Preferred name: Bactrocera tryoni
Authority: (Froggatt)
Taxonomic position: Animalia: Arthropoda: Hexapoda: Insecta: Diptera: Tephritidae
Other scientific names: Chaetodacus tryoni (Froggatt), Dacus ferrugineus tryoni (Froggatt), Dacus tryoni (Froggatt), Strumeta tryoni (Froggatt), Tephritis tryoni Froggatt
Common names in English: Queensland fruit fly
view more common names online...
Notes on taxonomy and nomenclature EPPO Categorization: A1 list
EU Categorization: A1 Quarantine pest (Annex II A)
view more categorizations online...
EPPO Code: DACUTR

Bactrocera tryoni has a wide range of hosts. In Australia, it has been reported from 234 plant species, belonging to 49 different families, according to the catalogue compiled by Hancock et al. (2000). Leblanc et al. (2012) gives a list of host plant records for the adventive populations in Pacific Islands. In total, it is reported from more than 250 different hosts. Fitt (1986) states that adults of B. tryoni exhibit no particular preference in the species of fruits on which they will lay eggs, but Clarke et al. (2011) argue that data on relative susceptibility are largely missing. The main hosts of interest are fruit trees: Annona, Averrhoa carambola, avocados (Persea americana), Citrus, Fortunella, guavas (Psidium guajava), Malus, mangoes (Mangifera indica), passion fruits (Passiflora edulis), pawpaws (Carica papaya), peaches (Prunus persica), plums (Prunus domestica) and Pyrus. However, vegetables such as tomatoes (Lycopersicon esculentum) are also infested. Many tree fruit crops of the EPPO region are potential hosts.

