Symptoms of TRV infection include yellow ring spotting and concentric line patterns. Symptoms either persist, vary seasonally, or disappear soon after infection depending on the host species and virus strain. TRV has a host range of over 350 plant species and is transmitted by soil-inhabiting nematodes of the genus Trichodorus, mechanically (on infected tools), grafting, and seed. It is not spread by plant to plant contact. Important crop hosts include potato, spinach, beet, beans and pepper. Important ornamental hosts include Narcissus, Gladiolus, Calendula, Tulipa, Petunia X hybrida and vinca. TRV is increasing in vegetatively propagated perennials and has been reported on Dicentra, Heuchera and Hyacinthus.