Evaluation and control of Epicoccum nigrum causing stem blight in raspberry in China

Raspberry is highly valued by consumers owing to its palatability and medicinal applications. However, from June to August 2023, a severe outbreak of raspberry stem blight (RSB) in Harbin, China, significantly impacted raspberry yield and quality. In this study, the causal agent of RSB was identified as Epicoccum nigrum . To the best of our knowledge, this is the first report of E. nigrum causing RSB in China. Pathogenicity assays revealed moderate virulence of the isolated strains. Additionally, E. nigrum was found to infect elderberry, chicken twig, honey suckle, mountain thorn, yellow thorn rose, rose, maack spindle-tree, and mountain celery, but not hawthorn. The E. nigrum isolate exhibited high sensitivity to prochloraz (EC ₅₀  ≤ 0.50 μg·ml ⁻¹ ), with 81.1% efficacy observed at 0.00045 g·ml ⁻¹ . These findings suggest that integrated strategies, such as crop rotation between host and non-host plants combined with the application of chemical fungicides, could effectively control RSB. This study provides a critical foundation for the prevention and management of RSB in China.