Occurrence of Neofusicoccum parvum Associated With Dieback of Ailanthus altissima in Italy

The invasive deciduous tree Ailanthus altissima, native to China, has rapidly spread worldwide and is now considered one of the most ecologically disruptive species. During a survey carried out in 2024 in Rome province, trees exhibiting severe dieback symptoms were documented, including canopy decline, internal wood discoloration and necrotic lesions on both the outer and inner bark. Morphological and molecular analyses identified Neofusicoccum parvum as the causal agent, and pathogenicity tests confirmed its role in disease development. Given the invasiveness of A. altissima and the high pathogenic potential of N. parvum, their interaction could provide new chances for natural constraint to its spread. This study represents the first report of N. parvum infecting A. altissima in Italy, emphasising its significance for ecosystem dynamics and invasive species containment.