The silverleaf whitefly (''Bemisia tabaci'', also informally referred to as the sweet potato whitefly) is one of several species of

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 ...

that are currently important

agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...

pests PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...

. A review in 2011 concluded that the silverleaf whitefly is actually 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 ...

containing at least 40 morphologically indistinguishable species. The silverleaf whitefly thrives worldwide in tropical, subtropical, and less predominately in temperate habitats. Cold temperatures kill both the adults and the nymphs of the species. The silverleaf whitefly can be confused with other insects such as the common fruitfly, but with close inspection, the whitefly is slightly smaller and has a distinct wing color that helps to differentiate it from other insects. While the silverleaf whitefly had been known in the United States since 1896, in the mid-1980s an aggressive strain appeared in

poinsettia The poinsettia ( or ) (''Euphorbia pulcherrima'') is a commercially important flowering plant species of the diverse spurge family Euphorbiaceae. Indigenous to Mexico and Central America, the poinsettia was first described by Europeans in 183 ...

crops in

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

. For convenience that strain was referred to as (biotype B), to distinguish it from the milder infestation of the earlier known . Less than a year after its identification, strain B was found to have moved to

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 ...

es, and other fruit and vegetable crops. Within five years, the silverleaf whitefly had caused over $100 million in damage to agriculture in Texas and in California.

Anatomy and life cycle

Female ''B. tabaci'' will lay 50 to 400 eggs ranging from on the under part of leaves. Female whiteflies are

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectiv ...

and emerge from fertilized eggs whereas male whiteflies are

haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...

and emerge from unfertilized eggs. Eggs are laid in groups, being small in size with dimensions of wide and in height. Eggs are initially whitish in color and change to a brown color near hatching, within 5 to 7 days. After hatching, the whitefly nymph develops through four

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 ...

stages.

Silverleaf Whitefly (Bemisia tabaci) adult

The first

, commonly called a crawler, is the only mobile nymphal stage. The first instar nymph can grow to about and is greenish in color and flat in body structure. The mobile nymph walks to find a suitable area on the leaf with adequate nutrients and molts into an immobile stage. The next three

s remain in place for 40–50 days, until molting into an adult. Silver

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

, or shed skins are left on the leaves. The immobile instars appear opaquely white. Nymphs feed by stabbing into the plant with their mouth-parts and sucking up plant juices. After the fourth instar, the nymph transforms into a pupal stage where the eyes become a deep red color, the body color becomes yellow, and the body structure thickens. This is not a true pupal stage, as is found in the

Endopterygota Endopterygota (from Ancient Greek ''endon'' 'inner' + ''pterón'' 'wing' + New Latin ''-ota'' 'having'), also known as Holometabola, is a superorder of insects within the infraclass Neoptera that go through distinctive larval, pupal, and a ...

, but is similar in function. Adult whiteflies are approximately four times the size of the egg, with light yellow bodies and white wings, which is attributed by the secretion of wax across its wings and body. Adult silverleaf whiteflies can reach up to in length. While feeding or resting the whitefly adult folds its wings tent-like over its body.

Distribution

Native/original community

Research indicates that the silverleaf whitefly likely came from India. Since the whitefly is predominately associated with areas exhibiting

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

subtropical The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...

climates, the focus shifts to how these insects attained access to crops in habitats with

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...

climates. One

hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...

suggests that the transfer of decorative plants from tropical regions may have aided in the spread of the silverleaf whiteflies to temperate environments. The ability of the whitefly to adapt to various plants facilitates the spread of dangerous plant viruses, which these insects are notorious for transmitting. Plants which are affected by the whitefly include:

es,

squash Squash may refer to: Sports * Squash (sport), the high-speed racquet sport also known as squash racquets * Squash (professional wrestling), an extremely one-sided match in professional wrestling * Squash tennis, a game similar to squash but pla ...

cucumber Cucumber (''Cucumis sativus'') is a widely-cultivated creeping vine plant in the Cucurbitaceae family that bears usually cylindrical fruits, which are used as culinary vegetables.eggplant Eggplant ( US, Canada), aubergine ( UK, Ireland) or brinjal (Indian subcontinent, Singapore, Malaysia, South Africa) is a plant species in the nightshade family Solanaceae. ''Solanum melongena'' is grown worldwide for its edible fruit. Mo ...

okra Okra or Okro (, ), ''Abelmoschus esculentus'', known in many English-speaking countries as ladies' fingers or ochro, is a flowering plant in the mallow family. It has edible green seed pods. The geographical origin of okra is disputed, with su ...

beans A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes thr ...

