Leaf-eating weevil

Systematic position: The leaf-eating weevil (Phyllobius arborator) is a member of the order Coleoptera and the family Curculionidae. It is characterized by its short rostrum and is frequently encountered in forest ecosystems, orchards, and parks across Europe.

Host plants: This pest has a wide host range, primarily attacking various deciduous trees and shrubs. Common hosts include alder, birch, willow, and hazel. Furthermore, it causes significant economic damage to fruit-bearing trees, particularly apples, pears, and cherries, which are highly susceptible to leaf damage in the spring.

Biology and life cycle: The beetle undergoes complete metamorphosis. It typically overwinters in the soil as a larva, where it feeds on the roots of various plants. In the spring, the larvae pupate in the soil, and the adults emerge to feed on foliage. The peak activity of the adult beetles occurs during late spring, followed by mating and egg-laying in the soil near the host plants.

Nature of damage and harmfulness: Adults cause damage by chewing irregular notches along the margins of the leaves. In cases of severe infestations, they can lead to extensive defoliation, which severely stresses the trees and reduces their photosynthetic capacity. Larvae damage the roots, which can be particularly detrimental to young nursery trees and saplings, potentially stunting their growth.

Control measures: Managing Phyllobius arborator requires a multi-faceted approach:

• Application of contact or systemic insecticides during the peak emergence of adults.
• Soil cultivation around the base of trees to disturb or kill overwintering larvae.
• Maintaining a healthy ecosystem to encourage natural predators like birds and predatory beetles.
• Installation of sticky barriers or traps to monitor and limit the movement of the beetles.