''Aleurocanthus woglumi'' is a species of whitefly in the family

Aleyrodidae 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 ...

. It is a pest of

citrus ''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as Orange (fruit), oranges, Lemon, lemons, grapefruits, pomelos, and lim ...

crops, and is commonly known as the citrus blackfly because of its slate-blue colour. It originated in Asia, but has spread to other parts of the world.Dietz HF, Zetek J. 1920. The blackfly of citrus and other subtropical plants. USDA Bulletin 885: 1-55. The

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

wasps, ''

Encarsia perplexa ''Encarsia perplexa'' is a tiny parasitic wasp, a parasitoid of the citrus blackfly, ''Aleurocanthus woglumi'', which is a global pest of citrus trees. It was originally misidentified as ''Encarsia opulenta'', but was recorded as a new species ...

'' and '' Amitus hesperidum'' can help control the pest.

Distribution

This species is native to India, but also occurs in other parts of Asia, Africa, Central and South America, Mexico, the West Indies, Jamaica, and the United States (Florida, Texas, and Hawaii).http://hawaii.gov/hdoa/pi/ppc/npa-1/npa99-03_citrusbf.pdf

Host species

The citrus blackfly is found on over 300 host plant species, but citrus trees such as

lemon The lemon (''Citrus limon'') is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China. The tree's ellipsoidal yellow fruit is used for culin ...

orange Orange most often refers to: *Orange (fruit), the fruit of the tree species '' Citrus'' × ''sinensis'' ** Orange blossom, its fragrant flower *Orange (colour), from the color of an orange, occurs between red and yellow in the visible spectrum * ...

and

pomelo The pomelo ( ), ''Citrus maxima'', is the largest citrus fruit from the family Rutaceae and the principal ancestor of the grapefruit. It is a natural, non-hybrid, citrus fruit, native to Southeast Asia. Similar in taste to a sweet grapefr ...

are most heavily infested. Noncitrus trees and shrubs, when they grow by themselves, are not normally attacked by this insect, but they may be when they grow close to heavy infestations on citrus. In Hawaii, such trees as mango, avocado, pink tecoma, and surinam cherry have hosted colonies.

Lifecycle

The female blackfly lays batches of

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

in a spiral pattern on the undersides of leaves. The eggs are golden-brown, but darken before hatching, which happens in seven to 10 days.Dowell RV, Cherry RH, Fitzpatrick GE, Reinert JA, Knapp JL. 1981. Biology, plant-insect relations, and control of the citrus blackfly. Florida Agricultural Experiment Station Bulletin 818: 1-48. The

nymph A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ty ...

moults three times. The first

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

is a brown, elongated oval shape, about long with two transparent filaments curling back over the body. The second instar is a darker brown and has short spines on its body. It measures about long. The third instar is glossy black with many stout spines and measures about long by wide. The larval stages last three to 9 weeks. The

pupa A pupa ( la, pupa, "doll"; plural: ''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 ...

is ovate and black, with short bristles and a marginal fringe of waxy secretion. The adult, when it first emerges, has a pale-yellow head, whitish legs and reddish-brown eyes. Soon afterwards, it darkens, developing a fine covering of waxy powder which gives it a slate-blue appearance. The wings are angled and held in a tented fashion. The whole lifecycle takes from 45 to 130 days, depending largely on the temperature.

Damage

The principal harm done by the citrus blackfly is the sucking of the tree's

sap Sap is a fluid transported in 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 separa ...

, which deprives it of both water and nutrients. The excretion of honeydew coats the leaf surfaces and encourages the growth 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, ...

. This can severely impair both leaf respiration and

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

. The combination of all these factors causes a decline in the health and vigour of the tree and a reduction in fruit yield.

Management

The citrus blackfly has a number of natural enemies. The most effective agents for controlling it in Florida are the parasitic wasps, ''

'' and '' Amitus hesperidum''. The former has a lower rate of reproduction than does ''A. hesperidum'', but is better able to search out suitable hosts. The latter is well synchronized with its host, as adult female wasps are ready to lay their eggs at about the same time as suitable larval stages of the blackfly are present.Nguyen Ru, Brasil JR, Poucher C. 1983. Population density of the citrus blackfly, Aleurocanthus woglumi Ashby (Homoptera: Aleyrodidae), and its parasites in urban Florida in 1979-81. Environmental Entomology 12: 878-884. These species have been used in

biological control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...

of the pest. For example, both species were introduced into Hawaii in 1999 after discovery of the presence of the citrus blackfly the previous year. Both wasps have succeeded in establishing themselves and are helping to reduce the damage done by the pest. The use of

insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...

s may help to control infestations temporarily, but this is not advised because of the adverse effects on the environment and any existing predators. The application of an oil emulsion may be effective and less toxic. A sufficiency of water and appropriate applications of

fertiliser A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

will encourage growth and minimise damage.

References

External links

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{{Taxonbar, from=Q1645537 Whiteflies Agricultural pest insects Citrus pests Insects described in 1915