Olive moth

Prays oleae

1. Identification

• Common name: Olive moth
• Scientific name: Prays oleae Bernard
• Order: Lepidoptera
• Family: Praydidae

2. Pest description

• Small caterpillars, cream-white to yellowish-green in colour, with a brown head.
• Small-sized adults (about 12–14 mm wingspan), with greyish forewings and a finely mottled pattern.
• Narrow, fringed hindwings.
• Species with three distinct annual generations: leaf-feeding (phyllophagous) generation (leaves), flower-feeding (anthophagous) generation (flowers) and fruit-feeding (carpophagous) generation (fruits).
• It attacks above all young leaves, inflorescences and developing fruits.

3. Main hosts

• Olive tree.
• Wild olive and other Oleaceae may be occasionally affected.

4. Symptoms and damage

• Phyllophagous generation: galleries in young leaves, perforations and partial curling.
• Anthophagous generation: destruction of flower buds and flowers, significantly reducing fruit set.
• Carpophagous generation: perforations in the fruit, internal galleries and premature drop of the olive.
• Severe damage can compromise the annual production, especially when it coincides with conditions favourable to the development of the pest.

5. Biological cycle

• Three generations per year, synchronised with the phenological cycle of the olive tree.
• Eggs laid on leaves, flower buds or fruits, depending on the generation.
• Caterpillars develop inside leaves, flowers or fruits.
• Pupation generally occurs on the vegetation or in shelters in the canopy.
• Adults emerge in a staggered manner, with population peaks characteristic of each generation.

6. Monitoring

• Observation of galleries in young leaves (phyllophagous generation).
• Counting of damaged flowers and presence of caterpillars in the inflorescences (anthophagous generation).
• Sampling of young fruits for detection of perforations and galleries (carpophagous generation).
• Pheromone traps for detection and monitoring of flights.
• Assessment of the percentage of affected organs at each phenological stage.

7. Management measures

• Cultural: removal of dry branches, improvement of canopy ventilation and adequate management of the productive load.
• Preventive: choice of less susceptible varieties and practices that favour vegetative balance.
• Biological: conservation of natural parasitoids, such as Chelonus elaeaphilus, and use of selective biological products.
• Integrated protection: monitoring with pheromones, definition of intervention thresholds specific to each generation and judicious application of authorised insecticides.

Bibliographic references

• CABI – Invasive Species Compendium – Prays oleae.
• EPPO Global Database – Prays oleae.
• Bento, A., Torres, L., & Lopes, J. (2001). A traça‑da‑oliveira Prays oleae: biologia e controlo. Revista de Ciências Agrárias, 24, 45–54.
• Tzanakakis, M. E. (2003). Seasonal development and dormancy of insects and mites feeding on olive. Entomologia Hellenica, 15, 47–77.