Olive fruit fly

Bactrocera oleae

1. Identification

• Common name: Olive fruit fly
• Scientific name: Bactrocera oleae Rossi
• Order: Diptera
• Family: Tephritidae

2. Pest description

• Adults 4–5 mm, yellowish-brown body, greyish thorax and a brown spot on the wing
• White, apodous larvae, develop inside the olive
• Pupae inside the fruit or in the soil
• Eggs laid under the epidermis, leaving a visible dark spot

3. Main hosts

• Olive tree
• Attacks both table and oil varieties
• Highly specialised species, with no relevant alternative hosts

4. Symptoms and damage

• Sting visible as a dark spot on the epidermis
• Internal galleries in the pulp
• Premature fruit drop
• Increased acidity and loss of olive oil quality
• Greater susceptibility to secondary infections
• High economic losses in years favourable to the insect

5. Biological cycle

• Two to five generations per year
• Adults active from spring to autumn
• Egg laying in fruits after the stone hardens
• Larvae develop in 10–15 days
• Pupation in the fruit or in the soil
• Overwintering mainly as a pupa

6. Monitoring

• Yellow chromotropic traps or McPhail / Tephri
• Weekly counting of captures
• Fruit sampling to detect stings and larvae
• Assessment of the infestation percentage
• Intensive monitoring between July and October

7. Management measures

• Cultural: collection and destruction of fallen fruits; early harvesting in years of heavy attack; irrigation management to reduce susceptibility.
• Biological: use of natural parasitoids (Psyttalia concolor); conservation of beneficials.
• Integrated protection: continuous monitoring; bait treatments (protein + insecticide) during critical periods; application of authorised insecticides when intervention thresholds are reached; use of mass-trapping traps; biotechnical control strategies (attract-and-kill).

Bibliographic references

• EPPO Global Database – Bactrocera oleae
• CABI Invasive Species Compendium – Bactrocera oleae
• Daane, K. M. et al. (2011). Integrated management of olive fruit fly
• Malheiro, R. et al. (2015). Impact of B. oleae on olive oil quality
• Neuenschwander, P. et al. (1983). Biology and ecology of the olive fruit fly