Aphid A. scariolae

Acyrthosiphon scariolae

1. Identification

• Common name: Lettuce aphid (frequent designation in technical literature).
• Scientific name: Acyrthosiphon scariolae Koch
• Order: Hemiptera
• Family: Aphididae

2. Pest description

• Apterous adults: Elongated body, light green to yellowish-green; long cylindrical siphunculi; well-developed cauda.
• Alate adults: Darkened head and thorax; transparent wings; yellowish-green body.
• Nymphs: Similar to apterous adults, but smaller and lighter.

3. Main hosts

• Species of the genus Lactuca (lettuce).
• Also recorded on Cichorium spp. and other wild Asteraceae.

4. Symptoms and damage

• Curling and deformation of young leaves.
• Reduction of vigour and growth delay.
• Excretion of honeydew, favouring the development of sooty mould.
• Potential to act as a vector of phytopathogenic viruses associated with horticultural crops.

5. Biological cycle

• Species predominantly anholocyclic in temperate climate regions, reproducing by parthenogenesis during much of the year.
• Rapid development, with multiple annual generations.
• Populations increase mainly in mild climate conditions and absence of natural predators.

6. Monitoring

• Direct observation of the lower side of young leaves.
• Assessment of the presence of colonies and honeydew.
• Counting of individuals per plant to support decision-making in integrated protection.

7. Management measures

• Cultural: Removal of infested plants; control of spontaneous host plants; appropriate management of planting density.
• Biological: Conservation of beneficials such as Coccinellidae, Syrphidae and Aphidiinae.
• Integrated protection: Intervention only when population levels justify it; preference for selective products compatible with beneficials.

Bibliographic references

• Blackman, R. L., & Eastop, V. F. (2000). Aphids on the World’s Crops: An Identification and Information Guide. Wiley.
• Blackman, R. L., & Eastop, V. F. (2006). Aphids on the World’s Herbaceous Plants and Shrubs. Wiley.
• van Emden, H. F., & Harrington, R. (2017). Aphids as Crop Pests (2nd ed.). CABI.
• Dixon, A. F. G. (1998). Aphid Ecology: An Optimization Approach. Chapman & Hall.