Developmental Biology and Seasonal Damage of the Grape Borer Xylotrechus pyrrhoderus in Grapevines.

Xylotrechus pyrrhoderus Bates (Coleoptera: Cerambycidae) is a major viticultural pest whose larval feeding damages grapevine canes and reduces yields, yet its internal development and damage progression are poorly understood. Using field surveys combined with micro-computed tomography (micro-CT) and in situ X-ray microscopy, we non-destructively tracked both tissue damage and life-cycle dynamics within canes. Damage intensity increased from December to May, with affected canes showing reduced porosity compared to healthy ones. Continuous imaging revealed a distinct prepupal stage and extended adult residence in pupal chambers before emergence. Morphometric analysis showed that adult size is constrained by pupal chamber dimensions, indicating adaptive adjustment to limited intra-cane space. These findings demonstrate the value of advanced imaging tools for clarifying the biology of X. pyrrhoderus and support the development of targeted management strategies for this and related agricultural pests.