Large yellow underwing moth

Noctua pronuba

1. Identification

• Common name: Large yellow underwing moth
• Scientific name: Noctua pronuba L.
• Order: Lepidoptera
• Family: Noctuidae

2. Pest description

• Robust caterpillars, brown to greenish in colour, with faint longitudinal lines and a smooth body.
• Adults with brown forewings, with variable patterns; bright yellow hindwings with a black marginal band, a striking feature of the species.
• Polyphagous species, widely distributed and common in agricultural environments, gardens and natural areas.
• Caterpillars feed on tender leaves and stems, and can cause significant damage in horticultural crops.
• Predominantly nocturnal activity.

3. Main hosts

• Horticultural crops (lettuce, cabbage, spinach, carrot).
• Ornamental plants.
• Grasses and spontaneous plants.
• Various cultivated and wild herbaceous plants.

4. Symptoms and damage

• Irregular perforations in the leaves.
• Partial or severe defoliation in intense attacks.
• Damage in seedlings and young leaves.
• Presence of caterpillars at the base of the plants or in the soil during the day.
• Reduction in the vigour and productivity of the affected plants.

5. Biological cycle

• Eggs laid in groups on low vegetation.
• Caterpillars feed for several weeks, mainly at night.
• Pupation occurs in the soil, in shallow chambers.
• Adults emerge in summer and autumn.
• Generally one generation per year, with more possibly occurring in mild climates.

6. Monitoring

• Direct observation of caterpillars and foliar damage.
• Searching for caterpillars at the base of the plants or in the soil.
• Light traps for the detection of adults.
• Regular monitoring in sensitive crops during the summer and autumn.

7. Management measures

• Cultural: removal of infested plants; surface tillage of the soil; control of spontaneous host plants.
• Preventive: frequent inspection of young leaves; maintenance of good cultural hygiene practices.
• Biological: application of Bacillus thuringiensis on young caterpillars; promotion of natural enemies.
• Integrated protection: judicious application of authorised insecticides when intervention thresholds are reached; integration of cultural and biological measures.

Bibliographic references

• EPPO Global Database – Noctua pronuba.
• CABI – Invasive Species Compendium – Noctua pronuba.
• Chinery, M. (1993). Collins Guide to the Insects of Britain and Western Europe. HarperCollins.
• Heath, J. & Emmet, A. M. (1983). The Moths and Butterflies of Great Britain and Ireland. Curwen Press.