Host list: Acca sellowiana, Acronychia acidula, Acronychia laevis, Acronychia vestita, Actinidia deliciosa, Aegle marmelos, Aglaia sapindina, Alyxia ruscifolia, Amorphospermum antilogum, Anacardium occidentale, Annona glabra, Annona muricata, Annona reticulata, Annona squamosa, Annona x atemoya, Artocarpus altilis, Artocarpus heterophyllus, Artocarpus odoratissimus, Averrhoa bilimbi, Averrhoa carambola, Barringtonia asiatica, Barringtonia calyptrata, Barringtonia edulis, Beilschmiedia obtusifolia, Blighia sapida, Bouea macrophylla, Calophyllum inophyllum, Cananga odorata, Canarium indicum, Capparis lucida, Capparis mitchellii, Capparis nobilis, Capsicum annuum, Capsicum frutescens, Carallia brachiata, Carica papaya, Carissa ovata, Cascabela thevetia, Casimiroa edulis, Casimiroa tetrameria, Castanospermum australe, Castanospora alphandii, Chrysophyllum cainito, Cissus antarctica, Cissus sp., Citrus glauca, Citrus maxima, Citrus medica, Citrus reticulata, Citrus x aurantiifolia, Citrus x aurantium var. paradisi, Citrus x aurantium var. sinensis, Citrus x aurantium, Citrus x latifolia, Citrus x limon var. limetta, Citrus x limon, Citrus x limonia var. jambhiri, Clausena lansium, Coffea arabica, Coffea sp., Cryptocarya erythroxylon, Cucurbita moschata, Cucurbita pepo, Cydonia oblonga, Davidsonia pruriens, Dimocarpus longan, Diospyros australis, Diospyros discolor, Diospyros ebenum, Diospyros kaki, Diospyros mespiliformis, Diospyros nigra, Diplocyclos palmatus, Dovyalis caffra, Drypetes deplanchei, Elaeocarpus angustifolius, Elaeocarpus bancroftii, Elaeodendron australe, Endiandra compressa, Endiandra cowleyana, Endiandra discolor, Endiandra longipedicellata, Endiandra microneura, Endiandra sankeyana, Endiandra wolfei, Eriobotrya japonica, Eugenia dombeyi, Eugenia reinwardtiana, Eugenia uniflora, Fagraea gracilipes, Ficus carica, Ficus leptoclada, Ficus macrophylla, Ficus pancheriana, Ficus racemosa, Ficus sp., Flacourtia inermis, Flacourtia jangomas, Flacourtia rukam, Fortunella crassifolia, Fortunella japonica, Fragaria sp., Fragaria vesca, Ganophyllum falcatum, Garcinia dulcis, Garcinia warrenii, Glochidion harveyanum, Glycosmis trifoliata, Grewia asiatica, Hernandia cordigera, Huberantha nitidissima, Inocarpus fagifer, Juglans regia, Litchi chinensis, Maclura cochinchinensis, Malpighia emarginata, Malpighia glabra, Malus sylvestris, Mangifera indica, Manilkara zapota, Melastoma malabathricum, Melodorum leichhardtii, Mimusops elengi, Momordica charantia, Morinda citrifolia, Morus alba, Morus nigra, Murraya paniculata, Musa troglodytarum, Musa x paradisiaca, Myrciaria cauliflora, Nauclea orientalis, Nephelium lappaceum, Nerium oleander, Niemeyera chartacea, Niemeyera prunifera, Normanbya normanbyi, Notelaea longifolia, Ochrosia elliptica, Ochrosia moorei, Olea europaea, Opuntia ficus-indica, Opuntia sp., Owenia venosa, Passiflora aurantia, Passiflora edulis f. flavicarpa, Passiflora edulis, Passiflora foetida, Passiflora laurifolia, Passiflora quadrangularis, Passiflora suberosa, Passiflora subpeltata, Persea americana, Phaleria clerodendron, Phoenix dactylifera, Phyllanthus acidus, Phyllanthus ferdinandi, Physalis peruviana, Planchonella australis, Planchonella myrsinodendron, Planchonella pohlmaniana, Planchonella sp., Planchonella sphaerocarpa, Planchonia careya, Pleiogynium cerasiferum, Pleioluma macrocarpa, Polyalthia sp., Pometia pinnata, Pourouma cecropiifolia, Pouteria caimito, Pouteria campechiana, Pouteria sapota, Premna serratifolia, Prunus armeniaca, Prunus avium, Prunus cerasifera, Prunus domestica, Prunus persica var. nucipersica, Prunus persica, Prunus simonii, Psidium acutangulum, Psidium cattleyanum, Psidium guajava, Psidium guineense, Punica granatum, Pyrus communis, Pyrus pyrifolia, Rhamnella vitiensis, Rhodamnia sessiliflora, Ripogonum album, Rollinia mucosa, Rubus fruticosus, Rubus x loganobaccus, Salacia chinensis, Sandoricum koetjape, Santalum lanceolatum, Scaevola taccada, Schizomeria ovata, Semecarpus australiensis, Siphonodon australis, Solanum betaceum, Solanum laciniatum, Solanum lycopersicum, Solanum mauritianum, Solanum melongena, Solanum muricatum, Solanum seaforthianum, Solanum torvum, Spondias dulcis, Spondias mombin, Synsepalum dulcificum, Syzygium alliiligneum, Syzygium angophoroides, Syzygium aqueum, Syzygium australe, Syzygium canicortex, Syzygium claviflorum, Syzygium coarctatum, Syzygium cormiflorum, Syzygium corynanthum, Syzygium cumini, Syzygium erythrocalyx, Syzygium fibrosum, Syzygium forte, Syzygium graveolens, Syzygium hemilamprum, Syzygium jambos, Syzygium kuranda, Syzygium luehmannii, Syzygium malaccense, Syzygium paniculatum, Syzygium puberulum, Syzygium resa, Syzygium rubrimolle, Syzygium samarangense, Syzygium smithii, Syzygium suborbiculare, Syzygium tierneyanum, Syzygium xerampelinum, Terminalia arenicola, Terminalia aridicola, Terminalia catappa, Terminalia ferdinandiana, Terminalia melanocarpa, Terminalia muelleri, Terminalia platyphylla, Terminalia sericocarpa, Terminalia subacroptera, Trichosanthes cucumerina var. anguina, Vaccinium sp., Vitis labrusca, Vitis sp., Vitis vinifera, Ximenia americana, Ziziphus mauritiana

This species is found in Eastern Australia, from the Northern Territory, and Queensland southwards to New South Wales and the eastern part of Victoria. It is also reported from the Torres Strait Islands. See Dominiak & Mapson (2017) for a review of the distribution in Eastern Australia. It was introduced and became established in French Polynesia, New Caledonia, and Pitcairn Island (Leblanc et al., 2012). It has been introduced in other areas but eradicated.

