First Report of Poinsettia Mosaic Virus and Poinsettia Latent Virus in Crown of Thorns in Florida

Crown of Thorns ( Euphorbia milii) is a hardy perennial with spiny stems that produce numerous flowers enclosed within bracts of various colors. In February 2024, virus-like symptoms were observed on several Crown of Thorns plants in commercial nurseries and residential plantings in southeast Florida. Symptoms varied across plants and included flecking, mottling, ringspots, irregular leaf margins, and flower break. Reverse transcription polymerase chain reaction (RT-PCR) confirmed that five plants were infected with Euphorbia ringspot virus (EuRSV; Potyvirus euphorbiae) and five individual plants were infected with Poinsettia mosaic virus (PnMV; Poinsettia mosaic virus). Next generation sequencing was used to characterize and confirm the complete genome of PnMV, and additional analyses revealed three plants were coinfected with Poinsettia latent virus (PnLV; Polemovirus PNLV). To the best of our knowledge, this is the first report of PnMV and PnLV in Crown of Thorns in Florida.