Bactrocera psidii (South Sea guava fruit fly)
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Risk of Introduction
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Bactrocera psidii (Frogg.)
Preferred Common Name
- South Sea guava fruit fly
Other Scientific Names
- Dacus ornatissimus Frogg.
- Dacus psidii (Frogg.)
- Dacus virgatus Coquillett
- Strumeta psidii (Frogg.)
- Tephritis psidii Frogg.
- DACUPS (Bactrocera psidii)
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Diptera
- Family: Tephritidae
- Genus: Bactrocera
- Species: Bactrocera psidii
Notes on Taxonomy and NomenclatureTop of page B. psidii is a member of subgenus Bactrocera within the genus Bactrocera. Its name may therefore be cited as Bactrocera (Bactrocera) psidii.
DescriptionTop of page Egg
The eggs of B. oleae are described in detail by Margaritis (1985), and those of other species are probably very similar. Size, 0.8 mm long, 0.2 mm wide, with the micropyle protruding slightly at the anterior end. The chorion is reticulate (requires scanning electron microscope examination). White to yellow-white in colour.
The puparium is barrel-shaped with most larval features being unrecognisable, with the exception of the anterior and posterior spiracles that are little changed by pupariation. White to yellow-brown in colour. Size is approximately 60-80% the length of the larva.
The genus Bactrocera belongs to the family Tephritidae, which is part of the superfamily Tephritoidea. As with most species of Tephritoidea, B. psidii has patterned wings, and the female has a long telescopic and pointed ovipositor; these features are hardly known outside the Tephritoidea. The family Tephritidae may also be separated from all other Diptera by the shape of the subcostal vein, which bends abruptly through a right-angle and fades to a fold before reaching the wing edge, combined with the presence of setulae along the dorsal side of vein R1. At the wing base, species of Bactrocera and Dacus have a very deep cell bm and a very long pointed extension of cell bcu (= cup). The genus Bactrocera, is separated from Dacus, by the terga (dorsal sclerites of the abdomen) not being fused into a single sclerotized plate.
As with most species in or close to subgenus Bactrocera, the scutum has two pale lateral vittae (lateral stripes). The scutum has both anterior supra-alar setae and prescutellar acrostichal setae; there are two setae (apical pair) on the margin of the scutellum. The males have a deep V-shaped notch in the 5th sternite and a pecten (comb of setae) on each side of the third abdominal tergite.
This species is unusual in that its wing patterning is very pale (and includes a mark along the R-M crossvein) and its scutellum is marked with a large black triangle; its abdomen is also entirely dark (black or dark orange-brown). For a species level identification see White and Hancock (1997) or Drew (1989).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Risk of IntroductionTop of page B. psidii poses a threat to areas of suitable climate with potential host crops.
Hosts/Species AffectedTop of page The data presented in the host tables are from a recent survey by Amice and Sales (1997).
Host Plants and Other Plants AffectedTop of page
|Aleurites moluccanus (candlenut tree)||Euphorbiaceae||Other|
|Anacardium occidentale (cashew nut)||Anacardiaceae||Other|
|Annona reticulata (bullock's heart)||Annonaceae||Other|
|Citrus maxima (pummelo)||Rutaceae||Other|
|Diospyros sp.||Ebenaceae||Wild host|
|Eugenia uniflora (Surinam cherry)||Myrtaceae||Other|
|Ficus sp. (fig)||Moraceae||Wild host|
|Mangifera indica (mango)||Anacardiaceae||Other|
|Prunus persica (peach)||Rosaceae||Main|
|Psidium cattleianum (strawberry guava)||Myrtaceae||Other|
|Psidium guajava (guava)||Myrtaceae||Main|
|Syzygium jambos (rose apple)||Myrtaceae||Other|
|Syzygium malaccense (Malay apple)||Myrtaceae||Other|
|Terminalia catappa (Singapore almond)||Combretaceae||Other|
Growth StagesTop of page Fruiting stage
SymptomsTop of page Fruit which have been attacked by B. psidii show signs of oviposition punctures around which necrosis may occur.
