Update on cucurbit yellow vine disease caused by Serratia ureilytica
Cucurbit yellow vine disease (CYVD - formerly EPPO Alert List; EPPO RS 1999/134) was considered to be caused by the Gram-negative bacterium Serratia marcescens (Enterobacteriaceae). However, Mphande et al. (2025) recently showed that CYVD is caused by Serratia ureilytica, and that this species belongs to the S. marcescens complex. CYVD was observed for the first time in the USA in 1988 in Oklahoma and Texas (EPPO RS 1999/134). It has expanded its distribution and currently has a wide distribution in the USA, East of the Rocky Mountains. CYVD has been reported on watermelon (Citrullus lanatus), melon (Cucumis melo), courgette and pumpkin (Cucurbita pepo), and giant pumpkin (Cucurbita maxima). Affected plants show leaf yellowing, stem elongation, phloem discoloration, stunting, vine decline and collapse. Disease incidence can reach up to 100%. The squash bug Anasa tristis (Heteroptera: Coreidae), which feeds on cucurbits, was previously known to vector the bacterium. Mphande et al. (2025) demonstrated experimentally that two beetles could also act as vectors: the spotted cucumber beetle (Diabrotica undecimpunctata howardi, EPPO A1 List) and the striped cucumber beetle (Acalymma vittatum) (both Coleoptera: Chrysomelidae). Both species have sometimes been observed in CYVD-infested fields in the absence of A. tristis.
Limited data is available on S. ureilytica. It was described from water in West Bengal (India) in 2005. Like S. marcescens (EPPO RS 2026/102), it has been reported from the environment and described as a human and animal pathogen. It was not possible to fully document its distribution.
It is worth noting that, to date, CYVD has not been reported outside of the USA. The bacterium causing a leaf chlorosis and necrosis disease on squash (Cucurbita pepo var. styriaca) in Iran (Sedighian et al., 2018) was not closely-related to strains from cucurbits causing CYVD, but to strains of S. marcescens isolated from bell pepper (Capsicum annuum) and maize (Zea mays).
Information on Serratia ureilytica has been added to EPPO Global Database: https://gd.eppo.int/taxon/SERRUR
Sources
Bhadra B, Roy P, Chakraborty R (2005) Serratia ureilytica sp. nov., a novel urea-utilizing species. International Journal of Systematic and Evolutionary Microbiology 55, 2155-2158.
JKI (2019) Express PRA for Serratia marcescens. Julius Kühn-Institute, Germany. Available at https://pra.eppo.int/pra/0e916861-b044-44c5-83b2-269a406f4b45
Mphande K, LaSarre B, Paulsen AA, Hartung R, Badilla-Arias S, Gleason ML, Beattie GA (2025) Bacteria that cause cucurbit yellow vine disease fall within the Serratia ureilytica species of the S. marcescens complex and can be vectored by cucumber beetles. Phytopathology 115(6), 606-617.
Rodriguez-Herrera KD, Pethybridge SJ, Reiners S, Nault B, Swingle B, Smart CD (2026) Cucurbit Yellow Vine Disease. A new bacterial disease of cucurbits in N.Y. caused by Serratia ureilytica. Cornell Vegetables. https://www.vegetables.cornell.edu/pest-management/disease-factsheets/cucurbit-yellow-vine-disease/
Sedighian, N., Taghavi, S.M., Osdaghi, E, Shams-Bakhsh M (2018) Serratia marcescens associated with squash leaf chlorosis and necrotic spots in Iran. Journal of Plant Pathology 100, 85–89.
Wong-Villareal A, Ruiz-Sánchez E, Cua-Basulto M, Espinosa-Zaragoza S, González-Sánchez AA, Ramos-Carbajal E, Góngora-Gamboa C, Garruña-Hernández R, Romero-Tirado R, Moreno-Basurto G, Pinson-Rincón EP (2025) Acaricidal activity of biosurfactants produced by Serratia ureilytica on Tetranychus urticae and their compatibility with the predatory mite Amblyseius swirskii. Microbiology Research 16(7),150.