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Crop Protection CompendiumDatasheet report for Aleurodicus destructor (coconut whitefly)
A. destructor is regarded as a typical representative of the genus Aleurodicus, which is the type genus of the subfamilyAleurodicinae. The subfamily is defined by characters occurring in the adults (relatively rich forewing venation, basedon a bifurcated vein R, plus the veins M and Cu; legs with paronychium in shape of a large spine; ventral abdominalwax-producing areas usually arranged in three and four pairs, respectively in males and females) and the pupal cases(large wax-producing compound pores occurring on the subdorsum; lingula large, tongue-shaped, extending beyondthe posterior margin of a vasiform orifice).
It is considered that the few species of the genus Aleurodicus (including A. destructor) described from southern Asiaand the western Pacific are probably not congeneric with the Neotropical representatives of the same genus (Martin,1996).
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Description
Egg
Eggs are about 0.31 mm long, elongate in shape, and yellow to brownish, dusted with powdered wax. The stalk isshort, bearing the egg in a prostrate position on the leaf.
Fourth-instar nymph (pupal case)
The pupal case is yellowish to brownish, subelliptical to ovate in shape, sometimes with a narrowed cephalad, 1.3-1.5mm long and 0.8-1.0 mm wide, covered by a copious secretion of white wax. On infested leaves, specimens of A.destructor may be completely hidden by wax. The wax rods, emerging from compound pores, are unusually long,attaining in more perfect specimens a length of 12-15 mm; they are generally broken and intermingled with bands orplates of wax from the marginal tubes. The subdorsum has wax-producing compound pores; one cephalic (smaller thanthe other ones) and six abdominal pairs, the latter ones are similar in size (up to 90 µm in diameter). Only scattered tinypores, without a submarginal zone of wide-rimmed pores punctuate the remainder of the dorsal surface. A vasiformorifice is subcordate, about as wide as it is long. The operculum is subrectangular, about twice as wide as it is long. Thelingula is large, tongue-shaped, and extends beyond the posterior margin of the vasiform orifice and bears four setae,of which two are much reduced. This is the stage used for identification purposes.
Adults
The vertex is rounded. The antennae have seven segments, of which the third is the longest. Forewings have veins R1,Rs and M present, sometimes with an indication of the Cu. Legs have the paronychium represented by a large spine.Male claspers are long and narrow; the penis is recurved and short.
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Distribution
The subfamily Aleurodicinae is mostly Neotropical in distribution. However, A. destructor remains largely restricted to itsnative Austro-Oriental-Pacific zoogeographical region.
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Distribution Table
The distribution in this summary table is based on all the information available. When several references are cited, theymay give conflicting information on the status. Further details may be available for individual references in theDistribution Table Details section which can be selected by going to Generate Report.
Continent/Country/Region Distribution LastReported
Origin FirstReported
Invasive Reference Notes
AsiaBrunei Darussalam(/cpc/datasheet/108378)
Present Mound and Halsey,1978; Martin, 1985;EPPO, 2014
Present Mound and Halsey,1978; Martin, 1985;EPPO, 2014
-Queensland(/cpc/datasheet/108621)
Present Mound and Halsey,1978; EPPO, 2014
-Victoria(/cpc/datasheet/108624)
Present Mound and Halsey,1978
-Western Australia(/cpc/datasheet/108625)
Present NHM, 1907
New Caledonia(/cpc/datasheet/108517)
Present EPPO, 2014
Papua New Guinea(/cpc/datasheet/108534)
Present Mound and Halsey,1978; Martin, 1985;EPPO, 2014
Solomon Islands(/cpc/datasheet/108553)
Present Mound and Halsey,1978; Martin, 1985;EPPO, 2014
Vanuatu(/cpc/datasheet/108605)
Present EPPO, 2014
Risk of Introduction
A. destructor is usually considered as a quarantine pest and its spread over the tropics should be limited. Quarantineauthorities in Europe (for example, UK) have occasionally intercepted it, but it has not become established.
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Hosts/Species Affected
The host range of A. destructor is less wide than that of A. cocois or A. dispersus. A. destructor is most likely to beencountered on palms.
A. destructor almost exclusively colonizes the leaves of host plants, on which the adults oviposit and the young larvaesettle after having inserted their mouth stylets. On infested leaves, the occurrence of A. destructor is evidenced by thedense tangle of white wax filaments that are abundantly secreted by the nymphs (through dorsal compound pores).Moreover, spots of sticky and transparent honeydew appear in the leaf areas where individuals of A. destructor occur,and they soon become covered in black sooty mould. In case of heavy infestations, honeydew may come to cover thewhole aerial part of the plant (leaves, stems and fruits) and this may lead to the plants acquiring an almost completelyblack appearance.
