Identification, Biological Characteristics and Screening of Control Agents of Ardisia crenata Sims Root Rot from China

Zhien Xiao¹Tiantian Guo¹Yuxin Liu¹Yue Yuan¹Shaotian Zhang¹Lu Liu²Shiying He¹Yanling Long¹Fuqiang Yin^1*Ming Liu^1*

• ¹Chongqing Three Gorges University, Wanzhou, Chongqing Municipality, China
• ²Chongqing Three Gorges Vocational College, College of Agriculture and Forestry Science and Technology, Chongqing, China, Wanzhou, China

Ardisia crenata Sims is included in the Chinese Pharmacopoeia and is a valuable traditional medicinal plant. A. crenata Sims root rot was first detected in 2023 in Kaizhou District, Chongqing City, China. This study was undertaken to elucidate the causal pathogen of A. crenata Sims root rot, the biological characteristics of the pathogen, and to screen effective pesticides for its management. A pathogenic fungus was isolated and purified from typical lesions on A. crenata Sims, and it was identified by using morphological and multi-gene combined analysis. The biological characteristics of the pathogen were investigated using the cross-inoculation method and spore counting technique, while the sensitivity of the pathogen to 6 chemical pesticides and 6 biological pesticides was evaluated using the growth rate method. The combination of morphology and polygenic association identified the pathogenic fungus as Fusarium cugenangense a member of the F. oxysporum species complex. This is the first report of F. cugenangense causing root rot disease in A. crenata Sims. Among 6 tested chemical pesticides, 500 g/L Fluazinam suspension concentrate (SC) showed the best inhibitory effect, with an half maximal effective concentration (EC50) value of 0.129 μg/mL. Among 6 tested biological pesticides, 3% Zhongshengmycin soluble liquid (SL) showed the best inhibitory effect, with an EC50 value of 14.474 μg/mL. The conclusion is expected to lay a scientific basis for diagnosis and control of A. crenata Sims root rot caused by F. cugenangense.