Apple Leaf Miner

Leucoptera malifoliella

1. Identification

• Common name: Pear leaf blister moth
• Scientific name: Leucoptera malifoliella O. G. Costa
• Synonym: Leucoptera scitella Zeller
• Order: Lepidoptera
• Family: Lyonetiidae

2. Pest description

• Adults: Small moths of about 6–8 mm wingspan; forewings white with silvery spots and darkened margins; hindwings narrow and fringed
• Larvae: Yellowish-white body, very small; they live inside the leaves, forming characteristic mines
• Pupae: Develop inside the mine, usually protected by a silky cocoon
• Eggs: Laid singly on the leaf surface, usually on the upper side

3. Main hosts

• Apple tree
• Pear trees and other rosaceous plants may occasionally be affected

4. Symptoms and damage

• Serpentine mines that develop into irregular and translucent spots on the leaves
• Drying and necrosis of the mined areas
• Premature leaf drop in intense attacks
• Reduction of the photosynthetic capacity and vigour of the tree
• In severe infestations, decrease in production and greater susceptibility to other pests and diseases

5. Biological cycle

• Two to four annual generations, depending on climatic conditions
• Eggs laid in spring; larvae quickly penetrate the leaf to begin the mine
• Larval development with several instars within the same mine
• Pupation inside the mine or occasionally on the leaf surface
• Adults emerge throughout spring and summer, with flight peaks varying according to the region

6. Monitoring

• Direct observation of recent and active mines on the leaves
• Counting of mined leaves on representative shoots
• Pheromone traps for detection and tracking of adult flights
• Assessment of the intensity of defoliation and the evolution of mines throughout the season

7. Management measures

• Cultural: removal and destruction of heavily attacked leaves, collection of fallen leaves in autumn and maintenance of balanced orchards to reduce pest pressure.
• Biological: use of authorised bioinsecticides with action on young larvae and promotion of natural enemies that attack eggs and larvae.
• Integrated protection: regular monitoring, intervention only when attack levels justify it and application of measures that reduce the survival of larvae within the mines.

Bibliographic references

• EPPO Global Database – Leucoptera malifoliella
• CABI Invasive Species Compendium – Leucoptera malifoliella
• Blommers, L. H. M. (1994). Integrated pest management in European apple orchards
• Alford, D. V. (2007). Pest and Disease Management Handbook. Blackwell Publishing
• Dickler, E. (1976). Biology and control of Leucoptera scitella in apple orchards