Acta Agriculturae Zhejiangensis ›› 2026, Vol. 38 ›› Issue (2): 301-309.DOI: 10.3969/j.issn.1004-1524.20240999

• Plant Protection • Previous Articles     Next Articles

Identification of the pathogen causing mulberry snags rotten leaves disease and resistance of 47 mulberry varieties

CHEN Quan1,2(), LI Hui1,2, YANG Jing1,2, XU Songlin1,2, ZHANG Shukang1,2, LIU Zhongxian2,3,*(), HE Jinhui3,*()   

  1. 1. Chongqing Three Gorges Academy of Agricultural Sciences, Chongqing 404155, China
    2. College of Biology and Food Engineering, Chongqing Three Gorges University, Chongqing 404100, China
    3. Economic Crop Development Center in Wanzhou District of Chongqing City, Chongqing 404401, China
  • Received:2024-11-21 Online:2026-02-25 Published:2026-03-24

Abstract:

To identify the pathogen responsible for the prevalent leaf diseases in the mulberry production area of Qianjiang, Chongqing, and to evaluate the resistance levels of different mulberry varieties for establishing precise and efficient control methods to reduce mulberry leaf loss, this study was conducted. Through field sampling, indoor isolation and cultivation, PCR amplification of ITS, ACT, TUB, and TEF gene fragments, and construction of a phylogenetic tree, the pathogen was identified. The resistance of 47 mulberry varieties was evaluated by in vitro leaf inoculation and assessment of disease incidence and average diameter of disease spots after 6 days. The strain HBB1, isolated from mulberry leaves in Qianjiang District, Chongqing, was identified as a new variant of the mulberry snags rotten leaves disease (Boeremia exigua), named Boeremia exigua var. mori. After inoculation with HBB1, the incidence rate reached 100% for 21 varieties including Chuansang 7657, Husang 32, and Nongsang 14, while Chuansang 90-4 showed the lowest incidence rate (53.84%). Regarding disease spot diameter, 6 varieties including Chuan Sang 33, Chuan Sang 39, and Chuan Sang 7657 exhibited disease spot diameters greater than 12 mm, and were classified as highly susceptible varieties. In contrast, Fushe 1 showed a disease spot diameter of 2.09 mm, identifying it as a highly resistant variety. Additionally, 32 varieties demonstrated resistance or moderate resistance. In conclusion, this study is the first to confirm that the pathogen causing mulberry snags rotten leaves disease in Qianjiang, Chongqing, is the new variety Boeremia exigua var. mori. It systematically reveals the differences in resistance among mulberry varieties to this pathogen, providing a scientific basis for breeding resistant varieties and implementing precise disease control.

Key words: mulberry, snags rotten leaves disease, Boeremia exigua var. mori, pathogen identification, resistance evaluation

CLC Number: