New Zealand leafroller

The Planotortrix excessana, commonly referred to as the New Zealand leafroller, is a moth species belonging to the family Tortricidae. It is a notorious agricultural pest, particularly known for its ability to infest a diverse range of botanical hosts and cause significant damage to commercial fruit production.

This species is highly polyphagous, meaning it feeds on a wide variety of plants. Common host crops include pomaceous fruits such as apples and pears, stone fruits, citrus, and grapevines. In addition, it often colonizes nursery stock and various ornamental plants, making it a persistent challenge for both commercial growers and landscape managers.

The life cycle follows a complete metamorphosis consisting of egg, larval, pupal, and adult stages. Females lay eggs in clusters on leaves. Upon hatching, the larvae immediately seek shelter by webbing leaves together. They spend their larval development inside these protective structures, feeding on leaf tissue and occasionally tunneling into developing fruits.

The damage caused by the New Zealand leafroller is multifaceted. By feeding on leaves, the larvae reduce the photosynthetic capacity of the plant. However, the primary economic damage occurs when larvae feed on the surface of the fruit, causing scarring and deformities that disqualify the produce from export or premium domestic markets.

Successful management of this pest requires a multifaceted Integrated Pest Management (IPM) approach. Key strategies involve:

• Monitoring adult populations using pheromone-baited traps.
• Implementing biological controls, such as the application of entomopathogenic bacteria.
• Targeted insecticide applications during peak larval activity periods.
• Cultural practices like pruning canopy growth to improve chemical coverage and reduce nesting sites.