Frosted orange moth

Gortyna flavago

1. Identification

• Common name: Frosted orange moth
• Scientific name: Gortyna flavago Denis & Schiffermüller
• Order: Lepidoptera
• Family: Noctuidae

2. Pest description

• Caterpillars whitish to pinkish in colour, with a robust body and a brown head.
• Adults with forewings of a brownish-orange tone, often with light spots and darker margins; greyish hindwings.
• Species associated with herbaceous plants and vegetable crops, capable of boring into stems and roots.
• Caterpillars develop inside plant tissues, causing structural damage.
• Mainly nocturnal activity, typical of noctuids.

3. Main hosts

• Asteraceae diversas (cardos, serralhas, tasneiras).
• Sensitive vegetable crops, especially tender roots and stems.
• Herbaceous ornamental plants.
• Spontaneous species that act as a reservoir.

4. Symptoms and damage

• Holes in stems and roots.
• Localized wilting due to interruption of the sap flow.
• Internal damage that can lead to plant collapse.
• Presence of excrement and disaggregated tissues in the bored areas.
• Reduction in the vigour and productivity of the affected plants.

5. Biological cycle

• Eggs laid at the base of plants or in the adjacent soil.
• Caterpillars penetrate the stems or roots, where they remain during development.
• Pupation occurs in the soil, in shallow chambers.
• Adults emerge in late summer or autumn.
• Generally one generation per year.

6. Monitoring

• Observation of holes and wilting symptoms.
• Searching for caterpillars inside the affected stems.
• Light traps for the detection of adults.
• Regular monitoring in sensitive crops during summer.

7. Management measures

• Cultural: removal of infested plants; crop rotation; control of spontaneous host plants.
• Preventive: frequent inspection of stems and roots; maintenance of clean, well-drained soils.
• Biological: promotion of natural enemies present in the soil.
• Integrated Protection: judicious application of authorized insecticides when intervention thresholds are reached; integration of cultural and preventive measures.

Bibliographic references

• EPPO Global Database – Gortyna flavago.
• CABI – Invasive Species Compendium – Gortyna flavago.
• 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.