Acta Agriculturae Zhejiangensis ›› 2026, Vol. 38 ›› Issue (4): 696-706.DOI: 10.3969/j.issn.1004-1524.20250254

• Plant Protection • Previous Articles     Next Articles

Isolation, identification, and control of the pathogen causing leaf spot disease on Hydrangea macrophylla Bo Dalan

ZHANG Yu1(), CHEN Jingjing1, WEN Lianhao1, YANG Zhenyi2, YANG Cenghua2, TONG Yi2, WANG Chao1,*()   

  1. 1 Southwest Research Center for Landscape Architecture Engineering, State Forestry and Grassland Administration, Yunnan Province Engineering Research Center for Functional Flower Resources and Industrialization, Key Laboratory of Forest Disaster Warning and Control in Universities of Yunnan Province, Yunnan Province South and Southeast Asia Joint R&D Center of Economic Forest Full Industry Chain,Southwest Forestry University, Kunming 650224, China
    2 Kunming Yang Yueji Horticulture Co., Ltd., Kunming 652501, China
  • Received:2025-04-02 Online:2026-04-25 Published:2026-05-08
  • Contact: WANG Chao

Abstract:

To identify the pathogen causing leaf spot disease on Hydrangea macrophylla Bo Dalan and investigate its biological characteristics and effective control agents, thereby providing a theoretical basis for the scientific management of this disease, this study isolated the pathogen from diseased samples collected at the Nanguo Shanhua Hydrangea Germplasm Resource Base in Yuxi City, Yunnan Province, using the tissue isolation method. The pathogenicity was verified according to Koch’s postulates. The pathogen was identified based on morphological observations and multi-gene sequence (ITS, LSU, TUB) analysis. The effects of different culture media, carbon sources, nitrogen sources, temperature, light conditions, and pH value on the mycelial growth of the pathogen were studied using the mycelial growth rate method. Additionally, nine commonly used fungicides were selected to determine their in vitro toxicity against the pathogen. The results showed that the primary pathogen isolated from the infected leaves was Epicoccum sorghinum. The biological characteristics tests indicated that the optimal conditions for mycelial growth were PDA medium with maltose as the carbon source and peptone and beef extract as nitrogen sources, at a temperature of 25 ℃, pH value 7.0, and under continuous light. The in vitro toxicity tests revealed that 10% difenoconazole water dispersible granules (WG) had the best inhibitory effect, with an EC50 value of 1.252 2 mg·L-1. In conclusion, the pathogen causing leaf spot disease on H. macrophylla Bo Dalan was E. sorghinum, and 10% difenoconazole WG exhibited a strong inhibitory effect against this pathogen, making it a potential candidate for field control.

Key words: Hydrangea Bo Dalan, leaf spot disease, pathogen, Epicoccum sorghinum, biological characteristic, 10% difenoconazole water dispersible granules (WG)

CLC Number: