Silky leaf weevil

The Silky leaf weevil (Polydrusus sericeus) is a beetle species belonging to the Curculionidae family within the order Coleoptera. It is a well-known pest in horticultural systems, easily recognized by its characteristic metallic green or bronze-colored scales that give the insect a distinct silky appearance.

This pest affects a wide range of host plants, predominantly focusing on fruit trees and woody shrubs. Common hosts include pome fruits like apple and pear, stone fruits such as cherry and plum, as well as various forest trees including hazel and birch. The diversity of host plants allows the population to thrive even in diversified agricultural landscapes.

The life cycle of the Silky leaf weevil involves a soil-dwelling larval stage and an active adult stage. The larvae develop in the ground, feeding primarily on the fine root systems of their host plants. As they mature, they pupate in the soil, and adults emerge in the spring, coinciding with the swelling of buds, providing them with an immediate food source.

The damage caused by adults is primarily defoliation. They chew irregular notches along the leaf margins, which, in severe cases, can lead to the near-total consumption of leaf blades. This activity weakens the tree, reduces photosynthetic efficiency, and can stunt growth, especially in young saplings. Larval root feeding, while less visible, can also contribute to nutrient deficiency and reduced plant vigor.

Management of Polydrusus sericeus requires an integrated approach to pest management. Effective strategies include:

• Cultivation of soil around the base of trees to disturb larvae and pupae.
• Use of sticky traps or physical barriers on trunks to prevent adults from climbing.
• Strategic application of targeted insecticides during peak emergence if population levels exceed threshold limits.
• Maintaining general orchard hygiene by removing overgrown vegetation that provides additional shelter.