Pathogenicity and fungicide sensitivity of Phytophthora parvispora, a new pathogen causing gummosis and root rot disease on citrus trees

• Published in: Microbial pathogenesis 2023-02, Vol.175, p.105986-105986, Article 105986
• Main Authors: Van Tran, Quang, Ha, Cuong Viet, Vvedensky, Valentin Valentinovich, Linh Le, Thi Thuy, Han, Viet-Cuong
• Format: Article
• Language: English
• Subjects: Brown fruit rot; Citrus; Cytochrome oxidase subunit I; Fungicides, Industrial - pharmacology; Oomycetes; Oomycides; Phytophthora - genetics; Phytophthora cinnamomi; Trees; Virulence
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2023.105986

In 2021, pomelo (Citrus grandi) trees grown in Tuyen Quang and Phu Tho in northern Vietnam suffered from leaf yellowing, gummosis on stems, brown rot on fruit, and black rot on roots. Based on morphological and sequence analysis of the ITS and cox1 gene regions, the pathogen causing gummosis and root rot of citrus trees was identified as Phytophthora parvispora. Pathogenicity assays using mycelial plugs and zoospore suspension showed that P. parvispora induces disease symptoms on both the upper and lower parts of various citrus trees, including pomelo, orange (C. sinensis), and lime (C. aurantiifolia). This is the first report of P. parvispora as the causative agent of gummosis and root rot on various citrus trees in South-East Asia as well as in Vietnam. Further, P. parvispora was sensitive to all tested fungicides, including mancozeb, chlorothalonil, fosetyl aluminium, potassium phosphonate, and dimethomorph. These findings will have important implications for the effective management of gummosis and root rot disease of citrus trees. •First report of Phytophthora parvispora causing gummosis and root rot of citrus trees.•P. parvispora inducing disease symptoms on different parts of different citrus trees.•P. parvispora showing varying degrees of susceptibility to oomycota fungicides.