Serpentine leafminer

Liriomyza huidobrensis

1. Identification

• Common name: Pea leafminer
• Scientific name: Liriomyza huidobrensis Blanchard
• Order: Diptera
• Family: Agromyzidae

2. Pest description

• Adults: small flies of 1.7–2.3 mm; dark body with yellow patterns; transparent wings; females with a robust ovipositor for leaf perforation.
• Larvae: legless, pale yellow to cream in colour; develop inside the leaves, producing long, winding serpentine mines.
• Pupae: generally in the soil, but may occur on the leaf surface; brown colouration.
• Eggs: deposited individually in the leaf tissue, leaving small visible perforations.

3. Main hosts

• Vegetables: potato, bean, pea, lettuce, onion, tomato, pepper, cucumber.
• Ornamentals: chrysanthemum, gerbera, gypsophila.
• Other cultivated and spontaneous dicotyledons may serve as reservoirs.

4. Symptoms and damage

• Long, narrow serpentine mines, often very winding.
• Pinpoint perforations caused by the females during oviposition and feeding.
• Necrosis of the mined areas and partial drying of the leaf.
• Significant reduction in photosynthetic capacity.
• In severe attacks, intense defoliation and loss of vigour.
• Decreased production and greater susceptibility to secondary infections.

5. Biological cycle

• Rapid cycle, which can be completed in 2–3 weeks under favourable conditions.
• Larvae develop through 3 instars inside the mine.
• Pupation mainly in the soil.
• Adults emerge throughout the year in greenhouses; outdoors, peaks in spring and summer.
• High fecundity and several generations per year.
• Highly invasive species, with great dispersal capacity.

6. Monitoring

• Direct observation of recent serpentine mines.
• Counting of mined leaves on representative plants.
• Yellow chromotropic traps for adult detection.
• Frequent monitoring in greenhouses, where the pest develops more rapidly.
• Assessment of the evolution of the mines and the intensity of defoliation.

7. Management measures

• Cultural: removal of heavily attacked leaves, elimination of spontaneous host plants, improvement of greenhouse ventilation.
• Biological: conservation of natural parasitoids (e.g.: Diglyphus isaea, Dacnusa sibirica) and use of authorised bioinsecticides on young larvae.
• Integrated protection: continuous monitoring, intervention only when necessary, rotation of modes of action and practices that reduce larval and pupal survival.

Bibliographic references

• EPPO Global Database – Liriomyza huidobrensis.
• CABI Invasive Species Compendium – Liriomyza huidobrensis.
• Parrella, M. P. (1987). Biology of Liriomyza species. Annual Review of Entomology, 32, 201–224.
• Weintraub, P. G., & Horowitz, A. R. (1998). The newest leafminer pest in Israel: Liriomyza huidobrensis. Phytoparasitica, 26, 1–6.
• Spencer, K. A. (1973). Agromyzidae (Diptera) of Economic Importance. Dr. W. Junk Publishers.