Molecular Identification of Fusarium Species Associated with Foliar Diseases of Durian ( Durio zibethinus ) in Hainan, China

Durian (Durio zibethinus) is an economically important tropical fruit endemic to Southeast Asia. Hainan is a new region for durian cultivation. Foliar diseases of durian were common at all durian orchards during field surveys carried out from October 2023 to October 2024 in Hainan, China. In this study, Fusarium species associated with durian foliar disease in Hainan (China) were studied based on multilocus phylogenetic analyses using translation elongation factor 1-α (tef1), partial RNA polymerase second largest subunit (RPB2), and calmodulin (CaM). Six Fusarium species, F. pernambucanum, F. sulawesiense, F. hainanense, F. irregulare, F. mangiferae, and F. concentricum, were identified. Pathogenicity tests showed that all six species were pathogenic to detached wounded and unwounded durian leaves except F. irregulare, which only induced visible symptoms on wounded durian leaves. The findings from this study expand the pathogenic fungal species on durian as this is the first report of these Fusarium spp. causing durian leaf disease worldwide.