Dormouse injuries predispose beech to infection by Neonectria ditissima.

After awaking from winter hibernation, the Edible dormouse begins to feed by stripping the bark and the outer part of the xylem from the branches of both broadleaves and conifers. Natural or artificial wounds are essential for the penetration and colonisation of the tissues by the fungal pathogen Neonectria ditissima. This pathogen creates open cankers on beech branches and other broadleaves, which are frequently later infected by wood-decaying fungi. Because of the high frequencies of both dormouse injuries and branch cankers in a large monospecific beech forest in northern Italy, field and laboratory investigations were conducted to verify whether rodent-inflicted injuries on beech were a preferred infection point for the pathogen. These studies also examined the susceptibility to infection of the dormouse-inflicted wounds over time, and the relationships between dormouse damage, Neonectria infection, and wood decay. The results showed a significant direct correlation between the percentage of infections and their proximity to the wounds, indicating that the parasite localises to sites where there are receptive dormouse injuries. In addition, the susceptibility of the wound was found to diminish with increasing age, disappearing in 120-150 days. The association between dormouse injuries, Neonectria cankers and wood decay was also found to cause approximately half of the frequent beech branch breakages during intense weather events.