Fruit and vegetable movement on domestic flights in Papua New Guinea and the risk of spreading pest fruit-flies (Diptera : Tephritidae)

Species of tropical fruit-flies (Diptera: Tephritidae: Dacinae) are the foremost horticultural pest in the Pacific region. In Papua New Guinea (PNG), limiting the movement of fresh fruits and vegetables ( = fresh commodities) between different regions within the country is one plant protection strategy that could lessen the threat posed by fruit-flies by restricting the spread of both exotic and indigenous pest species. In order to assess the risk posed by informal fruit and vegetable movement, we carried out a survey of Papua New Guinea domestic airline passengers. Of 1904 passengers surveyed, 38.9% were carrying fresh commodities. Over 70 different fresh commodities were being carried, the most common being bananas and peanuts, each being carried by > 9% of passengers. Thirty-four of these 70 commodities are known fruit-fly hosts from PNG or other countries. Sixty-three per cent of passengers on flights into the National Capital District (i.e. Port Moresby) were carrying fruit, as were 74% of passengers leaving the Highland Provinces. Neither the purpose of travel nor the occupation type of a passenger influenced the likelihood of commodity carriage. Nearly all commodities came from gardens or local markets and were being carried predominantly for personal consumption or gifts. With fruit-fly infestation rates of susceptible crops being around 20%, we conclude that the risk of transport of fruit-flies is very high.