Note, 2002. Vital information on the approximately 80 species of Namibian fruit flies has now been released in the Journal of the National Museum of Namibia, CIMBEBASIA, Volume 17: "An annotated checklist
and provisional atlas of Namibian Tephritidae (Diptera: Schizophora)"
COMMON NAMESFruit fly, pumpkin fly (English); No local names are recordedFruit fly damage has been recorded all over northern Namibia. Various species are involved, but the primary pest species on different crops have not yet been studied. It will take some years before the main pest fruit fly species have been recorded and investigated. Dacus species (pumpkin fly)
Fruit fly, type 2
PEST STATUSFruit flies are major pests on cucurbits and a wide range of fruits. In most areas of north central Namibia, production of cucurbits (pumpkin, sweet melon, cucumber and squash) is difficult or even impossible due to fruit fly infestations.All cultivated cucurbits are affected. The hosts also include the local Marula fruit tree and the few plantations with citrus or other fruit trees. Tomato plots have occasionally been heavily infested with fruit flies, but this is not very common. The local melons that are found in most fields in the north of Namibia do not seem to be affected by fruit flies. Detailed investigations are needed to determine the host range for each species of fruit fly. GENERAL DESCRIPTIONThe flies lay their eggs under the skin ("sting") young fruits of cucurbits or fruit trees. In suitable host plants, the egg will develop into a yellow maggot a few millimetres in length. The maggot feeds on the pulp of the fruit. When the maggot is ready to pupate, it leaves the fruit and drops to the ground where it pupates. A week or two after pupation, the adult fly hatches and it will begin to lay eggs after another week.The presence of fruit flies is best noticed on the symptoms of damage. Heavy attacks on young fruits lead to early fruit dropping or many rotten fruits on the plant. Cucurbit fruits often show a characteristic curving with a dark spot where the fruit was punctured during egg laying. In many cases, droplets of sap can be seen oozing from the puncture. When damaged fruits are cut open, the maggots can be seen in the fruit pulp. CONTROLEarly removal and destruction of fruit with fruit fly damage is recommended.A wide range of pesticides are available for use in orchards and gardens, most of which are systemic pesticides to control fly larvae inside the produce. At Ogongo Agricultural College, a bait method was tested, applying droplets of water and Malathion and sugar or Dipterex and sugar on the leaves of all cucurbits. Dead flies were found on the ground later on, but the control was not sufficient to reduce the fruit fly attack. Eventually the training garden was infested to such an extent that all cucurbit production was abandoned. If chemical control is found necessary, please contact the pest control officers for precise advice on chemical control. OTHER NOTESThe flies are easier to spot in the morning or late afternoon, when they rest on vegetation or dropped fruits. The flies prefer to rest on tall plants such as maize, sorghum or pearl millet, near the cucurbits. For a full identification of fruit flies and their host, it is important to collect fruits with maggots or attack symptoms and hand in the samples to the nearest pest control officer. The officer will then rear the fruit flies in cages, and send them for identification.During late 1998 a fruit fly trapping and monitoring project was initiated to record fruit flies in Namibia. The project uses traps with chemical lures in order to determine which species occur in which part of the country, and which lures may be most effective to determine infestation levels. April 2003 - new photos:During April 2003 fruit flies were again attracted to the yellow flowers of a bush outside our office. Live flies move a bit too fast for a digital camera but eventually I got a few shots where we can actually see the fly.
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