Colletotrichum gloeosporioides s. str., the causal agent of a leaf spot disease of Schefflera arboricola in Iran

Schefflera arboricola is a flowering plant in the family Araliaceae; its common name is dwarf umbrella tree. It is an evergreen shrub and a popular ornamental plant, commonly grown as an indoor plant. During a sampling in 2015, a new leaf spot symptoms was observed on S. arboricola plants in several greenhouses in the Hamadan province, Iran. Most of the plants were severely damaged by this disease. The presumed causal agent was isolated from symptomatic leaves. Based on morphological and cultural characteristics, the fungus was identified as a Colletotrichum species, probably belonging to the C. gloeosporioides species complex. By means of molecular data (TUB2 GAPDH) the fungus was revealed to be C. gloeosporioidessensu stricto. Pathogenicity tests showed that the fungus is the causal agent of leaf spot on S. arboricola shrubs. To our knowledge, this is the first report of C. gloeosporioides sensu stricto on S. arboricola in Iran.