, and

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 pe ...

. Other common plant damages of whitefly include: removing plant sap, breakdown of the leaves of the plant, and leaf shedding.

Introduced range

The silverleaf whitefly is an invasive agricultural pest in many locations around the world, including in Florida and in California.

Commercial impact

The silverleaf whitefly is considered an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

as well as

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

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

, and several European countries. It was classified as an agricultural pest in

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders wi ...

around 1889 and had a significant impact on tobacco crops there. The first silverleaf whitefly was found in the United States in 1897 on a crop of sweet potatoes. This tiny insect causes damage to plants through feeding and transmitting plant diseases. The silverleaf whitefly feeds on its host plants by piercing the

phloem Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is c ...

or lower leaf surfaces with its mouth and removing nutrients. Affected areas of the plant may develop

chlorotic In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to ...

spots, whither, or drop leaves. Whiteflies also produce a sticky substance called honeydew, which is left behind on the host. Honeydew can induce 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, ...

s, which can then reduce the plants ability to absorb light. This results in slower growth, lower yield, and poor quality plants. It also requires that crops be thoroughly washed after harvesting, which raises processing costs for the grower. The silverleaf whitefly is also a notorious vector for plant disease. It has transmitted gemniviruses including lettuce infectious yellows virus, tomato yellow leaf curl virus, and

African cassava mosaic virus ''African cassava mosaic virus'' (ACMV, ICTV approved acronym) is a plant pathogenic virus of the family '' Geminiviridae'' that may cause either a mosaic appearance to plant leaves, or chlorosis, a loss of chlorophyll. In ''Manihot esculenta'' ...

for years and over many continents and is now a vector for

cassava brown streak virus disease Cassava brown streak virus disease (CBSD) is a damaging disease of cassava plants, and is especially troublesome in East Africa. It was first identified in 1936 in Tanzania, and has spread to other coastal areas of East Africa, from Kenya to Moza ...

. ''Bemisia tabaci'' became a serious issue in crops across the southwestern United States and

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

in the 1980s. Scientists speculate that this pest was introduced via infested ornamental plants brought into the United States at this time. Florida's poinsettia greenhouses were crippled by the pest beginning in 1986, and by 1991, the infestation had spread through Georgia, Louisiana, Texas, New Mexico, and Arizona to plague growers in California. California produces approximately 90% of the United States’ winter vegetable crop, and has incurred an estimated $500 million in crop damage due to silverleaf whitefly populations. Across the agricultural industry, this pest is thought to cost the state $774 million in private sector plant sales, 12,540 jobs, and $112.5 million in personal income. On a national scale, the United States has suffered crop and ornamental plant damages in excess of $1 billion. This species of whitefly is a particularly devastating pest because it feeds on over 500 plant species. Common hosts are agricultural crops including tomatoes, squash, broccoli, cauliflower, cabbage, melons, cotton, carrots, sweet potato, cucumber, and pumpkin, and ornamental plants such as

, crepe myrtle,

garden roses Garden roses are predominantly hybrid roses that are grown as ornamental plants in private or public gardens. They are one of the most popular and widely cultivated groups of flowering plants, especially in temperate climates. An enormous number ...

lantana ''Lantana'' () is a genus of about 150 species of perennial flowering plants in the verbena family, Verbenaceae. They are native to tropical regions of the Americas and Africa but exist as an introduced species in numerous areas, especially in ...

, and

lilies ''Lilium'' () is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much of the world. M ...

