Study of Walnut brown rot caused by Botryosphaeria dothidea in the Guizhou Province of China

Abstract

Walnut (Juglans regia L.), known as the “longevity fruit” in the nut world, is one of the most famous dried fruits with excellent economic value and health care effects. Between July and September 2021, exocarps of green walnut fruits were affected by the brown rot disease in the Shiqian, Sinan, Dejiang, and Hezhang counties of the Guizhou Province, causing severe economic losses. Morphological, pathogenicity tests and molecular biological techniques confirmed that the pathogen isolated from walnut fruit was Botryosphaeria dothidea. To the best of our knowledge, this is the first report of B. dothidea causing brown rot in walnuts in China. The findings from this study will provide a basis for subsequent research to develop preventative measures for rot caused by this fungus in walnuts.