Sweet potato hawk moth

Agrius convolvuli

1. Identification

• Common name: Convolvulus hawk‑moth; Sweet potato hornworm
• Scientific name: Agrius convolvuli L.
• Order: Lepidoptera
• Family: Sphingidae

2. Pest description

• Robust caterpillars, of variable colour (green, brown or almost black), with lateral eyespots and the caudal horn typical of hawk‑moths; reaching 80–100 mm.
• Large adults, with greyish forewings and a fusiform body; wingspan of 80–120 mm.
• Migratory species, capable of covering long distances.
• Caterpillars feed on leaves and stems, and may cause significant defoliation.

3. Main hosts

• Sweet potato.
• Other Ipomoea spp..
• Spontaneous plants of the Convolvulaceae family.

4. Symptoms and damage

• Leaves partially eaten or completely consumed.
• Holes and irregular cuts in young leaves.
• Damage to tender stems, which may cause localised wilting.
• In intense attacks, reduction in the vigour and productivity of the crop.

5. Biological cycle

• Eggs laid singly on the underside of the leaves.
• Caterpillars develop over 3–4 weeks, passing through several instars.
• Pupation in the soil, in underground chambers.
• Adults emerge in summer and autumn; number of generations variable, depending on climatic conditions and migration.

6. Monitoring

• Direct observation of caterpillars and foliar damage.
• Searching for eggs and young caterpillars on the underside of the leaves.
• Regular assessment of sweet potato plots, especially in summer.
• Monitoring of adults through nocturnal observation or light traps (where applicable).

7. Management measures

• Cultural: manual removal of caterpillars in small areas; destruction of spontaneous host plants; superficial tillage of the soil to expose pupae.
• Preventive: frequent monitoring in periods of greater risk; avoiding excessive vegetative vigour.
• Biological: promotion of natural enemies (parasitoids and predators).
• Integrated protection: judicious application of Bacillus thuringiensis in early stages; use of authorised insecticides only when necessary and in accordance with intervention thresholds.

Bibliographic references

• CABI – Invasive Species Compendium – Agrius convolvuli.
• EPPO Global Database – Agrius convolvuli.
• Alford, D. V. (2007). Pest and Disease Management Handbook. Blackwell Publishing.
• Carter, D. J. (1984). Pest Lepidoptera of Europe. Dr W. Junk Publishers.
• Robinson, G. S. et al. (2010). Hostplants of the moths of the world. Natural History Museum.