. It can cause specific damage to certain host plants, like "silverleaf" on squash, irregular ripening of tomatoes, whitestalk in broccoli and cauliflower, white stem in poinsettia, and light root in carrots.Service, A. R. National Invasive Species Information Center
Silverleaf Whitefly
''United States Department of Agriculture''.

Nuclear receptors

''B. tabaci'' like all arthropods has

ecdysone receptor The ecdysone receptor is a nuclear receptor found in arthropods, where it controls development and contributes to other processes such as reproduction. The receptor is a non-covalent heterodimer of two proteins, the EcR protein and ultraspiracle ...

s (EcRs) which may be useful for

insecticide development Pesticides are substances that are meant to pest control, control pest (organism), pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microb ...

. Carmichael ''et al.'', 2005 presents the X-ray crystal structure for the 1Z5X

ligand-binding domain In the field of molecular biology, nuclear receptors are a class of proteins responsible for sensing steroids, thyroid hormones, vitamins, and certain other molecules. These receptors work with other proteins to regulate the expression of speci ...

of the ''B. tabaci'' EcR.

Integrated pest management

Multiple methods of control can be used to combat these prevalent agricultural pests. Some major control methods include, application of oils, use of natural enemies such as

Aphelinidae The Aphelinidae are a moderate-sized family of tiny parasitic wasps, with about 1100 described species in some 28 genera. These minute insects are challenging to study, as they deteriorate rapidly after death unless extreme care is taken (e.g., ...

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

s, employment of trap crops, release of insect growth regulators, and implementation of traps. Most of these control tools have a minimal effect on plant and soil properties. Scientists are currently focusing on targeting the whitefly through mechanisms that do not cause pollution or contamination (i.e., mechanisms other than insecticides). It is important to be able to reduce the number of ''B. tabaci'' individuals that settle on plants to decrease plant damages such as those caused by viral transmissions. This can be accomplished by reducing settling, decreasing

oviposition The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...

, and abating population development.

Biological controls

Classical biological control has been the best long-term, sustainable solution to controlling these exotic pests. However, success of this method can be unpredictable. Entomologists with the U.S. Arid-Land Agricultural Research Center identified the most common causes of death of the whitefly as predation by other insects, parasitism, and weather induced dislodgement.United States Department of Agriculture
Beyond Insecticides: Improved Methods of Whitefly Control
Retrieved March 15, 2011. They emphasize the importance of exploiting the use of natural predators and have identified predators by the use of enzyme-linked immune sorbent assay (

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presen ...

). It was found that the use of the biological controls and insect growth regulators produces a higher predator-to-prey ratio.McGinnis, L. (April 5, 2006
Alternate Methods of Whitefly Control
usda.gov Insect growth regulators, such as buprofezin and

pyriproxyfen Pyriproxyfen is a pesticide which is found to be effective against a variety of insects. It was introduced to the US in 1996, to protect cotton crops against whitefly. It has also been found useful for protecting other crops. It is also used as a ...

, conserve natural predators compared to conventional

insecticides 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 t ...

, which can indiscriminately kill both predator and pest populations.

Natural enemies

Predators,

s, and

pathogens In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...

specific to whiteflies can keep populations under control. Species in eight arthropod orders are known to be predators of ''B. tabaci.'' These include members of the families

Phytoseiidae The Phytoseiidae are a family of mites which feed on thrips and other mite species. They are often used as a biological control agent for managing mite pests. Because of their usefulness as biological control agents, interest in Phytoseiidae has ...

Coccinellidae Coccinellidae () is a widespread family of small beetles ranging in size from . They are commonly known as ladybugs in North America and ladybirds in Great Britain. Some entomologists prefer the names ladybird beetles or lady beetles as they ...

, Syrphidae,

Anthocoridae Anthocoridae is a family of bugs, commonly called minute pirate bugs or flower bugs. Worldwide there are 500-600 species. Description Anthocoridae are 1.5–5 mm long and have soft, elongated oval, flat bodies, often patterned in black an ...