Oceania: Australia (New South Wales, Northern Territory, Queensland, Victoria), French Polynesia, New Caledonia, Pitcairn

The general life cycle is similar to those of other Bactrocera species infesting fruits: eggs are deposited inside fruits by the female puncturing the fruit skin. Three larval stages develop inside the fruit, feeding on the plant tissue. Once mature the third instar larva will leave the fruit, dig down into the soil and turn into a pupa enclosed in a puparium. The adult fly will emerge from the puparium. During summer larvae mature in 7-10 days, while the pupal stage lasts about 10 days. The full life cycle can be completed in 2.5 weeks during summer but will take considerably longer in cooler conditions. A detailed overview of developmental rates and population dynamic models in relation to different weather conditions in Australia, is given in Yonow et al. (2004). Models predict 12-15 generations in the tropical parts of Australia, to 3-4 generations in Southern New South Wales (Clarke, 2019). Adults usually live around 80 days but can survive 7 to 8 months when overwintering (Clarke, 2019). The ability of B. tryoni to survive repeated frosts has been studied by Meats & Fitt (1987). In their review of overwintering of B. tryoni, Clarke et al. (2019) state that available data show the fly to overwinter almost exclusively as an adult.

Symptoms

Attacked fruit will usually show signs of oviposition punctures. Fruit with a high sugar content, such as peaches, will exude a sugary liquid, which usually solidifies adjacent to the oviposition site.

Morphology

Larva

Fruit fly larvae in general have a typical shape, i.e., cylindrical maggot-shape, elongate, anterior end narrowed and somewhat recurved ventrally, with anterior mouth hooks, and flattened caudal end. Their length varies from 5 to 15 mm. Identification to species level is not possible based on larvae. The 3rd-instar larvae have been described by White & Elson-Harris (1992) and Carroll et al. (2004). The former work provides a key to 3^rd-instar larvae which is useful for an identification to genus level. 

Adult (after diagnostic description of Drew, 1989)

Male

Medium sized (5-8 mm) species; medium sized black facial spots present; humeral calli and notopleural calli yellow; mesonotum red-brown with fuscous markings, mesopleural stripe reaching midway between anterior margin of notopleural callus and anterior npl. bristle, lateral postsutural vittae present, media postsutural vitta absent, scutellum yellow; wing with a narrow fuscous costal band and broad fuscous anal streak, costal cells fuscous, microtrichia covering second costal cell and outer half of first costal cell; abdominal terga III-V generally red-brown with a medial and 2 broad lateral longitudinal fuscous bands over all 3 terga and joined along anterior margin of tergum III; paler forms of the abdomen are often present. 

Female

As for male except no dense aggregation of microtrichia around A1+CuA2; supernumerary lobe weak; pecten of cilia on abdominal tergum III absent; ovipositor basal segment red-brown in, dorsoventrally compressed and tapering in dorsal view; ratio of length of oviscape to length of tergum V, 0.53:1; apex of piercer rounded.

Remark: B. tryoni belongs to a species complex (see Drew, 1989) and differentiation between this species and closely related species is difficult and needs expert confirmation. Separation between B. tryoni and B. neohumeralis cannot be done reliably on morphological grounds. See Clarke et al. (2011) and Clarke (2019) for a discussion on the differentiation of species within the tryoni complex. 

DNA barcoding

The molecular identification of B. tryoni through DNA barcoding proves to be problematic as this species cannot be properly distinguished from a number of closely related species, including B. aquilonis and B. neohumeralis. Additionally, the presence of unidentified / possibly misidentified reference sequence in Barcoding Index Number Systems (BINs) in which this species is represented, might also bias its molecular identification. Sequences are available in the Barcode of Life Data Systems (BOLD) and EPPO-Q-Bank.

