First report of Fusarium crown and root rot on Torreya grandis caused by Fusarium oxysporum species complex in China.

Abstract

In 2009, sporadic occurrence of crown rot disease was recorded in Shaoxing City (Zhejiang, China), which produces 80% yields of T. grandis in China. In 2014, approximately 37% of orchards and 4.5% of trees were affected in Shaoxing. Symptoms were crown rot characterized by light-brown discoloration of the cambium, with brownish black necrotic areas which appeared on the roots and often advanced to the collar on most plants. Diseased trees showed reduced vigour and chlorosis on the foliage and eventually died. Based on morphology, development of macroconidia and microconida, molecular data (rDNA internal transcribed spacers and translation elongation factor 1-alpha gene) and pathogenicity tests, a fungus belonging to the F. oxysporum species complex was identified. This is thought to be the first report of T. grandis crown and root rot caused by fungus belonging to the F. oxysporum species complex worldwide.