List of Symptoms/SignsTop of page
|Fruit / discoloration|
|Fruit / gummosis|
|Fruit / internal feeding|
|Fruit / lesions: black or brown|
|Fruit / lesions: scab or pitting|
|Fruit / obvious exit hole|
|Fruit / odour|
|Fruit / ooze|
Biology and EcologyTop of page The eggs of Bactrocera species are laid below the skin of the host fruit. These usually hatch within a day and the larvae feed for 10-35 days, depending on the season. There are three larval instars. Pupariation occurs in the soil under the host plant for 10-30 days. Adults occur throughout the year and begin mating after approximately 1-2 weeks, and may live up to 1-3 months depending on the temperature (Christenson and Foote, 1960).
Natural enemiesTop of page
Notes on Natural EnemiesTop of page Predation of larvae as a result of vertebrates eating infested fruit and predation of puparia in the soil (for example, by ants), are generally regarded as major causes of fruit fly mortality (White and Elson-Harris, 1994). Recent surveys in the South Pacific have indicated that levels of larval parasitism are low, generally less than 10% (Allwood, 1997).
Means of Movement and DispersalTop of page Adult flight and the transport of infested fruit are the major means of movement and dispersal to new areas.
Pathway VectorsTop of page
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Fruits (inc. pods)||eggs; larvae||Yes||Pest or symptoms usually visible to the naked eye|
|Growing medium accompanying plants||pupae||Yes||Pest or symptoms usually visible to the naked eye|
|Plant parts not known to carry the pest in trade/transport|
|Stems (above ground)/Shoots/Trunks/Branches|
|True seeds (inc. grain)|
ImpactTop of page B. psidii is a major pest (Drew and Romig, 1997). In New Caledonia, untreated Psidium guajava (guava) and Prunus persica (peach) were attacked by an average of 10 and 3 flies per fruit respectively, when exposed to both B. psidii and B. tryoni. However, in guava B. tryoni is approximately ten times more important than B. psidii, while in peach B. psidii is approximately twice as abundant as B. tryoni (Amice and Sales, 1997).
Detection and InspectionTop of page
The males of this species are attracted to a cue lure which is mixed with an insecticide and is used as a bait in a trap based on the Steiner trap (White and Elson-Harris, 1994). However, both sexes may be monitored using protein bait traps (either protein hydrolysate or protein autolysate) (Drew, 1982b). Field monitoring is largely carried out using traps within the areas of infestation. However, there is evidence that some fruit flies have different host preferences in different parts of their range, and host fruit surveys should also be considered as part of the monitoring process.
Many countries that are free of Bactrocera species, such as the USA (California and Florida) and New Zealand, maintain a grid of methyl eugenol (a male attractant for many other species) and cue lure traps in high-risk areas (for example, ports and airports). These traps may also be placed within other regions with a potential climate for infestation.
Fruit which are grown locally or samples of fruit imports, should be inspected for puncture marks and any associated necrosis. Suspect fruit should be cut open and checked for larvae. Larval identification is difficult, mature larvae should be transferred to sawdust (or a similar dry medium) to allow pupariation. Upon emergence, adult flies must be fed with sugar and water for several days to allow hardening and full colour to develop, before they can be identified.
Similarities to Other Species/ConditionsTop of page Details provided in the Morphology Section, and White and Hancock (1997), should be sufficient to allow diagnosis of this species.
Prevention and ControlTop of page
Control of South Pacific fruit flies is reviewed by Allwood (1997). When detected, it is important to gather all fallen and infected host fruits, and destroy them. Baited traps should be continuously used to monitor the population size and spread. One of the most effective control techniques against fruit flies is to wrap the fruit, either in newspaper, paper bags or polythene sleeves. This is a simple physical barrier to oviposition but it must be applied well before the fruit is attacked. Early harvesting is also an effective control, because very few Bactrocera species attack the fruit prior to ripening.
Although cover sprays of the entire crop are sometimes used, bait sprays are both more economical and more environmentally acceptable. A bait spray consists of a suitable insecticide (for example, malathion), which is mixed with a protein bait (Roessler, 1989); practical details are given by Bateman (1982). Both male and female fruit flies are attracted to protein sources which emanate ammonia, and so insecticides can be applied to just a few spots in an orchard and the flies will be attracted to these spots. The protein most widely used is hydrolysed protein, but some supplies of this are acid hydrolysed which are highly phytotoxic. Smith and Nannan (1988) have developed a system using autolysed protein. In Tonga this has been developed into a very effective commercial product derived from brewery waste (Heimoana et al., 1997).