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List of Symptoms/Signs
Sign Life Stages TypeFruit / honeydew or sooty mouldInflorescence / honeydew or sooty mouldLeaves / honeydew or sooty mouldStems / honeydew or sooty mould
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Biology and Ecology
A. destructor is usually a polyvoltine species, having continuous cycles throughout the year, at least where conditionsare optimal and host plants are available.
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Notes on Natural Enemies
The natural enemies of A. destructor are poorly known. Neuroptera (Chrysopa sp.), Coccinellidae (Scymnus sp.) andSyrphidae (Bacca sp.) are predators of A. destructor (Costa Lima, 1968). The chalcid wasp, Coccophagus sp. is aparasitoid of A. destructor (Sorauer, 1956).
A. destructor is an occasional pest in tropical Australia.
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Diagnosis
A preparation of pupal cases in a slide mount (according to the procedures of Martin (1987)) may be used to confirmdiagnosis. Martin and Watson (1998) provide a key to species of Aleurodicus on coconut in the Caribbean.
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Detection and Inspection
The leaves, and especially their undersides, must be inspected for the characteristic waxy masses that indicate theoccurrence of a nymphal colony. Sooty mould and honeydew coat surfaces below the colony.
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Similarities to Other Species/Conditions
Several species of the genus Aleurodicus are crop pests. In addition to A. destructor, the Neotropical species A.pulvinatus, A. cocois and A. dispersus are similar. The latter is easily detectable, having only four pairs of abdominalcompound pores on the dorsum of pupal case. A. pulvinatus, A. cocois and A. destructor all live on coconut and otherpalms. They may be distinguished by peculiar characters of the dorsal abdominal compound wax pores; all are similarin size and very large in A. destructor, but the posterior two pairs are much smaller than the remaining ones in A.pulvinatus and A. cocois. The lingula has all four setae markedly conspicuous in A. pulvinatus and A. cocois, wherastwo setae are more reduced in A. destructor (Martin, 1987).
Biological control has a key role in achieving lasting control of A. destructor. Chemical applications, which usuallyensure only a temporary suppression, followed by a resurgence of the pest, should be considered only in case of heavyinfestations or when eradication of the insect from a newly colonized area is attempted. The use of oil emulsionscontaining organophosphorus insecticides may be considered. Particular attention should be paid to carefully treatingthe upper and lower surfaces of leaves.
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References
APPPC, 1987. Insect pests of economic significance affecting major crops of the countries in Asia and the Pacificregion. Technical Document No. 135. Bangkok, Thailand: Regional Office for Asia and the Pacific region (RAPA).
AVA, 2001. Diagnostic records of the Plant Health Diagnostic Services, Plant Health Centre, Agri-food & VeterinaryAuthority, Singapore.
Costa Lima A. Da, 1968. Quarto catalogo dos insetos que vivem nas plants do Brasil seus parasitos e predadores. Riode Janeiro, 2 (1): 622 pp.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization.http://www.eppo.int/DATABASES/pqr/pqr.htm (http://www.eppo.int/DATABASES/pqr/pqr.htm)
Martin JH, 1985. The whitefly of New Guinea (Homoptera: Aleyrodidae). Bulletin of the British Museum (NaturalHistory), Entomology, 50(3):303-351. (/cpc/abstract/19850527697)
Martin JH, 1987. An identification guide to common whitefly pest species of the world (Homoptera, Aleyrodidae).Tropical Pest Management, 33(4):298-322. (/cpc/abstract/19881110277)
Martin JH, 1988. Whitefly of northern Sulawesi, including new species from clove and avocado (Homoptera,Aleyrodidae). Indo-Malayan Zoology, 5:57-85.
Martin JH, 1996. Neotropical whiteflies of the subfamily Aleurodicinae established in the western Palaearctic(Homoptera: Aleyrodidae). Journal of Natural History, 30(12):1849-1859; 16 ref. (/cpc/abstract/19971100768)
Martin JH; Watson GW, 1998. Aleurodicus pulvinatus (Maskell) (Homoptera: Aleyrodidae), and its emergence as a pestof coconut in the Caribbean. Journal of Natural History, 32(1):85-98; 20 ref. (/cpc/abstract/19981109381)
Mound LA; Halsey SH, 1978. Whitefly of the world. A systematic catalogue of the Aleyrodidae (Homoptera) with hostplant and natural enemy data. Chichester, UK: John Wiley and Sons. (/cpc/abstract/19780557087)
Sorauer P, 1956. Handbuch der Pflanzenkrankheiten. Berlin, Germany, 399 pp.
Waterhouse DF, 1993. The Major Arthropod Pests and Weeds of Agriculture in Southeast Asia. ACIAR Monograph No.21. Canberra, Australia: Australian Centre for International Agricultural Research, 141 pp. (/cpc/abstract/19931169986)