Nabidae The insect family Nabidae contains the damsel bugs. There are over 500 species in 20 genera. They are soft-bodied, elongate, winged terrestrial predators. Many damsel bugs catch and hold prey with their forelegs, similar to mantids. They are c ...

, and Miridae,

Chrysopidae Green lacewings are insects in the large family Chrysopidae of the order Neuroptera. There are about 85 genera and (differing between sources) 1,300–2,000 species in this widespread group. Members of the genera ''Chrysopa'' and ''Chrysoper ...

and

Coniopterygidae The dustywings, Coniopterygidae, are a family of Pterygota (winged insects) of the net-winged insect order ( Neuroptera). About 460 living species are known.Engel & Grimaldi (2007) These tiny insects can usually be determined to genus with a ha ...

.Hoddle, Mark S. (1999)
The Biology and Management of the Silverleaf Whitefly, ''Bemisia argentifolii'' Bellows and Perring (Homoptera: Aleyrodidae) on Greenhouse Grown Ornamentals
biocontrol.ucr.edu There are currently four species of predators that are commercially available for control of ''B. tabaci:'' '' Delphastus pusillus,'' '' Macrolophus caliginosus,'' '' Chrysoperla carnea,'' and '' C. rufilabris''. ''D. pusillus'' is a species of small, shiny, black beetle which sucks out the contents of the silverleaf whitefly by piercing its exoskeleton. Adult and larval stages of this beetle feed on all life stages of the pest. ''C. rufilabris'' is only able to feed on the immature stages or the larval stages of ''B. tabaci''. Another natural enemy of the whitefly are

parasitoids In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasi ...

, which kill their host once their development has been completed. Parasitoids in the families Platygasteridae,

, and

Eulophidae The Eulophidae are a large family of hymenopteran insects, with over 4,300 described species in some 300 genera. The family includes the genus ''Elasmus'', which used to be treated as a separate family, "Elasmidae", and is now treated as a subf ...

are known to attack whiteflies. Establishment of several

Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by thei ...

species of '' Eretmocerus'' wasps has been attempted in the Western United States to control ''B. tabaci''. However, differences in climate preference by these wasps reduced their effect. The best studied of these whitefly parasitoids are ''

Encarsia formosa ''Encarsia formosa'' is a species of chalcidoid wasp and a well known parasitoid of greenhouse whitefly, one of the first to be used commercially for biological pest control, from the 1920s. They can use at least 15 species of whitefly as a hos ...

'' and '' Eretmocerus eremicus'', both of which are commercially available. The ''Encarsia formosa'' "Beltsville Strain", however, has been unsuccessful in control ''B. tabaci'' biotype B in commercial greenhouses; it is only able to control the species in small experimental greenhouses. The species ''Encarsia formosa'' works much better at controlling the whitefly species ''

Trialeurodes vaporariorum ''Trialeurodes vaporariorum'', commonly known as the glasshouse whitefly or greenhouse whitefly, is an insect that inhabits the world's temperate regions. Like various other whiteflies, it is a primary insect pest of many fruit, vegetable and o ...

'' than it does ''B. tabaci''. ''Eretmocerus sp.'' has been found more successful at ''B. tabaci'' than the ''E. formosa'' "Beltsville Strain". The wasps are faster at searching for patches of host nymphs are consistent at controlling the population. A variable release strategy of parasitoids has been found successfully able to control populations of ''B. tabaci''. This was done by releasing six female parasitoids per week for the first half of the growing season, and only one female per week for the remaining of the season. This improved the effectiveness of the parasitoid wasps by ensuring they were continuously available to attack the pests, but in numbers that reflected the shrinking population of pests. If natural enemies are not able to control the pest population at low levels due to a significant increase in pest, an insecticide compatible with the biological control agent could be used to assist in reducing the pest population to low levels again. Another natural mechanism of controlling the population of ''B. tabaci'' is the use of fungal pathogens. The most commonly known pathogens to the whitefly pest are ''

Paecilomyces fumosoroseus ''Isaria fumosorosea'' is an entomopathogenic fungus, formerly known as ''Paecilomyces fumosoroseus''. It shows promise as a biological pesticide with an extensive host range. Life cycle When a conidium or blastospore of ''Isaria fumosorosea ...

