Boxelder maple (Acer negundo L.) is widely grown as amental trees in China.In 2017 in Pizhou,Jiangsu Province,China,the boxelder maple trees suffered from a disease which caused wilting and yellowing leaves,rotted roots,and discolored xylem.The disease broke out from July to August.Seven fungal isolates were obtained from symptomatic tissue and tested for pathogenicity.Isolate An7 was isolated at high frequency from the discolored vascular tissues,which caused the wilt disease on healthy 2-year-old seedlings after inoculation and eventually killed all the seedlings.We conducted molecular analysis for An7,including the partial sequences of the rDNA intal transcribed spacer,calmodulin,RNA polymerase Ⅱ second largest subunit and the translation elongation factor 1-α and evaluation of the variously sized conidia,chlamydospores and conidiophores and cultural traits.The pathogen was identified as Fusarium nirenbergiae,a member of the Fusarium oxysporum species complex.To our knowledge,this is the first report of F.nirenbergiae causing wilt on A.negundo in China.