Apple leaf midge

Dasineura mali

1. Identification

• Common name: Apple leaf-curling midge
• Scientific name: Dasineura mali Kieffer
• Order: Diptera
• Family: Cecidomyiidae

2. Pest description

• Very small adults (about 2 mm), similar to small gnats.
• Fragile body, transparent wings and long legs.
• Yellowish-orange larvae, apodous, develop inside the leaves.
• They induce the characteristic curling of young leaves.
• Pupation in the soil, in surface chambers.

3. Main hosts

• Apple tree (main host).
• It may occasionally affect other species of Malus.
• More frequent in young and vigorous orchards.

4. Symptoms and damage

• Curling of young leaves, forming small pouches.
• Presence of larvae inside the deformed leaves.
• Reduction of the photosynthetic area.
• Delayed growth of the shoots.
• In severe attacks, reduction of vigour and yield.

5. Biological cycle

• Several generations per year, depending on temperature.
• Adults emerge in spring and lay eggs on young leaves.
• Larvae develop inside the leaves over 1–2 weeks.
• Pupation in the soil, where they remain until the next emergence.
• Cycle favoured by tender shoots and humid conditions.

6. Monitoring

• Observation of curled young leaves.
• Opening of affected leaves for detection of larvae.
• Regular monitoring during vegetative growth.
• Recording of favourable conditions (vigorous shoots and high humidity).
• Assessment of attack intensity to determine the need for intervention.

7. Management measures

• Cultural: removal and destruction of attacked leaves, improvement of air circulation, management of plant vigour and reduction of excessively tender shoots.
• Biological: conservation of natural parasitoids and use of entomopathogens in the soil when authorised.
• Integrated protection: continuous monitoring, interventions targeted only when necessary and integration of cultural practices to reduce oviposition and larval development sites.

Bibliographic references

• EPPO Global Database – Dasineura mali.
• CABI Invasive Species Compendium – D. mali.
• Cross, J. V. et al. (1999). Pests of pome fruit in temperate regions.
• Blommers, L. H. M. et al. (2003). Biology and control of gall midges in apple orchards.