'', '' Aschersonia aleyrodis'', '' Verticillium lecanii'', and ''

Beauveria bassiana ''Beauveria bassiana'' is a fungus that grows naturally in soils throughout the world and acts as a parasite on various arthropod species, causing white muscardine disease; it thus belongs to the entomopathogenic fungi. It is used as a biologic ...

''. When spore solutions of ''V. lecanii'' are sprayed on eggs of ''B. tabaci'' approximately 89% to 90% of these eggs are killed. Some strains of whitefly have developed resistance to its fungal pathogens including ''V. lecanii''. Beauveria bassiana

''B. bassiana'' is only an effective biological control agent in conditions of low temperatures (maximum of ) and a humidity level greater than 96%. Not enough studies have been conducted to show the productiveness of fungal pathogen in the real world environment. Much of the success of this biological control on ''B. tabaci'' has been conducted in the laboratory. However, it can be concluded though that when the fungal pathogen is combined with an insecticide, the synergistic effect of the two will induce a higher mortality rate of the whitefly. ''P. fumosoroseus'' has a broad host range but can attack silverleaf whiteflies at a variety of life stages and these include eggs, nymphs, pupae, and adults stages. On the other hand, ''A. aleyrodis'' only infects and destroys nymphs and pupae.

Chemical controls

Natural oils

Natural oils are another important tool in the control of ''B. tabaci.'' Currently, the most effective oil in the market is the ultra-fine oil, which is a paraffinic oil product that reduces the settlement of the adult flies, decreases

, and abates the transmission of the tomato yellow leaf curl virus. The effect of ultra-fine oil can be strengthened through the combination with oils such as

limonene Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels. The -isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring a ...

citronellal Citronellal or rhodinal ( C10 H18 O) is a mono terpenoid aldehyde, the main component in the mixture of terpenoid chemical compounds that give citronella oil its distinctive lemon scent. Citronellal is a main isolate in distilled oils from the ...

. Olive oil is also highly effective in controlling the number of whiteflies. Other natural oils such as cottonseed, castor, peanut, soybean, and sunflower can be effective. Peanut oil was the most effective out of this group in reducing the population. All of these oils cause direct mortality to immature life stages of the silverleaf whitefly on contact and reduce settling and ovipositon by adults when sprayed on plant leaves. The oil extracted from the seeds of sugar apple has also been found effective against the whitefly. This oil causes the silverleaf whitefly nymph to shrink in size and therefore detach from the tomato plant, leading to starvation. Sugar apple seed oil is not

phytotoxic Phytotoxins are substances that are poisonous or toxic to the growth of plants. Phytotoxic substances may result from human activity, as with herbicides, or they may be produced by plants, by microorganisms, or by naturally occurring chemical react ...

to tomato plants of any concentrations and reduces the survival rate of the pest.

Insect growth regulators

Insecticides can be costly, and have an increasing risk of resistance by whiteflies. However, the

insect growth regulator An insect growth regulator (IGR) is a substance (chemical) that inhibits the life cycle of an insect. IGRs are typically used as insecticides to control populations of harmful insect pests such as cockroaches and fleas. Advantages Many IGRs are l ...

has been found successful in reducing whitefly populations on c

urbit Urbit is a decentralized personal server platform. The platform seeks to deconstruct the client-server model in favour of a federated network of personal servers in a peer-to-peer network with a consistent digital identity. Overview The Urb ...

plants including zucchini squash, cucumber, and pumpkin. This hormone is a juvenile hormone analogue, which affects hormonal balance and

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

in immature insects, and causes deformation and death during molting and

pupation 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 thei ...

. This insect growth regulator does not kill adult whiteflies, and has low toxicity to mammals, fish, birds and bumblebees.

Mechanical controls

Man-made traps and covers

Traps offer a pesticide free method of control of ''B. tabaci.'' The Light-Emitting Diode Equipped CC trap (LED-CC) was developed by plant

physiologist Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemica ...

