Tephritidae
(Also known as Trypetidae)
Taxonomic placing: Insecta, Holometabola, Diptera.
Common name: Fruit flies.
Geographical distribution: Fruit flies are world-wide in distribution, consisting of more than 4000 species in over 500 genera.
Morphology The adults are brightly colored, often with red and yellow markings or stripes, spotted wings and a strong, extendible ovipositor. Fully-grown maggots are whitish, up to 10 mm long, with posterior spiracles, each of which carries three simple slits.
Host plants: Economic plants that produce soft, succulent fruits, like apple, citrus, olives and many subtropical fruits as well as various vegetables. Other major hosts are in the family Asteraceae, within whose flowers the juveniles develop.
Life history The females insert their eggs, singly or in clusters, into the host-fruit (or, in rare cases, into leaves or stems). The flower-inhabiting species place their eggs between the bracts. A few hundred to 1,500 eggs may be produced by the females, which often mark the oviposition sites by a deterrent pheromone, in order to signal to other females. The emerging maggots develop within several weeks (but some temperate-zone species may be univoltine) and pupate in the soil. Generation time is usually about one month. The adults feed on various liquids, such as honeydew and sap flowing from the stung fruits, which is a protein-poor diet supplemented by internal microorganisms. The males often occur in leks that attract the females. Many species are attracted to ammonia and other volatiles, which serves for luring them to traps. A few species are leaf miners and others form galls.
Economic importance: Fruit flies are major pests of many fruits, including citrus, many cucurbits, mango, guava, olives, papaya. The larvae bore and feed in the fruit, causing their deterioration and drop, as well as providing entry ports for molds and for associated fungal diseases. Part of the importance of fruit flies is due to their being quarantine pests, which restricts fruit importation into some markets and/or require expensive disinfestations procedures. In addition, invading fruit fly pests may require expensive eradication. About 20 species have been assayed for the biological control of weeds, mostly in the Asteraceae.
Management
Monitoring: Fruit fly presence in orchards may be detected by finding the early, usually sterile stings in fruits, or more often, by trapping the early emergent males. There are variously-designed traps, baited with chemicals (with trade names such as Cue Lure, Trimedlure and Vert Lure) that attract different fruit fly species. In some cases ammonia alone will suffice. The traps are placed in the orchard and monitored periodically and replenished as necessary. Control decisions are based on the obtained data.
Cultural methods: Preventing the entry and establishment of Tephritidae in fruit fly-free land masses, such as New Zealand or (in regard to North America, is only by strict quarantine. If, however, a pest has managed to enter, eradication measures must be undertaken. In some cases, such as small gardens, each susceptible fruit may be wrapped in a paper bag.
Sterile Insect Technique (SIT): Mass-reared males are sterilize by irradiation and released in the field in vast numbers. Due to their large numbers they outcompete normal males in mating, and their progeny are sterile. This method is widely used in controlling the Mediterranean fruit fly, Ceratitis capitata.
Chemical control: Insecticides may be used as cover or bait sprays. The former are meant to reach fruit flies wherever they are, whereas the propose of the latter is to bring the pests to the pesticide. The bait sprays (an ammonia attractant and a pesticide) are usually applied only in spots, resulting in minimal damage to natural enemies. Organophosphates are often used (despite becoming less effective over the long years of use); pyrethroids, as well as neonicotinoids are very effective
Biological control: Many parasitoids, especially Braconidae, attack the fruit-infesting larvae, and may reduce pest populations by up to 90%. Birds and rodents that feed on the fruits also kill a large number of maggots. Many predators, including ants and beetles, feed on the pupae in the soil.
Fruit fly pests included in this compendium
Bactrocera oleae (Gmelin) (olive fly)
Bactrocera zonata (Saunders) (Peach fruit fly)
Ceratitis capitata (Wiedermann) (Mediterranean fruit fly)
Dacus ciliatus Loew Loew (Cucurbit fly)
Myiopardalis pardalina (Bigot) (Bigot) (Baluchistan melon fly)
References
Aluja, M. and Norrbom, A.A. (Eds) 1999. Fruit flies (Tephritidae): Phylogeny and Evolution of Behavior. CRC Press, Boca Raton.
Carrol, L.E., White, I.M., Friedberg, A., Norrbom, A.L., Dallwitz M.J. and Thompson F.C. 2002 Onward. Pest Fruit Flies of the World: Descriptions, Illustrations, Identification, and Information Retrieval. 8th Version, August, 2002.
Freidberg, A. (Ed) 2005-2006. Biotaxonomy of Tephritoidea. Israel Journal of Entomology 35-36: 1-599.
Freidberg, A. and Kugler, J. 1989. Diptera: Tephritidae. Fauna Palaestina, Insecta. Israel Academy of Sciences & Humanities, Jerusalem.
Robinson, A.S. and Hooper, G. (Eds) 1989. Fruit Flies, Their Biology, Natural Enemies and Control, Vol. I+II. Elsevier, Amsterdam.
White, I.M. and Elson-Harris, M.M. 1992. Fruit Flies of Economic Significance: Their Identification and Bionomics. ACIAR, Wallingford, UK.
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