Many countries, such as the USA, forbid the import of susceptible fruit without a strict post-harvest treatment having been applied by the exporter. This may involve fumigation, heat treatment (hot vapour or hot water), cold treatments or insecticidal dipping (Armstrong and Couey, 1989; Armstrong, 1997). Heat treatment tends to reduce the shelf life of most fruits, and so the most effective method of regulatory control is to restrict imports of a given fruit to areas free of fruit fly attack. The heat tolerance of the immature stages of B. psidii were studied by Sales et al. (1997).
ReferencesTop of page
Allwood AJ, 1997. Control strategies for fruit flies (family Tephritidae) in the South Pacific, In: Allwood AJ, Drew RAI, eds. Management of Fruit Flies in the Pacific. A Regional Symposium, Nadi, Fiji. ACIAR Proceedings, 76: 171-182.
Amice R, Sales F, 1997. Fruit fly fauna in New Caledonia. In: Allwood AJ, Drew RAI, eds. Management of Fruit Flies in the Pacific. A Regional Symposium, Nadi, Fiji. ACIAR Proceedings, 76: 68-76.
Armstrong JW, 1997. Quarantine treatment options for fruit fly host commodities for Pacific island countries. In: Allwood AJ, Drew RAI, eds. Management of Fruit Flies in the Pacific. A Regional Symposium, Nadi, Fiji. ACIAR Proceedings, 76: 222-224.
Armstrong JW, Couey HM, 1989. Control; fruit disinfestation; fumigation, heat and cold. In: Robinson AS, Hooper G, eds. Fruit Flies; their Biology, Natural Enemies and Control. World Crop Pests. Amsterdam, Netherlands: Elsevier, 3(B):411-424.
Bateman MA, 1982. III. Chemical methods for suppression or eradication of fruit fly populations, In: Drew RAI, Hooper GHS, Bateman MA eds. Economic Fruit Flies of the South Pacific Region. 2nd edn. Brisbane, Australia: Queensland Department of Primary Industries, 115-128.
Christenson LD, Foote RH, 1960. Biology of fruit flies. Annual Review of Entomology, 5:171-192.
Drew RAI, 1982. I. Taxonomy, In: Drew RAI, Hooper GHS, Bateman MA, eds. Economic Fruit Flies of the South Pacific Region. 2nd edn. Brisbane, Australia: Queensland Department of Primary Industries,1-97.
Drew RAI, 1982. IV. Fruit fly collecting. In: Drew RAI, Hooper GHS, Bateman MA, eds. Economic fruit flies of the South Pacific Region, ed. 2. Brisbane, Australia: Queensland Department of Primary Industries, 129-139.
Drew RAI, Romig MC, 1997. Overview - Tephritidae in the Pacific and South-East Asia. In: Allwood AJ, Drew RAI, eds. Management of Fruit Flies in the Pacific. A Regional Symposium, Nadi, Fiji. ACIAR Proceedings, 76:46-53.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Heimoana V, Nemeye P, Langi T, Allwood AJ, 1997. Assessment of protein bait sprays for the control of fruit flies in chilli and capsicum crops in Tonga, In: Allwood AJ, Drew RAI, eds. Management of Fruit Flies in the Pacific. A Regional Symposium, Nadi, Fiji. ACIAR Proceedings, 76: 179-182.
Roessler Y, 1989. Control; insecticides; insecticidal bait and cover sprays. In: Robinson AS, Hooper G, eds. Fruit Flies. Their Biology, Natural Enemies and Control. World Crop Pests 3(B). Amsterdam, Netherlands: Elsevier, 329-336.
Sales F, Pauland D, Maindonald J, 1997. Comparison of egg and larval stage mortality of three fruit fly species (Diptera: Tephritidae) after immersion in hot water, In: Allwood AJ, Drew RAI, eds. Management of Fruit Flies in the Pacific. A Regional Symposium, Nadi, Fiji. ACIAR Proceedings, 76: 247-250.
Distribution MapsTop of page
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