'' Quaintance, imported from Canton, China. ''Review of Applied Entomology'', vol 15: 463. A mild temperature along with high humidity provides an ideal environment for successful growth and development. Kuwana et al. (1927) were able to record about 4 generations per year, with as many as 7 generations under the best laboratory conditions. (This study demonstrated the variability of life-cycle duration.) Varieties have been shown to be exclusive in terms of the plants they lay eggs on. The females of the

-infesting variety only lay eggs on tea plants, not citrus.

Distribution and habitat

The citrus spiny whitefly is indigenous to parts of

, including

where it was first discovered (c. 1903). In the 1920s, Japan conducted a biological control program to control the pest. It had spread to

Jamaica Jamaica is an island country in the Caribbean Sea and the West Indies. At , it is the third-largest island—after Cuba and Hispaniola—of the Greater Antilles and the Caribbean. Jamaica lies about south of Cuba, west of Hispaniola (the is ...

by 1922, and ultimately reached various Pacific Islands (

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

in 1951;

Oahu Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwe ...

in 1974) as well as multiple continents including Europe (in

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

and

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, and the Americas.Kanmiya, K., Ueda, S., Kasai, A., Yamashita, K., Sato, Y., & Yoshiyasu, Y. 2011. Proposal of new specific status for tea-infesting populations of the nominal citrus spiny whitefly ''Aleurocanthus spiniferus'' (Homoptera: Aleyrodidae). ''Zootaxa,'' vol 2797: 25-44. ''A. spiniferus'' can be observed on not only citrus but also on

rose A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivar ...

grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began approximately 8,0 ...

peach The peach (''Prunus persica'') is a deciduous tree first domesticated and Agriculture, cultivated in China. It bears edible juicy fruits with various characteristics, most called peaches and the glossy-skinned, non-fuzzy varieties called necta ...

pear Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus ''Pyrus'' , in the Family (biology), family Rosaceae, bearing the Pome, po ...

, and

guava Guava ( ), also known as the 'guava-pear', is a common tropical fruit cultivated in many tropical and subtropical regions. The common guava '' Psidium guajava'' (lemon guava, apple guava) is a small tree in the myrtle family (Myrtaceae), nativ ...

plants, all of which were observed with the fly in Guam in 1951.

Ecology

''A. spiniferus'' directly damage trees via the ingestion of their

sap Sap is a fluid transported in the xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a s ...

. Infested plants suffer indirect damage from the flies' excretion of honeydew on their leaf surfaces, which promotes the development of

sooty mold Sooty mold (also spelled sooty mould) is a collective term for different Ascomycete fungi, which includes many genera, commonly ''Cladosporium'' and ''Alternaria''. It grows on plants and their fruit, but also environmental objects, like fences, ...

on the leaves, branches, and fruit. This interferes with the plant's health, including its ability to conduct

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

Management

Many whitefly species have become serious pests, especially when first introduced to new geographical regions, where they typically outcompete other pests. This is amplified in the absence of natural enemies, e.g. its

parasitoid wasp Parasitoid wasps are a large group of hymenopteran Superfamily (zoology), superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, ...

, ''E. smithi'', the introduction of which has been successfully employed as a form of

biological pest control Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or ot ...

in response to ''A. spiniferus'' outbreaks. The wasp method was aided by their ability to migrate and adapt to new environments, as well as populate those new areas. Colour preference is another method researchers use to monitor

population dynamics Population dynamics is the type of mathematics used to model and study the size and age composition of populations as dynamical systems. Population dynamics is a branch of mathematical biology, and uses mathematical techniques such as differenti ...

, or for this instance, to control insect numbers in crop protection.Ping, P., Min, T., Yujia, H., Qiang, L., Shanglun, H., Min, D., Xiang, H., & Ying, Z. 2010. Study on the effect and characters of yellow sticky trap sticking ''Aleurocanthus spiniferus'' and ''Empoasca vitis'' in tea garden. ''Southwest China Journal of Agricultural Sciences,'' vol 23: 87-90. Whiteflies have been shown to prefer the colour yellow, therefore methods using this information have been used to create a sticky trap that can aid in controlling these outbreaks. Overall, chemical controls have been attempted in response to the outbreaks such as spraying

pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

s, which can be considered effective but not without detriment. The presumptively high concentrations of pesticides can result in

insecticide resistance Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, ...

, and toxic pesticides could be consumed by humans, e.g. via the drinking of contaminated tea.

References

{{Taxonbar, from=Q2650771 Hemiptera of Asia Whiteflies