Detection and inspection methods

Males are attracted to cue lure (Drew, 1989) and melolure (Royer, 2015). Schutze et al. (2016) discuss the efficiency of a visual trap (‘Ladd trap’) for monitoring both sexes of B. tryoni. Both sexes can be monitored by traps baited with protein-based attractants.  The trapping system used to monitor for possible introductions of B. tryoni into New Zealand has been described by Cowley (1990). Detection is also possible by examination of fruit for oviposition punctures and then rearing the larvae through to the adult stage.

Transport of infested fruits is the main mean of movement and dispersal to previously uninfested areas.  Adult flight can also result in dispersal but previous citations of long (50-100 km) dispersal movements for Bactrocera spp. are unsubstantiated according to a recent review by Hicks et al. (2019). Meats et al. (2003) established that the dispersal rate was almost always less than 1 km.

Economic impact

In Australia, B. tryoni is a serious pest of a wide variety of unrelated fruit and vegetable crops (Dominiak, 2012). Sutherst et al. (2000) estimated the annual cost in Australia to be between 25.7 and 49.9 million AUD. 

Control

Management for this species includes the general control measures for Bactrocera spp. (see Vargas et al. 2015 for an overview of management options). These include sanitation (to gather all fallen and infested host fruits and destroy them). Insecticidal protection is possible by using a cover spray or a bait spray. Bait sprays work on the principle that both male and female tephritids are strongly attracted to a protein source from which ammonia emanates. Bait sprays have the advantage over cover sprays in that they can be applied as a spot treatment so that the flies are attracted to the insecticide and there is minimal impact on natural enemies and other beneficials. A specific area-wide management approach for this species in Queensland, using bait spraying and Male Annihilation Technique (MAT), and its effects on trap catches and overall fruit fly infestation is given in Lloyd et al. (2010). Clarke et al. (2011) gives an overview of ecological factors relevant to control techniques, while Clarke (2019) discusses different aspects of management practices used against B. tryoni and other Bactrocera species.

Sterile Insect Technique (SIT) application specifically for this species has been deployed at quarantined areas for localized outbreaks (Jessup et al., 2007).

Phytosanitary risk

Bactrocera tryoni is a known pest of several fruit and vegetable crops in the area where it is present. It can be moved in trade with infested fruit. Although several studies were conducted on the present and potential distribution range of this species within Australia including the impact of climate change (e.g. Sutherst et al., 2000), no detailed study has been made on climatic suitability of the EPPO region, and it is unclear whether it could become established in the EPPO region. However, taken into consideration that the species co-occurred with Ceratitis capitata and displaced the latter in eastern Australia (Dominiak & Mapson, 2017), it is considered likely that B. tryoni could survive in parts of the EPPO region where C. capitata currently occurs. Transient populations could have impacts on the export of host fruit from the EPPO region. The EFSA Panel on Plant Health, in their Pest Categorization of non-EU Tephritidae (EFSA, 2020) placed B. tryoni on the list of fruit flies that satisfy the criteria to be regarded as a potential Union quarantine pest for the EU.

Consignments of fruits from countries or regions where B. tryoni occurs should be inspected for symptoms of infestation and those suspected should be cut open in order to look for larvae. Possible measures include that such fruits should come from an area where B. tryoni does not occur, or from a place of production found free from the pest by regular inspection for 3 months before harvest. Cold treatment and irradiation are described in the USDA treatment manual (USDA, 2021). Annex 16 to 18 of ISPM 28 Phytosanitary treatments for regulated pests (FAO, 2015) describe a cold treatment for B. tryoni on Citrus sinensis, Citrus reticulata x C. sinensis and Citrus limon, respectively. Annex 5 of ISPM 28 Phytosanitary treatments for regulated pests (FAO, 2009) describes an irradiation treatment for Bactrocera tryoni. 

Plants of host species transported with roots from countries where B. tryoni occurs should be free from soil, or the soil should be treated against puparia. The plants should not carry fruits.

