New information of Ceratobasidium sp. associated with vascular streak dieback of woody ornamentals in the USA
Further research has been carried out on vascular streak dieback (VSD) of woody ornamentals (EPPO Alert List) in the USA (EPPO RS 2024/110). Reliable detection tests have now been developed (PCR and qPCR). Phylogenetic studies showed that the sequences of the VSD agent and Ceratobasidium theobromae are closely related but it is now considered that the VSD agent may represent a separate, previously unrecognized species (named ‘Ceratobasidium sp. D.P. Rogers’ in the literature and abbreviated as Csp). Koch’s postulates have not been completed because of the fastidious nature of Csp. However a metagenomic study by Belay et al. (2026) concludes that Csp is the only causative agent of VSD on ornamentals in the USA.
Liyanapathiranage et al. (2025) noted that VSD has been recently recorded for the first time in several US states: Alabama, Maryland, Oregon, Missouri, Pennsylvania, South Carolina. In Virginia, it was recorded mainly in nurseries (58% of the 91 nurseries tested), but also in 8 landscape sites (3 municipal parks, 3 city streets, 1 residence, and 1 forest restoration site).
Since the first reports of VSD (RS 2024/110), the host range of the pathogen has increased from 25 to 46 host genera, including two coniferous hosts. Liyanapathiranage et al. (2025) and Bily et al. (2026) report the following new host plants: Abelia x grandiflora, Aesculus sylvatica, Albizia julibrissin, Betula nigra, Carpinus betulus, Carpinus caroliniana, Carya glabra, Celtis occidentalis, Cephalanthus occidentalis, Chionanthus retusus, Cladrastis kentukea, Cotinus coggygria, Ginkgo biloba, Heptacodium miconioides, Hydrangea arborescens, Ilex glabra, Juniperus chinensis, Lagerstroemia indica, Liquidambar styraciflua, Magnolia ashei, Magnolia grandiflora, Magnolia virginiana, Osmanthus heterophyllus, Osmanthus x fortunei, Oxydendrum arboreum, Platanus x hispanica, Prunus americana,, Prunus persica, Prunus x yedoensis, Quercus alba, Q. rubra, Q. shumardii, Rhododendron hybrids, Salix japonica, Sassafras albidum, Spiraea japonica, Styrax japonicus, Taxodium distichum, Tilia americana, Ulmus parviflora, Viburnum macrocephalum, and V. opulus.
The economic impact of VSD in the USA was investigated by Liyanage et al. (2025) based on a survey conducted in 2023 in seven US states. On average, growers reported around $375,000 worth of losses attributed to VSD in ∼25% of container plants.
Sources
Belay KH, Abdelrazek S, Kaur S, Mazloom R, Bily D, Gyatso T, Avin FA, Bonkowski J, Liyanapathiranage P, Rodriguez Salamanca L, Heath LS (2026) Genomic insights into Ceratobasidium sp. associated with vascular streak dieback of woody ornamentals in the United States using a metagenomic sequencing approach. Microbiology Spectrum e02523-25. https://doi.org/10.1128/spectrum.02523-25
Bily D, Gyatso T, Avin FA, Bonkowski J, Liyanapathiranage P, Rodriguez Salamanca L, Vinatzer B, Baysal-Gurel F (2026) A Ceratobasidium sp. D.P. Rogers associated with vascular streak dieback of woody ornamental plants in Virginia, U.S.A. Plant Disease (early view) https://doi.org/10.1094/PDIS-02-25-0375-RE
Liyanage KH, Liyanapathiranage P, Baysal-Gurel F (2025) Investigating the economic impact of emerging vascular streak dieback threat to redbuds in the us nursery industry. HortScience 60(7), 1244-1250. DOI: 10.21273/HORTSCI18589-25
Liyanapathiranage P, Avin FA, Bonkowski J, Beckerman JL, Munster M, Hadziabdic D, Trigiano RN, Baysal-Gurel F (2025) Vascular streak dieback: A novel threat to redbud and other woody ornamental production in the United States. Plant Disease 109(5), 953-970