Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Bactrocera psidii
(South Sea guava fruit fly)



Bactrocera psidii (South Sea guava fruit fly)


  • Last modified
  • 05 December 2017
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Bactrocera psidii
  • Preferred Common Name
  • South Sea guava fruit fly
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Arthropoda
  •       Subphylum: Uniramia
  •         Class: Insecta

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TitleMuseum set specimen of adult B. psidii
Copyright©CABI BioScience
Museum set specimen of adult B. psidii©CABI BioScience


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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.

EPPO code

  • DACUPS (Bactrocera psidii)

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Uniramia
  •                 Class: Insecta
  •                     Order: Diptera
  •                         Family: Tephritidae
  •                             Genus: Bactrocera
  •                                 Species: Bactrocera psidii

Notes on Taxonomy and Nomenclature

Top of page B. psidii is a member of subgenus Bactrocera within the genus Bactrocera. Its name may therefore be cited as Bactrocera (Bactrocera) psidii.


Top 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).


Top of page The distribution of B. psidii is mapped by Drew (1982a).

Distribution Table

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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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes


New CaledoniaPresentDrew, 1982a; Amice and Sales, 1997; EPPO, 2014

Risk of Introduction

Top of page B. psidii poses a threat to areas of suitable climate with potential host crops.

Hosts/Species Affected

Top of page The data presented in the host tables are from a recent survey by Amice and Sales (1997).

Host Plants and Other Plants Affected

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Growth Stages

Top of page Fruiting stage


Top of page Fruit which have been attacked by B. psidii show signs of oviposition punctures around which necrosis may occur.

List of Symptoms/Signs

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SignLife StagesType
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 Ecology

Top 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 enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Biosteres longicaudatus Parasite Larvae
Psyttalia fijiensis Parasite Larvae

Notes on Natural Enemies

Top 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 Dispersal

Top of page Adult flight and the transport of infested fruit are the major means of movement and dispersal to new areas.

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Clothing, footwear and possessionsFruit in case or handbag. Yes
Containers and packaging - woodOf fruit cargo. Yes
Land vehiclesAeroplanes and boats, with fruit cargo. Yes
MailFruit in post. Yes
Soil, sand and gravelRisk of puparia in soil. Yes

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility 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
Seedlings/Micropropagated plants
Stems (above ground)/Shoots/Trunks/Branches
True seeds (inc. grain)


Top 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 Inspection

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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/Conditions

Top of page Details provided in the Morphology Section, and White and Hancock (1997), should be sufficient to allow diagnosis of this species.

Prevention and Control

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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).


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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, 1989. The tropical fruit flies (Diptera: Tephritidae: Dacinp) of the Australasian and Oceanian regions. Memoirs of the Queensland Museum, 26:521 pp.

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.

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.

Margaritis LH, 1985. Comparative study of the eggshell of the fruit flies Dacus oleae and Ceratitis capitata (Diptera: Trypetidae). Canadian Journal of Zoology, 63(9):2194-2206

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.

Smith D, Nannan L, 1988. Yeast autolysate bait sprays for control of Queensland fruit fly on passionfruit in Queensland. Queensland Journal of Agricultural and Animal Sciences, 45(2):169-177.

Waterhouse DF, 1993. Biological control: Pacific prospects - supplement 2. Canberra, Australia: ACIAR, 138 pp.

White IM, Elson-Harris MM, 1994. Fruit flies of economic significance: their identification and bionomics. Wallingford, UK: CAB International. Reprint with addendum.

White IM, Hancock DL, 1997. CABIKEY to the Dacini (Diptera, Tephritidae) of the Asian, Pacific and Australasian Regions. Wallingford, UK: CAB International.

Distribution Maps

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