Chang-Chi Chu and Thomas Henneberry.Elstein, David (May 30, 2002)
New Trap To Control Silverleaf Whiteflies
usda.gov. Originally, the trap was used to monitor population of silverleaf whitefly populations, but as the trap was improved it was used in control programs to limit whitefly pest populations. The trap itself includes a green LED light that attracts and traps the whiteflies. The LED device works best at night, and is inexpensive and durable. In addition, the LED does not harm predators and parasitoids of the whitefly. Another technique used to reduce virus damage include the use of floating row covers, which are covers used to keep plants from exposure from pests. Field studies conducted in Australia have shown that the use of floating row covers coupled with insect growth regulators increase the yield of harvested fruit and quality and reduce virus damage to cucurbits.

Trap crops

Another important control is the use of other crops as a source of trap crops. Squashes can act as trap crops for the silverleaf whitefly due to the flies’ attraction to these crops. Silverleaf whiteflies are actually more attracted to the squash crop than they are to the tomato plant. When squash serves as a trap crop, the tomato yellow curl leaf virus can be controlled and limited. Scientific experiments show in the fields that growing squash crops around the areas where tomato plants can be found is a useful manipulation in regulating the silverleaf whitefly population as well as the transmission of TYLCV. Other plants that can serve as trap crops include cantaloupe and cucumber.

Cultural controls

Through a cultural control method, different planting areas can limit the amount of ''B. tabaci'' infected plants. Planting different host crops away from each other will decrease the number of plants the flies will be able to infect. Thus, the best control is to maximize the distance and time interval between host crops.UC IPM Pest Management Guidelines: Peppers
ipm.ucdavis.edu. December 2009. Good sanitation in winter and spring crops is also required for the maintenance and control of the fly population. Weeds and host crop residues must be removed immediately to avoid infestation. Silver/aluminum cover mulches can repel the adult silverleaf whitefly. Thus, when planting seeds, placing a reflective polyethylene mulch on planting beds will significantly reduce the rate of colonization. Cultural controls are very important to crops such as vegetables and fruit. For example, in the family Cucurbitaceae, vegetables such as watermelon and squash contract squash vein yellowing virus (SqVYV) by the silverleaf whitefly.Flores, A. (2007)
On the Guard Against Watermelon Vine Decline
pp. 10–11 ''Agricultural Research''. The SqVYV virus discovered by plant pathologist Benny Bruton and Shaker Kousik is essentially a crippling disease of the watermelon, which leads to the vine of the watermelon to collapse, causing the death of the watermelon before harvest. Kousik and pathologist

Scott Adkins Scott Edward Adkins (born 17 June 1976) is a British actor, film producer, screenwriter, gymnast, and martial artist. He is best known for his role as the Russian prison fighter Yuri Boyka in the ''Undisputed franchise''. He has played Yuri Boy ...

at ARS Subtropical Plant Pathology Research Unit worked together in screening the watermelon germplasm for resistance to SqVYV as to search for potential sources of resistance in wild-type watermelon. Kousik examined different combinations of insecticides and silver plastic mulch that could be used to reduce the whitefly populations.

References

External links

silverleaf whitefly
on the

University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...

Institute of Food and Agricultural Sciences The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is a teaching, research and Extension scientific organization focused on agriculture and natural resources. It is a partnership of federal, state, and county governmen ...

''Featured Creatures''
USDA Whitefly Knowledgebase

Center for Invasive Species Research summary on Silverleaf Whitefly
Species Profile – Silverleaf Whitefly (''Bemisia argentifolii'')
National Invasive Species Information Center,

United States National Agricultural Library The United States National Agricultural Library (NAL) is one of the world's largest agricultural research libraries, and serves as a national library of the United States and as the library of the United States Department of Agriculture. Located ...

. Lists general information and resources for Silverleaf Whitefly. {{DEFAULTSORT:Silverleaf Whitefly Whiteflies Hemiptera of North America Agricultural pest insects Insect vectors of plant pathogens Insects described in 1889