Pine weevil

The pine weevil (lat. Magdalis duplicata) is a wood-boring beetle belonging to the family Curculionidae and the order Coleoptera. This insect is primarily recognized as a secondary pest that targets coniferous forests, specifically focusing on weakened or stressed pine trees within its geographic range.

This species primarily damages pine trees (Pinus spp.) and occasionally spruce. It is particularly attracted to trees stressed by drought, wildfire, or poor site conditions. While often considered a secondary pest, under favorable conditions, it can reach high population densities and become a primary threat to young plantations.

The life cycle is typically univoltine, meaning one generation per year. Adults emerge in late spring to feed on the bark of young twigs. Females then lay eggs in the bark of trunks or branches. Larvae hatch and create complex tunnels in the cambium and phloem layers, effectively girdling the vascular tissues of the tree.

The damage caused by Magdalis duplicata includes branch dieback, crown yellowing, and general thinning of the tree canopy. In severe cases, the larval galleries can cause the death of the tree limb or the entire host tree, facilitating secondary infestations by more aggressive pathogens and wood-boring insects.

Management strategies for this pest revolve around silvicultural practices to maintain forest vigor. These include:

• Prompt removal and disposal of infested trees during the dormant season.
• Sanitation cutting to reduce the overall population of the beetle.
• Enhancing forest biodiversity to support natural predators of the weevil.
• Monitoring flight periods in high-value nurseries to apply targeted chemical controls.