First Report of Zedoary Leaf Blight Caused by Neopestalotiopsis Asiatica on Curcuma Phaeocaulis in Guangxi, China

Abstract

Zedoary (Curcuma phaeocaulis Valeton), a traditional Chinese medicine, is renowned for its therapeutic properties. However, in 2017, a leaf blight disease caused by a novel pathogen, Neopestalotiopsis asiatica, was discovered, severely impacting its yield and quality. The pathogen was identified through morphological characterization and sequence analysis of rDNA ITS, TEF, and TUB regions, isolated using single-conidial isolation, and confirmed with Koch's postulates. The pathogen's optimal growth temperature was found to be 25°C, with a lethal temperature of 55°C for 10 minutes. Biolog phenotypic analysis revealed the pathogen's utilization rates of carbon, nitrogen, phosphorus, and sulfur sources, with only 2'-deoxyadenosine among 94 biosynthetic pathway substances promoting its growth. Additionally, certain ion concentrations affected pathogen growth, with higher concentrations hindering it. Twelve fungicides were tested, and the 96% prochloraz-manganese chloride complex significantly inhibited both mycelial growth and spore germination. This study represents the first identification of the zedoary leaf blight pathogen in Guangxi, China, and suggests effective fungicides for disease control.

Keywords: Curcuma phaeocaulis Valeton, Zedoary leaf blight, Neopestalotiopsis asiatica, Management