Silver Y Moth

Autographa gamma

1. Identification

• Common name: Silver Y moth
• Scientific name: Autographa gamma L.
• Order: Lepidoptera
• Family: Noctuidae

2. Pest description

• Green caterpillars, with a pale dorsal line and a typical “looping” movement.
• Adults with brownish forewings and a silvery “Y”-shaped marking, characteristic of the species.
• Migratory species, very common in horticultural crops.
• Caterpillars feed on leaves, potentially causing significant defoliation.
• Predominantly nocturnal activity.

3. Main hosts

• Leafy vegetables (lettuce, cabbage, spinach).
• Legumes.
• Tomato and other sensitive crops.
• Ornamental plants.
• Various spontaneous herbaceous plants.

4. Symptoms and damage

• Irregular perforations in the leaves.
• Partial or severe defoliation in intense attacks.
• Damage most evident in seedlings and young leaves.
• Reduced vigour and productivity of affected plants.

5. Biological cycle

• Eggs laid singly on the leaf surface.
• Caterpillars feed for several weeks, mainly at night.
• Pupation in the soil or in plant debris.
• Adults emerge throughout spring and summer.
• Several generations per year, reinforced by seasonal migrations.

6. Monitoring

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

7. Management measures

• Cultural: removal of infested plants; shallow soil tillage; control of spontaneous 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 thresholds are reached; integration of cultural and biological measures.

Bibliographic references

• EPPO Global Database – Autographa gamma.
• CABI – Invasive Species Compendium – Autographa gamma.
• Chinery, M. (1993). Collins Guide to the Insects of Britain and Western Europe. HarperCollins.
• Alford, D. V. (2007). Pest and Disease Management Handbook. Blackwell Publishing.
• Becher, P. G. & Revadi, S. (2020). Current knowledge on the migratory moth Autographa gamma as basis for future chemo‑ecological research. Progress in Biological Control.