Brown ring formation and streak mottle, two distinct syndromes in lilies associated with complex infections of lily symptomless virus and tulip breaking virus

Abstract

Brown ring formation in bulbs of lilies, particularly of Mid-century hybrids, is described as a newly recognized disease. Symptoms of streak mottle in cultivars of Lilium speciosum Thunb., not associated with abnormalities of bulbs, are briefly described with reference to the literature. Sometimes the two syndromes occur in the same crop such as in the Mid-century hybrid 'Enchantment', showing brown ring formation in bulbs and an indistinct mottling in field plants. Severe leaf mottling appears in Midcentury hybrids and L. speciosum when plants are forced under glass. In both diseases tulip breaking virus (TBV) was always found to occur in complex with lily symptomless virus (LSV), which was consistently detected in apparently healthy plants of the Mid-century hybrid 'Enchantment' and in several L. speciosum cultivars. The part of TBV involved in the complex diseases described has been demonstrated by serological, electron-microscopical, and inoculation studies with lilies and tulips. LSV was sap-transmitted from lily to tulip but it could not be detected in several randomly taken samples of a dozen field-grown tulip cultivars. Suppression of TBV in plants of 'Enchantment', grown from bulbs with brown ring formation under field conditions, is discussed. TBV was serologically and electron-microscopically detectable only in plants grown under glass. A similar phenomenon was observed in L. speciosum cultivars under both conditions. © 1973 Koninklijke Nederlandse Planteziektenkundige Vereniging.