Carroll LE, Norrbom AL, Dallwitz MJ & Thompson FC (2004). Pest fruit flies of the world – larvae. Version 9^th April 2019. https://www.delta-intkey.com/ffl/www/bac_tryo.htm [accessed 15/11/2020]

Clarke AR (2019) Biology and Management of Bactrocera and Related Fruit Flies. CAB International, Wallingford, xiv+254pp

Clarke AR, Powell KS, Weldon CW & Taylor PW (2011) The ecology of Bactrocera tryoni (Diptera: Tephritidae): what do we know to assist pest management? Annals of Applied Biology 158, 26-54.

Clarke AR, Merkel K, Hulthen AD & Schwarzmueller F (2019) Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) overwintering: an overview. Austral Entomology 58, 3-8.

Cowley JM (1990) A new system of fruit fly surveillance trapping in New Zealand. New Zealand Entomologist 13, 81-84.

Dominiak BC (2012) Review of dispersal, survival, and establishment of Bactrocera tryoni (Diptera: Tephritidae) for quarantine purposes. Annals of the Entomological Society of America 105, 434-446.

Dominiak BC & Mapson R (2017) Revised distribution of Bactrocera tryoni in eastern Australia and effect on possible incursions of Mediterranean fruit fly: development of Australia’s eastern trading block. Journal of Economic Entomology 110, 2459-2465.

Drew RAI (1989) The tropical fruit flies (Diptera: Tephritidae: Dacinae) of the Australasian and Oceanian regions. Memoirs of the Queensland Museum 26, 1-521.

EFSA PLH Panel (EFSA Panel on Plant Health), Bragard C, Dehnen-Schmutz K, Di Serio F, Gonthier P, Jacques MA, Jaques Miret JA, Justesen AF, Magnusson CS, Milonas P, Navas-Cortes JA, Parnell S, Potting R, Reignault PL, Thulke HH, Van der Werf W, Vicent Civera A, Yuen J, Zappalà L, Bali EM, Papadopoulos N, Papanastassiou S, Czwienczek E & MacLeod A (2020) Pest categorization of non-EU Tephritidae. EFSA Journal 18, 5931, 62pp. https://doi.org/10.2903/j.efsa.2020.5931

FAO (2009) Annex 5 Irradiation treatment for Bactrocera tryoni. Rome, IPPC, FAO. https://assets.ippc.int/static/media/files/publication/en/2016/06/PT_05_2009_En_2016-04-22_PostCPM11_InkAm.pdf

FAO (2015a) Annex 16 Cold treatment for Bactrocera tryoni on Citrus sinensis. Rome, IPPC, FAO. https://assets.ippc.int/static/media/files/publication/en/2016/06/PT_17_2015_En_2016-05-27_PostCPM11_InkAm.pdf

FAO (2015b) Annex 17 Cold treatment for Bactrocera tryoni on Citrus reticulata x C. sinensis. Rome, IPPC, FAO. https://assets.ippc.int/static/media/files/publication/en/2016/06/PT_17_2015_En_2016-05-27_PostCPM11_InkAm.pdf

FAO (2015c) Annex 18 Cold treatment for Bactrocera tryoni on Citrus limon. Rome, IPPC, FAO. https://assets.ippc.int/static/media/files/publication/en/2016/06/PT_17_2015_En_2016-05-27_PostCPM11_InkAm.pdf

Fitt GP (1986) The roles of adult and larval specialisations in limiting the occurrence of five species of Dacus in cultivated fruits. Oecologia 69, 101-109.

Hancock DL, Hamacek EL, Lloyd AC & Elson-Harris MM (2000) The Distribution and Host Plants of Fruit Flies (Diptera: Tephritidae) in Australia. DPI Publications, Brisbane (Australia), 75 pp

Hicks CB, Bloem K, Pallipparambil GR & Hartzog HM (2019) Reported long-distance flight of the invasive Oriental fruit fly and its trade implications. In Area-Wide Management of Fruit Flies (eds Pérez-Staples D, Diaz-Fleischer F, Montoya P & Vera MT), pp. 9-26. CRC Press, Boca Raton (US) 

Jessup AJ, Dominiak B, Woods B, de Lima CBF, Tomkins A & Smallridge CJ (2007) Area-wide management of fruit flies in Australia. In Area-wide Control of Insect Pests: from Research to Field Implementation (Eds Vreysen MJB, Robinson AS & Hendrich J), pp 685-697. Springer Verlag, Dordrecht (the Netherlands)

Leblanc L, Vueti ET, Drew RAI & Allwood AJ (2012) Host plant records for fruit flies (Diptera: Tephritidae: Dacini) in the Pacific Islands. Proceedings of the Hawaiian Entomological Society 44, 11-53.

