Potato tuber moth

Phthorimaea operculella

1. Identification

• Common name: Potato tuber moth
• Scientific name: Phthorimaea operculella Zeller
• Order: Lepidoptera
• Family: Gelechiidae

2. Pest description

• Whitish to pinkish caterpillars, very mobile, that form galleries in the leaves, stems and tubers.
• Small adults, greyish, with narrow and fringed wings.
• It attacks above all the potato plant, both in the field and in storage.
• A species highly adapted to hot and dry climates.

3. Main hosts

• Potato plant.
• Tomato plant.
• Aubergine.
• Other cultivated and spontaneous solanaceous plants.

4. Symptoms and damage

• Serpentine galleries in the leaves.
• Perforations in the stems and internal tunnels.
• Perforated tubers, with residues and excrement.
• High loss of quality and post-harvest conservation.
• Strong economic impact in hot regions.

5. Biological cycle

• Several generations per year, accelerated by high temperatures.
• Eggs laid on the surface of leaves, stems or exposed tubers.
• Caterpillars penetrate the tissues quickly, where they complete their development.
• Pupation in the soil, on the plant or in storage.
• Adults active during much of the year in Mediterranean and tropical climates.

6. Monitoring

• Observation of galleries in the leaves and perforations in the tubers.
• Inspection of stored tubers.
• Pheromone traps for the detection of flights.
• Assessment of the percentage of affected plants and tubers.

7. Management measures

• Cultural: elimination of crop remains, covering of the tubers in the field, crop rotation and adequate ventilation in storage.
• Preventive: use of healthy tubers, physical protection of the storage piles and reduction of exposure to light.
• Biological: use of Bacillus thuringiensis in young stages and conservation of natural parasitoids.
• Integrated protection: regular monitoring, intervention thresholds and judicious application of authorised insecticides.

Bibliographic references

• EPPO Global Database – Phthorimaea operculella.
• CABI Invasive Species Compendium – Phthorimaea operculella.
• Rondon, S. I. (2010). The potato tuberworm: a literature review. American Journal of Potato Research, 87, 149–166.
• Sporleder, M., et al. (2004). Temperature-dependent development of Phthorimaea operculella. Environmental Entomology, 33, 490–496.
• Kroschel, J., et al. (2013). Integrated pest management of the potato tuber moth. Journal of Integrated Pest Management, 4, 1–10.
• Radcliffe, E. B., et al. (2009). Integrated Pest Management for Potatoes in the Global South. Springer.