Large aspen tortrix

Choristoneura spp.

1. Identification

• Common name: Large poplar tortrix
• Scientific name: Choristoneura spp.
• Order: Lepidoptera
• Family: Tortricidae

2. Pest description

• Greenish-brown caterpillars, very mobile, which roll leaves with silken threads.
• Adults with brown forewings showing variable patterns and pale hindwings.
• They attack young leaves, shoots and, occasionally, inflorescences.
• Species typical of broadleaf trees, with periodic outbreaks that can cause significant defoliation.

3. Main hosts

• Aspen.
• Poplar.
• Willow.
• Birch.
• Other broadleaf trees of riparian and forest areas.

4. Symptoms and damage

• Leaves rolled and bound together by silken threads.
• Holes and consumption of the leaf blade.
• Partial or severe defoliation in intense attacks.
• Reduction in vigor and annual growth.
• Greater susceptibility to other pests and diseases in weakened trees.

5. Biological cycle

• One generation per year in most regions.
• Eggs laid in batches on leaves in summer.
• Caterpillars overwinter in shelters in the bark or in the leaf litter.
• They resume activity in spring, feeding on young leaves.
• Pupation inside rolled leaves.
• Adults emerge in early summer.

6. Monitoring

• Observation of rolled leaves and presence of caterpillars.
• Checking for damage to shoots and young leaves.
• Monitoring with pheromone traps (when available for the local species).
• Assessment of defoliation intensity throughout the spring.

7. Management measures

• Cultural: removal of attacked leaves and branches, destruction of crop residues and improvement of tree vitality.
• Biological: use of Bacillus thuringiensis on young caterpillars and conservation of natural enemies.
• Integrated protection: regular monitoring, interventions only when justified and judicious application of authorized insecticides.

Bibliographic references

• EPPO Global Database – Choristoneura spp..
• CABI Invasive Species Compendium – Choristoneura spp..
• Nealis, V. G. (2016). Ecology of Choristoneura species in forest ecosystems. Forest Ecology and Management.
• Ives, W. G. H. (1981). Population dynamics of Choristoneura spp. in deciduous forests. Canadian Entomologist.
• Alford, D. (2007). Pest management in forest and shade trees.