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AGRICULTURAL APPLICATION > Olive fruit fly
common name: Olive fruit fly
scientific name: Bactrocera oleae (Gmelin) (Insecta: Diptera: Tephritidae)
Below:
• Introduction
• Distribution
• Identification
• Life history and habits
• Hosts
INTRODUCTION
The olive fruit fly (Bactrocera oleae
(Gmelin), 1788) (formerly Dacus oleae) is a serious pest of olives in most of
the countries around the Mediterranean Sea. The larvae are monophagous,
and feed exclusively on olive fruits. Adults (photo 55,5 Kb) feed on nectar, honeydew, and
other opportunistic sources of liquid or semi-liquid food. The damage caused
by tunnelling of larvae in the fruit results in about 30 percent loss of the
olive crop in Mediterranean countries, and especially in Greece and Italy
where large commercial production occurs.
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DISTRIBUTION
Mediterranean basin,
northern, eastern and southern Africa, Canary Islands, India, western Asia, and apparently wherever olives
(the genus Olea) occur in the Eastern Hemisphere.
.
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IDENTIFICATION
Immature stages are
similar in appearance to those of other tephritid
fruit flies, especially Bactrocera spp. The olive fruit fly is one of the smaller species in
the genus. The adult (photo 55,5
Kb) female is
approximately 5 millimetres long, and has a wing expanse of approximately 10 millimetres. The
wings are mostly transparent and marked with brown, including a spot at the
wing tips. The thorax is black, with a silvery pubescence dorsal surface
stripped with three narrow parallel black lines. The humeri,
or shoulders, and an area above and below the base of the wings are yellow.
The inner portion of the scutellum is black, and
the posterior portion is yellow. The abdomen is black, covered with a
scattered grey pubescence. The basal segments are marked with pale transverse
bands and an irregular parallel bar or blotch of reddish-brown occupying the center of the apical segments. The terminal segment is
reddish-yellow. The sheath of the ovipositor is black, with the ovipositor
reddish in colour.
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LIFE HISTORY AND HABITS
In the Mediterranean
region, two to five generations of flies occur yearly. The winter is spent in
the pupal stage several centimetres below the soil and leaf
litter, and adult (photo 55,5
Kb) flies
emerge from March to May, depending upon the latitude and temperature. Under
summer conditions, a preoviposition period of six
to ten days elapses before mating, with longer time required earlier when
temperatures are not as high. During the preoviposition
period the female is maturing the ovary and a first set of eggs (photo 53,9 Kb). Beginning in June females
actively seek and oviposit in early maturing olive
fruits. From 10 to 12 eggs (photo 53,9 Kb) may be laid daily; usually one per olive fruit, and about 200 to 250
are laid in a lifetime. The female punctures the fruit with the ovipositor
and deposits an egg (photo 53,9
Kb) beneath
the skin. The legless larva (maggot) feeds upon the fruit tissue, causing the
fruit to drop off the tree. The egg (photo 53,9 Kb), larval and pupal
(photo 63,9 Kb) stages last 2 to 4, 10 to 14, and
about 10 days. Duration of the life cycle varies from one to six or seven
months. Male flies produce an auditory stridulatory
sound or signal during courtship. Courtship and mating occur at dusk, near
the end of the daylight period. Feral females likely mate several times
during their lifetime.
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HOSTS
Olives (Oleaspp).
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