Lloyd AC, Hamacek EL, Kopittke RA, Peek T, Wyatt PM, Neale CJ, Eelkema M & Gu NG (2010) Area-wide management of fruit flies (Diptera: Tephritidae) in the Central Burnett District of Queensland, Australia. Crop Protection 29, 462-469.

Meats A & Fitt GP (1987) Survival of repeated frosts by the Queensland fruit fly, Dacus tryoni: experiments in laboratory simulated climates with either step or ramp fluctuations of temperature. Entomologia Experimentalis et Applicata 45, 9-16.

Meats AW, Clift AD & Robson MK (2003) Incipient founder populations of Mediterranean and Queensland fruit flies in Australia: the relation of trap catch to infestation radius and models for quarantine radius. Australian Journal of Experimental Agriculture 43, 397-406.

Royer JE (2015) Responses of fruit flies (Tephritidae: Dacinae) to novel male attractants in north Queensland, Australia, and improved lures for some pest species. Austral Entomology 54, 411-426.

Schutze MK, Cribb BW, Cunningham JP, Newman J, Peek T & Clarke AR (2016) ‘Ladd traps’ as a visual trap for male and female Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae). Austral Entomology 55, 324-329.

Sutherst RW, Collyer BS & Yonow T (2000) The vulnerability of Australian horticulture to the Queensland fruit fly, Bactrocera (Dacus) tryoni, under climate change. Australian Journal of Agricultural Research 51, 467-480.

USDA (2021) United States Department of Agriculture Treatment Manual.  https://www.aphis.usda.gov/import_export/plants/manuals/ports/downloads/treatment.pdf [accessed on 2021-04-23]

Vargas RI, Pinero JC & Leblanc L (2015) An overview of pest species of Bactrocera fruit flies (Diptera: Tephritidae) and the integration of biopesticides with other biological approaches for their management with a focus on the Pacific region. Insects 6, 297-318.

White IM & Elson-Harris MM (1992) Fruit flies of economic significance: their identification and bionomics. CAB International, Wallingford (UK), xii+601pp

Yonow T, Zalucki MP, Sutherst RW, Dominiak BC, Maywald GF, Maelzer DA & Kriticos DJ (2004) Modelling the population dynamics of the Queensland fruit fly, Bactrocera (Dacus) tryoni: a cohort-based approach incorporating the effects of weather. Ecological Modelling 173, 9-30.

CABI resources used when preparing this datasheet

CABI Datasheet on Pest https://www.cabi.org/isc/datasheet/17693

This datasheet was extensively revised in 2021 by Dr M. De Meyer. His valuable contribution is gratefully acknowledged.

EPPO (2024) Bactrocera tryoni. EPPO datasheets on pests recommended for regulation. https://gd.eppo.int (accessed 2024-05-08)

This datasheet was first published in the EPPO Bulletin in 1983 and revised in the two editions of 'Quarantine Pests for Europe' in 1992 and 1997, as well as in 2021. It is now maintained in an electronic format in the EPPO Global Database. The sections on 'Identity', ‘Hosts’, and 'Geographical distribution' are automatically updated from the database. For other sections, the date of last revision is indicated on the right.

CABI/EPPO (1992/1997) Quarantine Pests for Europe (1^st and 2^nd edition). CABI, Wallingford (GB).

EPPO (1983) Data sheets on quarantine organisms No. 41, Trypetidae (non-European). EPPO Bulletin 13(1).  https://doi.org/10.1111/j.1365-2338.1983.tb01715.x