Pear blight beetle

The pear blight beetle (Monarthrum mali) is a wood-boring insect belonging to the family Curculionidae, subfamily Scolytinae. It is a type of ambrosia beetle that is recognized for its ability to excavate tunnels deep into the heartwood of deciduous trees, posing a significant risk to tree health in orchards and forest environments.

This pest affects a wide range of host plants, predominantly apple, pear, plum, and various species of oak, maple, and beech. The beetle is particularly attracted to stressed trees, such as those suffering from drought, mechanical injuries, or root diseases, which have compromised physiological defense systems.

The biology of Monarthrum mali is distinct due to its symbiotic relationship with ambrosia fungi. Adult beetles bore into the xylem, introducing fungal spores into their galleries. The larvae do not feed on wood directly but consume the fungus, which thrives on the walls of the tunnels created by the parents.

Damage caused by the beetle manifests as small, circular entry holes in the bark, often accompanied by frass. The internal tunneling disrupts the tree's vascular system, leading to wilting, branch dieback, and in severe cases, the death of the entire tree. The presence of the beetle often indicates that the tree is already under significant stress.

• Implement strict sanitation practices by removing and destroying infested wood.
• Avoid leaving logging residues near orchard sites to prevent beetle population buildup.
• Ensure optimal irrigation and fertilization to keep trees vigorous and resistant.
• Utilize pheromone monitoring to detect early activity of the pests.
• Apply systemic or contact insecticides during the flight period as a last resort in high-risk zones.