Gray-banded leafroller

The Gray-banded leafroller (Argyrotaenia mariana) is a moth belonging to the order Lepidoptera and the family Tortricidae. It is a well-documented pest of economic significance, primarily known for causing damage to various deciduous trees, with a strong preference for commercial fruit orchards.

The pest primarily infests pome fruits and stone fruits, including apple, pear, cherry, and plum trees. While it focuses on fruit-bearing trees, it can also survive on a variety of wild host plants found in the proximity of orchards, which often serves as a reservoir for re-infestation during the growing season.

The life cycle typically consists of two generations per year. The insect overwinters in the larval stage, hiding within cocoons attached to bark crevices or leaf litter. As spring temperatures rise, the larvae emerge to feed on developing buds and foliage. The subsequent generations involve egg-laying on leaves, followed by larval development that damages both vegetative and reproductive parts.

Damage is characterized by larvae folding and tying leaves together with silk, creating a protective enclosure. However, the most severe economic damage occurs when the larvae feed on the fruit. They create shallow, irregular scars on the surface of apples and pears, which significantly reduces the quality and marketability of the crop, and provides entry points for secondary pathogens.

• Deployment of pheromone traps to monitor adult flight activity.
• Sanitation practices, including the removal of infested fruits and leaf litter.
• Encouragement of natural predators and parasitoids such as wasps.
• Application of selective insecticides targeting the larval stage.
• Regular orchard scouting to determine the timing of interventions.

Management strategies focus on integrated pest management (IPM) to maintain populations below economic thresholds. Monitoring flight patterns with pheromone traps is essential to optimize the timing of insecticide applications. By targeting the early larval stages before they form protective leaf rolls, growers can achieve significant control while minimizing the impact on non-target organisms.