Assessing Taphrorychus bicolor (Coleoptera: Curculionidae) as a forest pest in central Europe: ecology, monitoring, and management strategies

Taphrorychus bicolor (Coleoptera: Curculionidae, Scolytinae) is emerging as a potential threat to European beech (Fagus sylvatica L.) in Central Europe, particularly under recurrent drought and a warming climate. We review its ecology, damage symptoms, monitoring methods, and management strategies, integrating published research with recent observations from Slovakia. Regarded as a secondary pest of dead or dying wood, T. bicolor has also been observed infesting living beech trees, producing characteristic lesions that degrade timber quality and may accelerate tree decline. These injuries marked by sap exudation, blister-like bark, and black fluid-filled lesions occur more frequently in drought-stressed stands, especially along forest edges and south-facing slopes. Monitoring trials demonstrated that pheromone-baited traps and felled beech trap trees effectively attract large numbers of beetles, although outbreak thresholds for this species are not yet defined. We recommend preventive management through timely removal and treatment of logging residues and weakened trees to reduce breeding sites. Biological control options, including the predator Nemozoma elongatum and entomopathogenic fungi such as Beauveria bassiana, show promise but require further study. A critical knowledge gap remains regarding the role of secondary infections in lesion development following beetle infestation. Whether T. bicolor represents a persistent threat or a transient response to climatic stress remains unclear, but proactive monitoring and management are essential to mitigate its impact on beech forests. This review provides an updated basis for forest managers, researchers, and policymakers confronting the challenges posed by T. bicolor.