PMC INSECT TRAP

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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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