Green leafroller

Taxonomic status: The green leafroller (Planotortrix octo) belongs to the order Lepidoptera and the family Tortricidae. It is a significant agricultural pest, particularly in New Zealand, recognized for its ability to cause severe economic losses in various orchard environments due to its highly adaptable nature.

Host range: This moth is a polyphagous pest, meaning it feeds on a wide variety of plant species. The primary crops affected include pipfruit such as apples and pears, stone fruit like peaches and nectarines, and commercially significant crops like kiwifruit. Its ability to infest diverse plant species makes it a persistent challenge for orchard management.

Biology and life cycle: The life cycle of Planotortrix octo consists of egg, larval, pupal, and adult stages. Depending on environmental conditions, the pest can complete several generations per year. Overwintering occurs primarily in the larval stage, protected within silk shelters created on twigs, bark crevices, or remaining dry leaves, allowing them to emerge rapidly when favorable conditions return.

Damage and economic impact: Larvae are the primary cause of damage. Young larvae graze on leaf surfaces, creating small holes, while older larvae bind leaves together with silk webbing and feed extensively. When feeding on fruit, the larvae create deep entry holes that lead to physiological decay and direct loss of marketable produce, which can be devastating for export-oriented agriculture.

Management strategies: Effective control requires an Integrated Pest Management (IPM) approach.

• Deployment of pheromone traps to monitor adult moth populations.
• Targeted insecticide applications timed specifically to the larval emergence period.
• Utilization of biological control agents, including parasitic wasps and predatory bugs.
• Implementation of orchard hygiene practices to remove potential overwintering sites.