Plum curculio

The plum curculio (Coccotorus scutellaris) is a significant pest belonging to the Curculionidae family of the order Coleoptera. It is widely recognized by horticulturists and agronomists as a destructive insect that targets various stone fruit crops, posing a constant challenge to commercial orchard productivity in North America and beyond.

This beetle species primarily affects stone fruits, with a strong preference for plums, peaches, cherries, and apricots. Its ability to infest developing fruit makes it a primary economic threat, as the larvae feed internally on the fruit, causing extensive damage and often leading to total crop loss if left uncontrolled.

The biological cycle involves adult beetles overwintering in protected areas such as bark crevices or leaf litter. As spring temperatures rise, the adults emerge and begin feeding on buds and blossoms. Following mating, females lay eggs inside the fruit. The development from larva to adult is closely synchronized with the growth stages of the host fruit.

The damage caused by Coccotorus is characterized by crescent-shaped oviposition scars on the surface of the fruit. Inside, the larvae bore through the flesh to the pit, consuming the seed kernel. This feeding process results in premature fruit drop, secondary fungal infections, and severe deformation of the harvestable crop.

Integrated Pest Management (IPM) is essential for effective control. Growers should focus on:

• Rigorous sanitation by collecting and disposing of all dropped fruit daily.
• Applying insecticide sprays precisely at the petal-fall stage to target adult activity.
• Maintaining orchard hygiene, including the removal of debris near tree bases to limit overwintering sites for the adult beetles.