Identification and fungicide sensitivity of Alternaria tenuissima causing leaf spot of Tetrapanax papyrifer newly reported in China

Abstract

Tetrapanax papyrifer, the rice‐paper plant, is an evergreen shrub and is traditionally used as a herbal medicine in China. In October 2021, a serious leaf spot disease was extensively observed on T. papyrifer in Guizhou, China. Given the limited information available about the aetiology of this disease, isolations were performed, the morphological characteristics and multi‐locus phylogenetic analysis of the fungus associated with the disease were described, and the pathogenicity tests and Koch's postulates were completed. To our knowledge, this is the first report of leaf spot on T. papyrifer caused by Alternaria tenuissima in China. Among 11 fungicides tested, 10% difenoconazole WDG had the best inhibition effect in vitro with EC50 values at 0.1 μg mL−1. This study provides new information for the identification and chemical control of Alternaria leaf spot of T. papyrifer.