Fruit Flies in Fiji
Fruit flies are a major concern for biosecurity as they cause damage to fruits and vegetables thus hindering production and decreasing exports. Fiji has seven species of fruit flies which include Bactrocera passiflorae, light form of B. passiflorae, B. xanthodes, B. distincta. B. gnetum, B. kirki and B. obscura. Two of these species B. kirki and B. obscura are only present on the island of Rotuma.
The adult female lays its egg by making a puncture on the fruit using a needle like a structure at the end of the abdomen, called the ovipositor and at the same time introducing bacteria into the fruit. In about two days, the egg hatches and the larvae remain in the fruit during the larvae stage. The bacteria break down the fruit, providing food for the larvae or maggots that hatch from the eggs.
Fruit damage caused by the fruit fly larvae becomes obvious after 3 days. The fruit tissue breaks down and black spot merges on the fruit surface. In 5 to 7 days symptoms of fruit fly damage is obvious through the rotting of the fruit. The rotten fruits fall to the ground, the larvae exits the fruit and pupate in the soil, emerging as an adult flies. The entire life cycle of the fruit fly takes 18 to 20 days.
Fruit fly monitoring and surveillance
The Biosecurity Authority of Fiji (BAF)’s fruit fly monitoring and surveillance programme entails monitoring for the presence of fruit fly with lure traps placed at high- risk locations throughout the country. This programme helps to provide assurance that Fiji is free from economically important fruit flies and as an early warning of fruit fly incursions to assist in an eradication effort.
The use of modified Steiner fruit fly traps with three types of pheromones: Methyl eugenol, Cuelure &Trimedlure, serves as an early detection warning system. BAF and the Extension Division of Ministry of Primary Industries (MPI) set up traps at all ports of entry (airports and wharves) and other high risk areas where exotic (foreign) fruit fly species are most likely to be detected in the country. These traps are cleared regularly and the specimens are indentified and recorded.
The two economically important fruit flies B. kirki and B. obscura which are present only in Rotuma pose significant threat to Fiji’s fruits and vegetables and also to Fiji’s fresh produce export.
The migration of B. kirki to Fiji is likely to pose a significant threat to Fiji’s fruits and vegetables and also affect Fiji’s fresh produce exports. Fiji has a Bilateral Quarantine Agreement (BQA) with New Zealand and Australia for export of fresh produce to these countries. The BQA ensures that a structured system is put in place to minimise the risk of injurious pests and diseases particularly fruit flies entering into these countries.
The migration of B. kirki can jeopardize the BQA with the two countries thus also hindering exports.Hence BAF has placed an internal biosecurity ban on shipment of all fruits to and from Rotuma. BAF would like to advise people travelling to and from Rotuma that it is prohibited to bring any fruits from Rotuma into Fiji.
People found in breach of this biosecurity regulation are liable for prosecution and penalties.