Quarantine pests and their hosts

Australia has many species of fruit fly. These create significant domestic and export market access issues for fruiting vegetables. Various leafy, root and tuber crops may also be restricted from certain markets due to the presence of insects, nematodes or diseases in their production region. 

In Australia, fruit flies are responsible for more restrictions on produce movement than any other pest. These restrictions are a significant issue for many producers. While Queensland fruit fly (Qfly) is perhaps the most widely distributed, there are a number of different species that raise quarantine concerns. Species and distributions include:  

  • Mediterranean fruit fly (Ceratitis capitata) (Medfly) is only present in coastal areas of Western Australia 
  • Queensland fruit fly (Bactrocera tryoni) (Qfly) is widespread along the east coast from Melbourne to Cairns. It is also increasingly endemic in inland, irrigated areas of NSW and Victoria. Major vegetable production areas in Bundaberg and Bowen are affected by this species. 
  • Cucumber fly (Bactrocera cucumis) is widespread along the east coast from Coffs Harbour to North Qld as well as parts of the Northern Territory. 
  • Bactrocera neohumeralis is closely related to Qfly and has a similar, although generally more northern, distribution. 
  • Bactrocera jarvisi is an increasingly significant pest. It is mainly found in northern Australia but potentially as far south as Sydney in coastal areas. ​

Female Qfly laying eggs into a capsicum fruit

Fruit flies can infest any fruiting vegetable, although in some cases these products are not their preferred hosts. However, capsicum, chillies and tomatoes are highly attractive and susceptible to Qfly and MedflyCucurbits such as squash, zucchini and pumpkin are preferred hosts of cucumber fly, and can also be infested by other species.

Mature Qfly maggots in a chilli 

Other pests of quarantine significance include:

  • Various whitefly species including spiralling whitefly (Aleurodicus dispersus) and silverleaf whitefly (Bemisia tabaci). 
  • Melon thrips (Thrips palmi), which is found around Darwin, coastal north Queensland (Bowen to Cooktown) and north coastal NSW/ south Queensland (Lismore to Seventeen Seventy). 
  • Potato cyst nematode (PCN) in Victoria (Globodera rostochiensis). 
  • Currant lettuce aphid (Nasonovia ribis-nigri). 
  • Western flower thrips (Frankliniella occidentalis). 
  • Burrowing nematode (Radopholus similis). 


Silverleaf whitefly (left, Photo: USDA), currant lettuce aphid (centre, Photo: W Cranshaw, Bugwood.org) and Western flower thrips (right, Photo: DAFWA)